Commit Graph

2586 Commits

Author SHA1 Message Date
Linus Torvalds
4c797b11a8 vfs-6.13.file
-----BEGIN PGP SIGNATURE-----
 
 iHUEABYKAB0WIQRAhzRXHqcMeLMyaSiRxhvAZXjcogUCZzcW4gAKCRCRxhvAZXjc
 okF+AP9xTMb2SlnRPBOBd9yFcmVXmQi86TSCUPAEVb+wIldGYwD/RIOdvXYJlp9v
 RgJkU1DC3ddkXtONNDY6gFaP+siIWA0=
 =gMc7
 -----END PGP SIGNATURE-----

Merge tag 'vfs-6.13.file' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull vfs file updates from Christian Brauner:
 "This contains changes the changes for files for this cycle:

   - Introduce a new reference counting mechanism for files.

     As atomic_inc_not_zero() is implemented with a try_cmpxchg() loop
     it has O(N^2) behaviour under contention with N concurrent
     operations and it is in a hot path in __fget_files_rcu().

     The rcuref infrastructures remedies this problem by using an
     unconditional increment relying on safe- and dead zones to make
     this work and requiring rcu protection for the data structure in
     question. This not just scales better it also introduces overflow
     protection.

     However, in contrast to generic rcuref, files require a memory
     barrier and thus cannot rely on *_relaxed() atomic operations and
     also require to be built on atomic_long_t as having massive amounts
     of reference isn't unheard of even if it is just an attack.

     This adds a file specific variant instead of making this a generic
     library.

     This has been tested by various people and it gives consistent
     improvement up to 3-5% on workloads with loads of threads.

   - Add a fastpath for find_next_zero_bit(). Skip 2-levels searching
     via find_next_zero_bit() when there is a free slot in the word that
     contains the next fd. This improves pts/blogbench-1.1.0 read by 8%
     and write by 4% on Intel ICX 160.

   - Conditionally clear full_fds_bits since it's very likely that a bit
     in full_fds_bits has been cleared during __clear_open_fds(). This
     improves pts/blogbench-1.1.0 read up to 13%, and write up to 5% on
     Intel ICX 160.

   - Get rid of all lookup_*_fdget_rcu() variants. They were used to
     lookup files without taking a reference count. That became invalid
     once files were switched to SLAB_TYPESAFE_BY_RCU and now we're
     always taking a reference count. Switch to an already existing
     helper and remove the legacy variants.

   - Remove pointless includes of <linux/fdtable.h>.

   - Avoid cmpxchg() in close_files() as nobody else has a reference to
     the files_struct at that point.

   - Move close_range() into fs/file.c and fold __close_range() into it.

   - Cleanup calling conventions of alloc_fdtable() and expand_files().

   - Merge __{set,clear}_close_on_exec() into one.

   - Make __set_open_fd() set cloexec as well instead of doing it in two
     separate steps"

* tag 'vfs-6.13.file' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
  selftests: add file SLAB_TYPESAFE_BY_RCU recycling stressor
  fs: port files to file_ref
  fs: add file_ref
  expand_files(): simplify calling conventions
  make __set_open_fd() set cloexec state as well
  fs: protect backing files with rcu
  file.c: merge __{set,clear}_close_on_exec()
  alloc_fdtable(): change calling conventions.
  fs/file.c: add fast path in find_next_fd()
  fs/file.c: conditionally clear full_fds
  fs/file.c: remove sanity_check and add likely/unlikely in alloc_fd()
  move close_range(2) into fs/file.c, fold __close_range() into it
  close_files(): don't bother with xchg()
  remove pointless includes of <linux/fdtable.h>
  get rid of ...lookup...fdget_rcu() family
2024-11-18 10:30:29 -08:00
Linus Torvalds
4a5df37964 10 hotfixes, 7 of which are cc:stable. All singletons, please see the
changelogs for details.
 -----BEGIN PGP SIGNATURE-----
 
 iHUEABYIAB0WIQTTMBEPP41GrTpTJgfdBJ7gKXxAjgUCZzkr6AAKCRDdBJ7gKXxA
 jsb2AP9HCOI4w9rQTmBdnaefXytS7fiiPq+LVNpjJ0NGXX2FSgD/e1NM0wi8KevQ
 npcvlqTcXtRSJvYNF904aTNyDn+Kuw0=
 =KFGY
 -----END PGP SIGNATURE-----

Merge tag 'mm-hotfixes-stable-2024-11-16-15-33' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull hotfixes from Andrew Morton:
 "10 hotfixes, 7 of which are cc:stable. All singletons, please see the
  changelogs for details"

* tag 'mm-hotfixes-stable-2024-11-16-15-33' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
  mm: revert "mm: shmem: fix data-race in shmem_getattr()"
  ocfs2: uncache inode which has failed entering the group
  mm: fix NULL pointer dereference in alloc_pages_bulk_noprof
  mm, doc: update read_ahead_kb for MADV_HUGEPAGE
  fs/proc/task_mmu: prevent integer overflow in pagemap_scan_get_args()
  sched/task_stack: fix object_is_on_stack() for KASAN tagged pointers
  crash, powerpc: default to CRASH_DUMP=n on PPC_BOOK3S_32
  mm/mremap: fix address wraparound in move_page_tables()
  tools/mm: fix compile error
  mm, swap: fix allocation and scanning race with swapoff
2024-11-16 16:00:38 -08:00
Dan Carpenter
669b0cb81e fs/proc/task_mmu: prevent integer overflow in pagemap_scan_get_args()
The "arg->vec_len" variable is a u64 that comes from the user at the start
of the function.  The "arg->vec_len * sizeof(struct page_region))"
multiplication can lead to integer wrapping.  Use size_mul() to avoid
that.

Also the size_add/mul() functions work on unsigned long so for 32bit
systems we need to ensure that "arg->vec_len" fits in an unsigned long.

Link: https://lkml.kernel.org/r/39d41335-dd4d-48ed-8a7f-402c57d8ea84@stanley.mountain
Fixes: 52526ca7fd ("fs/proc/task_mmu: implement IOCTL to get and optionally clear info about PTEs")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Cc: Andrei Vagin <avagin@google.com>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: David Hildenbrand <david@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Cc: Muhammad Usama Anjum <usama.anjum@collabora.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-11-14 22:43:48 -08:00
Linus Torvalds
28e43197c4 20 hotfixes, 14 of which are cc:stable.
Three affect DAMON.  Lorenzo's five-patch series to address the
 mmap_region error handling is here also.
 
 Apart from that, various singletons.
 -----BEGIN PGP SIGNATURE-----
 
 iHUEABYKAB0WIQTTMBEPP41GrTpTJgfdBJ7gKXxAjgUCZzBVmAAKCRDdBJ7gKXxA
 ju42AQD0EEnzW+zFyI+E7x5FwCmLL6ofmzM8Sw9YrKjaeShdZgEAhcyS2Rc/AaJq
 Uty2ZvVMDF2a9p9gqHfKKARBXEbN2w0=
 =n+lO
 -----END PGP SIGNATURE-----

Merge tag 'mm-hotfixes-stable-2024-11-09-22-40' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull misc fixes from Andrew Morton:
 "20 hotfixes, 14 of which are cc:stable.

  Three affect DAMON. Lorenzo's five-patch series to address the
  mmap_region error handling is here also.

  Apart from that, various singletons"

* tag 'mm-hotfixes-stable-2024-11-09-22-40' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
  mailmap: add entry for Thorsten Blum
  ocfs2: remove entry once instead of null-ptr-dereference in ocfs2_xa_remove()
  signal: restore the override_rlimit logic
  fs/proc: fix compile warning about variable 'vmcore_mmap_ops'
  ucounts: fix counter leak in inc_rlimit_get_ucounts()
  selftests: hugetlb_dio: check for initial conditions to skip in the start
  mm: fix docs for the kernel parameter ``thp_anon=``
  mm/damon/core: avoid overflow in damon_feed_loop_next_input()
  mm/damon/core: handle zero schemes apply interval
  mm/damon/core: handle zero {aggregation,ops_update} intervals
  mm/mlock: set the correct prev on failure
  objpool: fix to make percpu slot allocation more robust
  mm/page_alloc: keep track of free highatomic
  mm: resolve faulty mmap_region() error path behaviour
  mm: refactor arch_calc_vm_flag_bits() and arm64 MTE handling
  mm: refactor map_deny_write_exec()
  mm: unconditionally close VMAs on error
  mm: avoid unsafe VMA hook invocation when error arises on mmap hook
  mm/thp: fix deferred split unqueue naming and locking
  mm/thp: fix deferred split queue not partially_mapped
2024-11-10 09:04:27 -08:00
Qi Xi
b8ee299855 fs/proc: fix compile warning about variable 'vmcore_mmap_ops'
When build with !CONFIG_MMU, the variable 'vmcore_mmap_ops'
is defined but not used:

>> fs/proc/vmcore.c:458:42: warning: unused variable 'vmcore_mmap_ops'
     458 | static const struct vm_operations_struct vmcore_mmap_ops = {

Fix this by only defining it when CONFIG_MMU is enabled.

Link: https://lkml.kernel.org/r/20241101034803.9298-1-xiqi2@huawei.com
Fixes: 9cb218131d ("vmcore: introduce remap_oldmem_pfn_range()")
Signed-off-by: Qi Xi <xiqi2@huawei.com>
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/lkml/202410301936.GcE8yUos-lkp@intel.com/
Cc: Baoquan He <bhe@redhat.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Wang ShaoBo <bobo.shaobowang@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-11-07 14:14:59 -08:00
David Wang
84b9749a3a proc/softirqs: replace seq_printf with seq_put_decimal_ull_width
seq_printf is costy, on a system with n CPUs, reading /proc/softirqs
would yield 10*n decimal values, and the extra cost parsing format string
grows linearly with number of cpus. Replace seq_printf with
seq_put_decimal_ull_width have significant performance improvement.
On an 8CPUs system, reading /proc/softirqs show ~40% performance
gain with this patch.

Signed-off-by: David Wang <00107082@163.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2024-11-07 07:40:14 -10:00
Linus Torvalds
7166c32651 vfs-6.12-rc5.fixes
-----BEGIN PGP SIGNATURE-----
 
 iHUEABYKAB0WIQRAhzRXHqcMeLMyaSiRxhvAZXjcogUCZxY6XAAKCRCRxhvAZXjc
 opmUAQCu4KhzBBdZmFw3AfZFNJvYb1onT4FiU0pnyGgfvzEdEwD6AlnlgQ7DL3ZN
 WBqBzUl+DpGYJfzhkqoEGH89Fagx7QM=
 =mm68
 -----END PGP SIGNATURE-----

Merge tag 'vfs-6.12-rc5.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull vfs fixes from Christian Brauner:
 "afs:
   - Fix a lock recursion in afs_wake_up_async_call() on ->notify_lock

 netfs:
   - Drop the references to a folio immediately after the folio has been
     extracted to prevent races with future I/O collection

   - Fix a documenation build error

   - Downgrade the i_rwsem for buffered writes to fix a cifs reported
     performance regression when switching to netfslib

  vfs:
   - Explicitly return -E2BIG from openat2() if the specified size is
     unexpectedly large. This aligns openat2() with other extensible
     struct based system calls

   - When copying a mount namespace ensure that we only try to remove
     the new copy from the mount namespace rbtree if it has already been
     added to it

  nilfs:
   - Clear the buffer delay flag when clearing the buffer state clags
     when a buffer head is discarded to prevent a kernel OOPs

  ocfs2:
   - Fix an unitialized value warning in ocfs2_setattr()

  proc:
   - Fix a kernel doc warning"

* tag 'vfs-6.12-rc5.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
  proc: Fix W=1 build kernel-doc warning
  afs: Fix lock recursion
  fs: Fix uninitialized value issue in from_kuid and from_kgid
  fs: don't try and remove empty rbtree node
  netfs: Downgrade i_rwsem for a buffered write
  nilfs2: fix kernel bug due to missing clearing of buffer delay flag
  openat2: explicitly return -E2BIG for (usize > PAGE_SIZE)
  netfs: fix documentation build error
  netfs: In readahead, put the folio refs as soon extracted
2024-10-21 10:48:24 -07:00
Thorsten Blum
197231da7f
proc: Fix W=1 build kernel-doc warning
Building the kernel with W=1 generates the following warning:

  fs/proc/fd.c:81: warning: This comment starts with '/**',
                   but isn't a kernel-doc comment.

Use a normal comment for the helper function proc_fdinfo_permission().

Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
Link: https://lore.kernel.org/r/20241018102705.92237-2-thorsten.blum@linux.dev
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-10-18 13:02:47 +02:00
Brahmajit Das
5778ace04e fs/proc: fix build with GCC 15 due to -Werror=unterminated-string-initialization
show show_smap_vma_flags() has been a using misspelled initializer in
mnemonics[] - it needed to initialize 2 element array of char and it used
NUL-padded 2 character string literals (i.e.  3-element initializer).

This has been spotted by gcc-15[*]; prior to that gcc quietly dropped the
3rd eleemnt of initializers.  To fix this we are increasing the size of
mnemonics[] (from mnemonics[BITS_PER_LONG][2] to
mnemonics[BITS_PER_LONG][3]) to accomodate the NUL-padded string literals.

This also helps us in simplyfying the logic for printing of the flags as
instead of printing each character from the mnemonics[], we can just print
the mnemonics[] using seq_printf.

[*]: fs/proc/task_mmu.c:917:49: error: initializer-string for array of `char' is too long [-Werror=unterminate d-string-initialization]
  917 |                 [0 ... (BITS_PER_LONG-1)] = "??",
      |                                                 ^~~~
fs/proc/task_mmu.c:917:49: error: initializer-string for array of `char' is too long [-Werror=unterminate d-string-initialization]
fs/proc/task_mmu.c:917:49: error: initializer-string for array of `char' is too long [-Werror=unterminate d-string-initialization]
fs/proc/task_mmu.c:917:49: error: initializer-string for array of `char' is too long [-Werror=unterminate d-string-initialization]
fs/proc/task_mmu.c:917:49: error: initializer-string for array of `char' is too long [-Werror=unterminate d-string-initialization]
fs/proc/task_mmu.c:917:49: error: initializer-string for array of `char' is too long [-Werror=unterminate d-string-initialization]
...


Stephen pointed out:

: The C standard explicitly allows for a string initializer to be too long
: due to the NUL byte at the end ...  so this warning may be overzealous.

but let's make the warning go away anwyay.

Link: https://lkml.kernel.org/r/20241005063700.2241027-1-brahmajit.xyz@gmail.com
Link: https://lkml.kernel.org/r/20241003093040.47c08382@canb.auug.org.au
Signed-off-by: Brahmajit Das <brahmajit.xyz@gmail.com>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-10-17 00:28:07 -07:00
Alexander Gordeev
3d5854d75e fs/proc/kcore.c: allow translation of physical memory addresses
When /proc/kcore is read an attempt to read the first two pages results in
HW-specific page swap on s390 and another (so called prefix) pages are
accessed instead.  That leads to a wrong read.

Allow architecture-specific translation of memory addresses using
kc_xlate_dev_mem_ptr() and kc_unxlate_dev_mem_ptr() callbacks similarily
to /dev/mem xlate_dev_mem_ptr() and unxlate_dev_mem_ptr() callbacks.  That
way an architecture can deal with specific physical memory ranges.

Re-use the existing /dev/mem callback implementation on s390, which
handles the described prefix pages swapping correctly.

For other architectures the default callback is basically NOP.  It is
expected the condition (vaddr == __va(__pa(vaddr))) always holds true for
KCORE_RAM memory type.

Link: https://lkml.kernel.org/r/20240930122119.1651546-1-agordeev@linux.ibm.com
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Suggested-by: Heiko Carstens <hca@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-10-09 12:47:19 -07:00
Al Viro
be5498cac2 remove pointless includes of <linux/fdtable.h>
some of those used to be needed, some had been cargo-culted for
no reason...

Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2024-10-07 13:34:41 -04:00
Al Viro
8fd3395ec9 get rid of ...lookup...fdget_rcu() family
Once upon a time, predecessors of those used to do file lookup
without bumping a refcount, provided that caller held rcu_read_lock()
across the lookup and whatever it wanted to read from the struct
file found.  When struct file allocation switched to SLAB_TYPESAFE_BY_RCU,
that stopped being feasible and these primitives started to bump the
file refcount for lookup result, requiring the caller to call fput()
afterwards.

But that turned them pointless - e.g.
	rcu_read_lock();
	file = lookup_fdget_rcu(fd);
	rcu_read_unlock();
is equivalent to
	file = fget_raw(fd);
and all callers of lookup_fdget_rcu() are of that form.  Similarly,
task_lookup_fdget_rcu() calls can be replaced with calling fget_task().
task_lookup_next_fdget_rcu() doesn't have direct counterparts, but
its callers would be happier if we replaced it with an analogue that
deals with RCU internally.

Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2024-10-07 13:34:41 -04:00
Linus Torvalds
172d513936 Summary
* Bug fix: Avoid evaluating non-mount ctl_tables as a sysctl_mount_point by
   removing the unlikely (but possible) chance that the permanently empty
   ctl_table array shares its address with another ctl_table.
 * Update Joel Granados' contact info in MAINTAINERS.
 
 Testing
 
 * Bug fix merged to linux-next after 6.11-rc5
 -----BEGIN PGP SIGNATURE-----
 
 iQGzBAABCgAdFiEErkcJVyXmMSXOyyeQupfNUreWQU8FAmbtUfsACgkQupfNUreW
 QU+ptAv+JEbJR+VMLDZk3xAm1iRvqyzpVank8pJGgdp3kSYPY1KdJqAHo+ZXAD1r
 jtJMwyI4ELIQ7NnLq50qUCPScdBpXpG73QVp8Foip43x0E/pOxiSiz5C0m4NbRsU
 cKQuiRauOpfqrNvh22TVB3jjpL4cZbRpyP1kpMgf8edn3YlhYhJ04oXjVUk+zMMA
 muUifAlUAUMhQiHOqLynA7ZObwlqY+QoiJF8v4IPAcynYk0ZKNBmqAAMdIoBF4c8
 rrgtIt/xlaJB6a1usS9B5xFbamrlaNPaiA3ul+lUeMLcArtoB5gwMTz+AGLu46aB
 +RCjhXmY3LBvMD16eyY9cge/3Qud2jyoyh0Qp9wHhgJwsaDWlG51qzi+PHr8ZtV5
 jdtk8QzHZs07JFsE2HabppCtrgNxnwPiwBS7xm45u/p8dZ7buCvtZm1MEjgHu9M/
 6iVSEs+/S3+AZMz+/K3WaqaP/kYhXklwT16xN7b1+oxLNFfJ2RLcx0Xc7yZpGwRM
 8YbaGnR2
 =85Xa
 -----END PGP SIGNATURE-----

Merge tag 'sysctl-6.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/sysctl/sysctl

Pull sysctl update from Joel Granados:

 - Avoid evaluating non-mount ctl_tables as a sysctl_mount_point by
   removing the unlikely (but possible) chance that the permanently
   empty ctl_table array shares its address with another ctl_table

 - Update Joel Granados' contact info in MAINTAINERS

* tag 'sysctl-6.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/sysctl/sysctl:
  MAINTAINERS: update email for Joel Granados
  sysctl: avoid spurious permanent empty tables
2024-09-24 11:08:40 -07:00
Linus Torvalds
7856a56541 Many singleton patches - please see the various changelogs for details.
Quite a lot of nilfs2 work this time around.
 
 Notable patch series in this pull request are:
 
 "mul_u64_u64_div_u64: new implementation" by Nicolas Pitre, with
 assistance from Uwe Kleine-König.  Reimplement mul_u64_u64_div_u64() to
 provide (much) more accurate results.  The current implementation was
 causing Uwe some issues in the PWM drivers.
 
 "xz: Updates to license, filters, and compression options" from Lasse
 Collin.  Miscellaneous maintenance and kinor feature work to the xz
 decompressor.
 
 "Fix some GDB command error and add some GDB commands" from Kuan-Ying Lee.
 Fixes and enhancements to the gdb scripts.
 
 "treewide: add missing MODULE_DESCRIPTION() macros" from Jeff Johnson.
 Adds lots of MODULE_DESCRIPTIONs, thus fixing lots of warnings about this.
 
 "nilfs2: add support for some common ioctls" from Ryusuke Konishi.  Adds
 various commonly-available ioctls to nilfs2.
 
 "This series fixes a number of formatting issues in kernel doc comments"
 from Ryusuke Konishi does that.
 
 "nilfs2: prevent unexpected ENOENT propagation" from Ryusuke Konishi.  Fix
 issues where -ENOENT was being unintentionally and inappropriately
 returned to userspace.
 
 "nilfs2: assorted cleanups" from Huang Xiaojia.
 
 "nilfs2: fix potential issues with empty b-tree nodes" from Ryusuke
 Konishi fixes some issues which can occur on corrupted nilfs2 filesystems.
 
 "scripts/decode_stacktrace.sh: improve error reporting and usability" from
 Luca Ceresoli does those things.
 -----BEGIN PGP SIGNATURE-----
 
 iHUEABYIAB0WIQTTMBEPP41GrTpTJgfdBJ7gKXxAjgUCZu7dpAAKCRDdBJ7gKXxA
 jsPqAPwMDEZyKlfSw7QioEHNHDkmkbP7VYCYR0CbUnppbztwpAD8D37aVbWQ+UzM
 3nnOq3W2Pc2o/20zqi8Upf1mnvUrygQ=
 =/NWE
 -----END PGP SIGNATURE-----

Merge tag 'mm-nonmm-stable-2024-09-21-07-52' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull non-MM updates from Andrew Morton:
 "Many singleton patches - please see the various changelogs for
  details.

  Quite a lot of nilfs2 work this time around.

  Notable patch series in this pull request are:

   - "mul_u64_u64_div_u64: new implementation" by Nicolas Pitre, with
     assistance from Uwe Kleine-König. Reimplement mul_u64_u64_div_u64()
     to provide (much) more accurate results. The current implementation
     was causing Uwe some issues in the PWM drivers.

   - "xz: Updates to license, filters, and compression options" from
     Lasse Collin. Miscellaneous maintenance and kinor feature work to
     the xz decompressor.

   - "Fix some GDB command error and add some GDB commands" from
     Kuan-Ying Lee. Fixes and enhancements to the gdb scripts.

   - "treewide: add missing MODULE_DESCRIPTION() macros" from Jeff
     Johnson. Adds lots of MODULE_DESCRIPTIONs, thus fixing lots of
     warnings about this.

   - "nilfs2: add support for some common ioctls" from Ryusuke Konishi.
     Adds various commonly-available ioctls to nilfs2.

   - "This series fixes a number of formatting issues in kernel doc
     comments" from Ryusuke Konishi does that.

   - "nilfs2: prevent unexpected ENOENT propagation" from Ryusuke
     Konishi. Fix issues where -ENOENT was being unintentionally and
     inappropriately returned to userspace.

   - "nilfs2: assorted cleanups" from Huang Xiaojia.

   - "nilfs2: fix potential issues with empty b-tree nodes" from Ryusuke
     Konishi fixes some issues which can occur on corrupted nilfs2
     filesystems.

   - "scripts/decode_stacktrace.sh: improve error reporting and
     usability" from Luca Ceresoli does those things"

* tag 'mm-nonmm-stable-2024-09-21-07-52' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (103 commits)
  list: test: increase coverage of list_test_list_replace*()
  list: test: fix tests for list_cut_position()
  proc: use __auto_type more
  treewide: correct the typo 'retun'
  ocfs2: cleanup return value and mlog in ocfs2_global_read_info()
  nilfs2: remove duplicate 'unlikely()' usage
  nilfs2: fix potential oob read in nilfs_btree_check_delete()
  nilfs2: determine empty node blocks as corrupted
  nilfs2: fix potential null-ptr-deref in nilfs_btree_insert()
  user_namespace: use kmemdup_array() instead of kmemdup() for multiple allocation
  tools/mm: rm thp_swap_allocator_test when make clean
  squashfs: fix percpu address space issues in decompressor_multi_percpu.c
  lib: glob.c: added null check for character class
  nilfs2: refactor nilfs_segctor_thread()
  nilfs2: use kthread_create and kthread_stop for the log writer thread
  nilfs2: remove sc_timer_task
  nilfs2: do not repair reserved inode bitmap in nilfs_new_inode()
  nilfs2: eliminate the shared counter and spinlock for i_generation
  nilfs2: separate inode type information from i_state field
  nilfs2: use the BITS_PER_LONG macro
  ...
2024-09-21 08:20:50 -07:00
Linus Torvalds
617a814f14 ALong with the usual shower of singleton patches, notable patch series in
this pull request are:
 
 "Align kvrealloc() with krealloc()" from Danilo Krummrich.  Adds
 consistency to the APIs and behaviour of these two core allocation
 functions.  This also simplifies/enables Rustification.
 
 "Some cleanups for shmem" from Baolin Wang.  No functional changes - mode
 code reuse, better function naming, logic simplifications.
 
 "mm: some small page fault cleanups" from Josef Bacik.  No functional
 changes - code cleanups only.
 
 "Various memory tiering fixes" from Zi Yan.  A small fix and a little
 cleanup.
 
 "mm/swap: remove boilerplate" from Yu Zhao.  Code cleanups and
 simplifications and .text shrinkage.
 
 "Kernel stack usage histogram" from Pasha Tatashin and Shakeel Butt.  This
 is a feature, it adds new feilds to /proc/vmstat such as
 
     $ grep kstack /proc/vmstat
     kstack_1k 3
     kstack_2k 188
     kstack_4k 11391
     kstack_8k 243
     kstack_16k 0
 
 which tells us that 11391 processes used 4k of stack while none at all
 used 16k.  Useful for some system tuning things, but partivularly useful
 for "the dynamic kernel stack project".
 
 "kmemleak: support for percpu memory leak detect" from Pavel Tikhomirov.
 Teaches kmemleak to detect leaksage of percpu memory.
 
 "mm: memcg: page counters optimizations" from Roman Gushchin.  "3
 independent small optimizations of page counters".
 
 "mm: split PTE/PMD PT table Kconfig cleanups+clarifications" from David
 Hildenbrand.  Improves PTE/PMD splitlock detection, makes powerpc/8xx work
 correctly by design rather than by accident.
 
 "mm: remove arch_make_page_accessible()" from David Hildenbrand.  Some
 folio conversions which make arch_make_page_accessible() unneeded.
 
 "mm, memcg: cg2 memory{.swap,}.peak write handlers" fro David Finkel.
 Cleans up and fixes our handling of the resetting of the cgroup/process
 peak-memory-use detector.
 
 "Make core VMA operations internal and testable" from Lorenzo Stoakes.
 Rationalizaion and encapsulation of the VMA manipulation APIs.  With a
 view to better enable testing of the VMA functions, even from a
 userspace-only harness.
 
 "mm: zswap: fixes for global shrinker" from Takero Funaki.  Fix issues in
 the zswap global shrinker, resulting in improved performance.
 
 "mm: print the promo watermark in zoneinfo" from Kaiyang Zhao.  Fill in
 some missing info in /proc/zoneinfo.
 
 "mm: replace follow_page() by folio_walk" from David Hildenbrand.  Code
 cleanups and rationalizations (conversion to folio_walk()) resulting in
 the removal of follow_page().
 
 "improving dynamic zswap shrinker protection scheme" from Nhat Pham.  Some
 tuning to improve zswap's dynamic shrinker.  Significant reductions in
 swapin and improvements in performance are shown.
 
 "mm: Fix several issues with unaccepted memory" from Kirill Shutemov.
 Improvements to the new unaccepted memory feature,
 
 "mm/mprotect: Fix dax puds" from Peter Xu.  Implements mprotect on DAX
 PUDs.  This was missing, although nobody seems to have notied yet.
 
 "Introduce a store type enum for the Maple tree" from Sidhartha Kumar.
 Cleanups and modest performance improvements for the maple tree library
 code.
 
 "memcg: further decouple v1 code from v2" from Shakeel Butt.  Move more
 cgroup v1 remnants away from the v2 memcg code.
 
 "memcg: initiate deprecation of v1 features" from Shakeel Butt.  Adds
 various warnings telling users that memcg v1 features are deprecated.
 
 "mm: swap: mTHP swap allocator base on swap cluster order" from Chris Li.
 Greatly improves the success rate of the mTHP swap allocation.
 
 "mm: introduce numa_memblks" from Mike Rapoport.  Moves various disparate
 per-arch implementations of numa_memblk code into generic code.
 
 "mm: batch free swaps for zap_pte_range()" from Barry Song.  Greatly
 improves the performance of munmap() of swap-filled ptes.
 
 "support large folio swap-out and swap-in for shmem" from Baolin Wang.
 With this series we no longer split shmem large folios into simgle-page
 folios when swapping out shmem.
 
 "mm/hugetlb: alloc/free gigantic folios" from Yu Zhao.  Nice performance
 improvements and code reductions for gigantic folios.
 
 "support shmem mTHP collapse" from Baolin Wang.  Adds support for
 khugepaged's collapsing of shmem mTHP folios.
 
 "mm: Optimize mseal checks" from Pedro Falcato.  Fixes an mprotect()
 performance regression due to the addition of mseal().
 
 "Increase the number of bits available in page_type" from Matthew Wilcox.
 Increases the number of bits available in page_type!
 
 "Simplify the page flags a little" from Matthew Wilcox.  Many legacy page
 flags are now folio flags, so the page-based flags and their
 accessors/mutators can be removed.
 
 "mm: store zero pages to be swapped out in a bitmap" from Usama Arif.  An
 optimization which permits us to avoid writing/reading zero-filled zswap
 pages to backing store.
 
 "Avoid MAP_FIXED gap exposure" from Liam Howlett.  Fixes a race window
 which occurs when a MAP_FIXED operqtion is occurring during an unrelated
 vma tree walk.
 
 "mm: remove vma_merge()" from Lorenzo Stoakes.  Major rotorooting of the
 vma_merge() functionality, making ot cleaner, more testable and better
 tested.
 
 "misc fixups for DAMON {self,kunit} tests" from SeongJae Park.  Minor
 fixups of DAMON selftests and kunit tests.
 
 "mm: memory_hotplug: improve do_migrate_range()" from Kefeng Wang.  Code
 cleanups and folio conversions.
 
 "Shmem mTHP controls and stats improvements" from Ryan Roberts.  Cleanups
 for shmem controls and stats.
 
 "mm: count the number of anonymous THPs per size" from Barry Song.  Expose
 additional anon THP stats to userspace for improved tuning.
 
 "mm: finish isolate/putback_lru_page()" from Kefeng Wang: more folio
 conversions and removal of now-unused page-based APIs.
 
 "replace per-quota region priorities histogram buffer with per-context
 one" from SeongJae Park.  DAMON histogram rationalization.
 
 "Docs/damon: update GitHub repo URLs and maintainer-profile" from SeongJae
 Park.  DAMON documentation updates.
 
 "mm/vdpa: correct misuse of non-direct-reclaim __GFP_NOFAIL and improve
 related doc and warn" from Jason Wang: fixes usage of page allocator
 __GFP_NOFAIL and GFP_ATOMIC flags.
 
 "mm: split underused THPs" from Yu Zhao.  Improve THP=always policy - this
 was overprovisioning THPs in sparsely accessed memory areas.
 
 "zram: introduce custom comp backends API" frm Sergey Senozhatsky.  Add
 support for zram run-time compression algorithm tuning.
 
 "mm: Care about shadow stack guard gap when getting an unmapped area" from
 Mark Brown.  Fix up the various arch_get_unmapped_area() implementations
 to better respect guard areas.
 
 "Improve mem_cgroup_iter()" from Kinsey Ho.  Improve the reliability of
 mem_cgroup_iter() and various code cleanups.
 
 "mm: Support huge pfnmaps" from Peter Xu.  Extends the usage of huge
 pfnmap support.
 
 "resource: Fix region_intersects() vs add_memory_driver_managed()" from
 Huang Ying.  Fix a bug in region_intersects() for systems with CXL memory.
 
 "mm: hwpoison: two more poison recovery" from Kefeng Wang.  Teaches a
 couple more code paths to correctly recover from the encountering of
 poisoned memry.
 
 "mm: enable large folios swap-in support" from Barry Song.  Support the
 swapin of mTHP memory into appropriately-sized folios, rather than into
 single-page folios.
 -----BEGIN PGP SIGNATURE-----
 
 iHUEABYIAB0WIQTTMBEPP41GrTpTJgfdBJ7gKXxAjgUCZu1BBwAKCRDdBJ7gKXxA
 jlWNAQDYlqQLun7bgsAN4sSvi27VUuWv1q70jlMXTfmjJAvQqwD/fBFVR6IOOiw7
 AkDbKWP2k0hWPiNJBGwoqxdHHx09Xgo=
 =s0T+
 -----END PGP SIGNATURE-----

Merge tag 'mm-stable-2024-09-20-02-31' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull MM updates from Andrew Morton:
 "Along with the usual shower of singleton patches, notable patch series
  in this pull request are:

   - "Align kvrealloc() with krealloc()" from Danilo Krummrich. Adds
     consistency to the APIs and behaviour of these two core allocation
     functions. This also simplifies/enables Rustification.

   - "Some cleanups for shmem" from Baolin Wang. No functional changes -
     mode code reuse, better function naming, logic simplifications.

   - "mm: some small page fault cleanups" from Josef Bacik. No
     functional changes - code cleanups only.

   - "Various memory tiering fixes" from Zi Yan. A small fix and a
     little cleanup.

   - "mm/swap: remove boilerplate" from Yu Zhao. Code cleanups and
     simplifications and .text shrinkage.

   - "Kernel stack usage histogram" from Pasha Tatashin and Shakeel
     Butt. This is a feature, it adds new feilds to /proc/vmstat such as

       $ grep kstack /proc/vmstat
       kstack_1k 3
       kstack_2k 188
       kstack_4k 11391
       kstack_8k 243
       kstack_16k 0

     which tells us that 11391 processes used 4k of stack while none at
     all used 16k. Useful for some system tuning things, but
     partivularly useful for "the dynamic kernel stack project".

   - "kmemleak: support for percpu memory leak detect" from Pavel
     Tikhomirov. Teaches kmemleak to detect leaksage of percpu memory.

   - "mm: memcg: page counters optimizations" from Roman Gushchin. "3
     independent small optimizations of page counters".

   - "mm: split PTE/PMD PT table Kconfig cleanups+clarifications" from
     David Hildenbrand. Improves PTE/PMD splitlock detection, makes
     powerpc/8xx work correctly by design rather than by accident.

   - "mm: remove arch_make_page_accessible()" from David Hildenbrand.
     Some folio conversions which make arch_make_page_accessible()
     unneeded.

   - "mm, memcg: cg2 memory{.swap,}.peak write handlers" fro David
     Finkel. Cleans up and fixes our handling of the resetting of the
     cgroup/process peak-memory-use detector.

   - "Make core VMA operations internal and testable" from Lorenzo
     Stoakes. Rationalizaion and encapsulation of the VMA manipulation
     APIs. With a view to better enable testing of the VMA functions,
     even from a userspace-only harness.

   - "mm: zswap: fixes for global shrinker" from Takero Funaki. Fix
     issues in the zswap global shrinker, resulting in improved
     performance.

   - "mm: print the promo watermark in zoneinfo" from Kaiyang Zhao. Fill
     in some missing info in /proc/zoneinfo.

   - "mm: replace follow_page() by folio_walk" from David Hildenbrand.
     Code cleanups and rationalizations (conversion to folio_walk())
     resulting in the removal of follow_page().

   - "improving dynamic zswap shrinker protection scheme" from Nhat
     Pham. Some tuning to improve zswap's dynamic shrinker. Significant
     reductions in swapin and improvements in performance are shown.

   - "mm: Fix several issues with unaccepted memory" from Kirill
     Shutemov. Improvements to the new unaccepted memory feature,

   - "mm/mprotect: Fix dax puds" from Peter Xu. Implements mprotect on
     DAX PUDs. This was missing, although nobody seems to have notied
     yet.

   - "Introduce a store type enum for the Maple tree" from Sidhartha
     Kumar. Cleanups and modest performance improvements for the maple
     tree library code.

   - "memcg: further decouple v1 code from v2" from Shakeel Butt. Move
     more cgroup v1 remnants away from the v2 memcg code.

   - "memcg: initiate deprecation of v1 features" from Shakeel Butt.
     Adds various warnings telling users that memcg v1 features are
     deprecated.

   - "mm: swap: mTHP swap allocator base on swap cluster order" from
     Chris Li. Greatly improves the success rate of the mTHP swap
     allocation.

   - "mm: introduce numa_memblks" from Mike Rapoport. Moves various
     disparate per-arch implementations of numa_memblk code into generic
     code.

   - "mm: batch free swaps for zap_pte_range()" from Barry Song. Greatly
     improves the performance of munmap() of swap-filled ptes.

   - "support large folio swap-out and swap-in for shmem" from Baolin
     Wang. With this series we no longer split shmem large folios into
     simgle-page folios when swapping out shmem.

   - "mm/hugetlb: alloc/free gigantic folios" from Yu Zhao. Nice
     performance improvements and code reductions for gigantic folios.

   - "support shmem mTHP collapse" from Baolin Wang. Adds support for
     khugepaged's collapsing of shmem mTHP folios.

   - "mm: Optimize mseal checks" from Pedro Falcato. Fixes an mprotect()
     performance regression due to the addition of mseal().

   - "Increase the number of bits available in page_type" from Matthew
     Wilcox. Increases the number of bits available in page_type!

   - "Simplify the page flags a little" from Matthew Wilcox. Many legacy
     page flags are now folio flags, so the page-based flags and their
     accessors/mutators can be removed.

   - "mm: store zero pages to be swapped out in a bitmap" from Usama
     Arif. An optimization which permits us to avoid writing/reading
     zero-filled zswap pages to backing store.

   - "Avoid MAP_FIXED gap exposure" from Liam Howlett. Fixes a race
     window which occurs when a MAP_FIXED operqtion is occurring during
     an unrelated vma tree walk.

   - "mm: remove vma_merge()" from Lorenzo Stoakes. Major rotorooting of
     the vma_merge() functionality, making ot cleaner, more testable and
     better tested.

   - "misc fixups for DAMON {self,kunit} tests" from SeongJae Park.
     Minor fixups of DAMON selftests and kunit tests.

   - "mm: memory_hotplug: improve do_migrate_range()" from Kefeng Wang.
     Code cleanups and folio conversions.

   - "Shmem mTHP controls and stats improvements" from Ryan Roberts.
     Cleanups for shmem controls and stats.

   - "mm: count the number of anonymous THPs per size" from Barry Song.
     Expose additional anon THP stats to userspace for improved tuning.

   - "mm: finish isolate/putback_lru_page()" from Kefeng Wang: more
     folio conversions and removal of now-unused page-based APIs.

   - "replace per-quota region priorities histogram buffer with
     per-context one" from SeongJae Park. DAMON histogram
     rationalization.

   - "Docs/damon: update GitHub repo URLs and maintainer-profile" from
     SeongJae Park. DAMON documentation updates.

   - "mm/vdpa: correct misuse of non-direct-reclaim __GFP_NOFAIL and
     improve related doc and warn" from Jason Wang: fixes usage of page
     allocator __GFP_NOFAIL and GFP_ATOMIC flags.

   - "mm: split underused THPs" from Yu Zhao. Improve THP=always policy.
     This was overprovisioning THPs in sparsely accessed memory areas.

   - "zram: introduce custom comp backends API" frm Sergey Senozhatsky.
     Add support for zram run-time compression algorithm tuning.

   - "mm: Care about shadow stack guard gap when getting an unmapped
     area" from Mark Brown. Fix up the various arch_get_unmapped_area()
     implementations to better respect guard areas.

   - "Improve mem_cgroup_iter()" from Kinsey Ho. Improve the reliability
     of mem_cgroup_iter() and various code cleanups.

   - "mm: Support huge pfnmaps" from Peter Xu. Extends the usage of huge
     pfnmap support.

   - "resource: Fix region_intersects() vs add_memory_driver_managed()"
     from Huang Ying. Fix a bug in region_intersects() for systems with
     CXL memory.

   - "mm: hwpoison: two more poison recovery" from Kefeng Wang. Teaches
     a couple more code paths to correctly recover from the encountering
     of poisoned memry.

   - "mm: enable large folios swap-in support" from Barry Song. Support
     the swapin of mTHP memory into appropriately-sized folios, rather
     than into single-page folios"

* tag 'mm-stable-2024-09-20-02-31' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (416 commits)
  zram: free secondary algorithms names
  uprobes: turn xol_area->pages[2] into xol_area->page
  uprobes: introduce the global struct vm_special_mapping xol_mapping
  Revert "uprobes: use vm_special_mapping close() functionality"
  mm: support large folios swap-in for sync io devices
  mm: add nr argument in mem_cgroup_swapin_uncharge_swap() helper to support large folios
  mm: fix swap_read_folio_zeromap() for large folios with partial zeromap
  mm/debug_vm_pgtable: Use pxdp_get() for accessing page table entries
  set_memory: add __must_check to generic stubs
  mm/vma: return the exact errno in vms_gather_munmap_vmas()
  memcg: cleanup with !CONFIG_MEMCG_V1
  mm/show_mem.c: report alloc tags in human readable units
  mm: support poison recovery from copy_present_page()
  mm: support poison recovery from do_cow_fault()
  resource, kunit: add test case for region_intersects()
  resource: make alloc_free_mem_region() works for iomem_resource
  mm: z3fold: deprecate CONFIG_Z3FOLD
  vfio/pci: implement huge_fault support
  mm/arm64: support large pfn mappings
  mm/x86: support large pfn mappings
  ...
2024-09-21 07:29:05 -07:00
Linus Torvalds
2004cef11e In the v6.12 scheduler development cycle we had 63 commits from 18 contributors:
- Implement the SCHED_DEADLINE server infrastructure - Daniel Bristot de Oliveira's
    last major contribution to the kernel:
 
      "SCHED_DEADLINE servers can help fixing starvation issues of low priority
      tasks (e.g., SCHED_OTHER) when higher priority tasks monopolize CPU
      cycles. Today we have RT Throttling; DEADLINE servers should be able to
      replace and improve that."
 
      (Daniel Bristot de Oliveira, Peter Zijlstra, Joel Fernandes,
       Youssef Esmat, Huang Shijie)
 
  - Preparatory changes for sched_ext integration:
 
      - Use set_next_task(.first) where required
      - Fix up set_next_task() implementations
      - Clean up DL server vs. core sched
      - Split up put_prev_task_balance()
      - Rework pick_next_task()
      - Combine the last put_prev_task() and the first set_next_task()
      - Rework dl_server
      - Add put_prev_task(.next)
 
       (Peter Zijlstra, with a fix by Tejun Heo)
 
  - Complete the EEVDF transition and refine EEVDF scheduling:
 
      - Implement delayed dequeue
      - Allow shorter slices to wakeup-preempt
      - Use sched_attr::sched_runtime to set request/slice suggestion
      - Document the new feature flags
      - Remove unused and duplicate-functionality fields
      - Simplify & unify pick_next_task_fair()
      - Misc debuggability enhancements
 
       (Peter Zijlstra, with fixes/cleanups by Dietmar Eggemann,
        Valentin Schneider and Chuyi Zhou)
 
  - Initialize the vruntime of a new task when it is first enqueued,
    resulting in significant decrease in latency of newly woken tasks.
    (Zhang Qiao)
 
  - Introduce SM_IDLE and an idle re-entry fast-path in __schedule()
    (K Prateek Nayak, Peter Zijlstra)
 
  - Clean up and clarify the usage of Clean up usage of rt_task()
    (Qais Yousef)
 
  - Preempt SCHED_IDLE entities in strict cgroup hierarchies
    (Tianchen Ding)
 
  - Clarify the documentation of time units for deadline scheduler
    parameters. (Christian Loehle)
 
  - Remove the HZ_BW chicken-bit feature flag introduced a year ago,
    the original change seems to be working fine.
    (Phil Auld)
 
  - Misc fixes and cleanups (Chen Yu, Dan Carpenter, Huang Shijie,
    Peilin He, Qais Yousefm and Vincent Guittot)
 
 Signed-off-by: Ingo Molnar <mingo@kernel.org>
 -----BEGIN PGP SIGNATURE-----
 
 iQJFBAABCgAvFiEEBpT5eoXrXCwVQwEKEnMQ0APhK1gFAmbr8qcRHG1pbmdvQGtl
 cm5lbC5vcmcACgkQEnMQ0APhK1gdbw/+Mj3zWfYP+dtUkfgrR2FClPAJoo1/9Dz0
 LYD8XgYHu8rEJ0Aq+VbdkgYGUt9utvzUFPIxvWFDcldQl57KwhF4hp9Ir+PqJyYC
 NolQ1q8ddo1hnslxnEg6SgHVzQq/4FqMM0nDNUkQETCx6zTyFFeRf+q7o/2c2m5B
 uI9dSU1Wrx7XrXm2D3kB8+xP+ZRy+qhbFN5Pfuz96mhelfklylgKMfPzgAiCT/7T
 JTbQhQ2HdcCNgiLoSrWsHBDy2UYpouP4zb4jyd+lDQzhSUJrj3u4Xy4vVmuTKq+y
 sTgWlgKB+MTuh9UuJ4UYzSnMqg161UlMvtXeH84ABmAqDNGHRPtOKrrlcLtJ3D4x
 m1SPhNnsvpjOu2pH0XLIS8al3VUesWND5S+rucHRYSq6Nvhivf4MTvRJlicXXurL
 Mt2APnIlhGJuKBNWnmyZovVdtO0ZUUPlaZWfr3rCS4txAVo+HwWhsm3uhtTycQqN
 gazsCiuGh6Jds90ZqA/BvdLWG+DY8J0xLlV3ex4pCXuQ/HFrabVWTyThJsULhrZ2
 5mTdWIsocPctNMO9/RHMy7vJI7G7ljgHEquWVn5kiGGzXhK6VwVwKAMpfgXGw+YA
 yVP6/M7a7g2yEzj69gXkcDa8k/kedMVquJ/G/8YhZM7u7sPqsMjpmaGsqsJRfnpT
 ChngAzap+kA=
 =TEC6
 -----END PGP SIGNATURE-----

Merge tag 'sched-core-2024-09-19' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull scheduler updates from Ingo Molnar:

 - Implement the SCHED_DEADLINE server infrastructure - Daniel Bristot
   de Oliveira's last major contribution to the kernel:

     "SCHED_DEADLINE servers can help fixing starvation issues of low
      priority tasks (e.g., SCHED_OTHER) when higher priority tasks
      monopolize CPU cycles. Today we have RT Throttling; DEADLINE
      servers should be able to replace and improve that."

   (Daniel Bristot de Oliveira, Peter Zijlstra, Joel Fernandes, Youssef
   Esmat, Huang Shijie)

 - Preparatory changes for sched_ext integration:
     - Use set_next_task(.first) where required
     - Fix up set_next_task() implementations
     - Clean up DL server vs. core sched
     - Split up put_prev_task_balance()
     - Rework pick_next_task()
     - Combine the last put_prev_task() and the first set_next_task()
     - Rework dl_server
     - Add put_prev_task(.next)

   (Peter Zijlstra, with a fix by Tejun Heo)

 - Complete the EEVDF transition and refine EEVDF scheduling:
     - Implement delayed dequeue
     - Allow shorter slices to wakeup-preempt
     - Use sched_attr::sched_runtime to set request/slice suggestion
     - Document the new feature flags
     - Remove unused and duplicate-functionality fields
     - Simplify & unify pick_next_task_fair()
     - Misc debuggability enhancements

   (Peter Zijlstra, with fixes/cleanups by Dietmar Eggemann, Valentin
   Schneider and Chuyi Zhou)

 - Initialize the vruntime of a new task when it is first enqueued,
   resulting in significant decrease in latency of newly woken tasks
   (Zhang Qiao)

 - Introduce SM_IDLE and an idle re-entry fast-path in __schedule()
   (K Prateek Nayak, Peter Zijlstra)

 - Clean up and clarify the usage of Clean up usage of rt_task()
   (Qais Yousef)

 - Preempt SCHED_IDLE entities in strict cgroup hierarchies
   (Tianchen Ding)

 - Clarify the documentation of time units for deadline scheduler
   parameters (Christian Loehle)

 - Remove the HZ_BW chicken-bit feature flag introduced a year ago,
   the original change seems to be working fine (Phil Auld)

 - Misc fixes and cleanups (Chen Yu, Dan Carpenter, Huang Shijie,
   Peilin He, Qais Yousefm and Vincent Guittot)

* tag 'sched-core-2024-09-19' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (64 commits)
  sched/cpufreq: Use NSEC_PER_MSEC for deadline task
  cpufreq/cppc: Use NSEC_PER_MSEC for deadline task
  sched/deadline: Clarify nanoseconds in uapi
  sched/deadline: Convert schedtool example to chrt
  sched/debug: Fix the runnable tasks output
  sched: Fix sched_delayed vs sched_core
  kernel/sched: Fix util_est accounting for DELAY_DEQUEUE
  kthread: Fix task state in kthread worker if being frozen
  sched/pelt: Use rq_clock_task() for hw_pressure
  sched/fair: Move effective_cpu_util() and effective_cpu_util() in fair.c
  sched/core: Introduce SM_IDLE and an idle re-entry fast-path in __schedule()
  sched: Add put_prev_task(.next)
  sched: Rework dl_server
  sched: Combine the last put_prev_task() and the first set_next_task()
  sched: Rework pick_next_task()
  sched: Split up put_prev_task_balance()
  sched: Clean up DL server vs core sched
  sched: Fixup set_next_task() implementations
  sched: Use set_next_task(.first) where required
  sched/fair: Properly deactivate sched_delayed task upon class change
  ...
2024-09-19 15:55:58 +02:00
Linus Torvalds
4a39ac5b7d Random number generator updates for Linux 6.12-rc1.
-----BEGIN PGP SIGNATURE-----
 
 iQIzBAABCAAdFiEEq5lC5tSkz8NBJiCnSfxwEqXeA64FAmboHyUACgkQSfxwEqXe
 A66wGQ/8DRIjBllwf1YuTWi4T6OcfoYxK6C9bXO6QPP5gzdTyFE9pvDuuPyad6+F
 FR086ydTHeodemz1dFiQCL9etcUaxo4+6FRKyXKF9/1ezGbTA5nJd0/fKJGlqbI2
 EoA4LNYHOsvCZk1BTpxRNWKeKphU9zQgQdSigy6Rx8p269UkGmIZjD1PtUc+vqfR
 Ox0dK/Cswyo236fRi5HzaoMntWI4vXgLfxty0e1R7tfbstkCxSKWAON1lo3uHgkA
 0HpJXWgWXAPt9gp++Fs/jGNpOqbt6IaKeV5f7CjYfvWhlFjNMhQxF+PbxknaZn/k
 K0gQsItOIoFTfbQdLDIdfnj9awMdLW8FB2A1WXHpNr9pVC4ickPb1bMTF/XRd0tm
 wBNu4BL0gklx6017KZg5uINMIduzMLGkBLRFiBW0en/sZMLTJTMg58BJn0CL1Pmh
 1ll/Q3ToSMHalvxU2OnJagTwh4fzzCEpK/hW9WiDO4jSCsMXyX0clinrCjNo1JfA
 tqgTWEy3uGtg+dg0Du9VD5JASbNQSJ0ZRnas5+qz10IRWWfTolrsk61dliXLQ4Sv
 tSryDtsE2znwJF1Krh4aHNSSVhD5/l/8QaXkf9aZc/kkaHxwsx83FuWnqw6nMz8c
 l4B2MbH0jUgsEqEyx+0iwk+FXE9kZKWumTVLjFZ6bRnq3q+uq0U=
 =mWCw
 -----END PGP SIGNATURE-----

Merge tag 'random-6.12-rc1-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/crng/random

Pull random number generator updates from Jason Donenfeld:
 "Originally I'd planned on sending each of the vDSO getrandom()
  architecture ports to their respective arch trees. But as we started
  to work on this, we found lots of interesting issues in the shared
  code and infrastructure, the fixes for which the various archs needed
  to base their work.

  So in the end, this turned into a nice collaborative effort fixing up
  issues and porting to 5 new architectures -- arm64, powerpc64,
  powerpc32, s390x, and loongarch64 -- with everybody pitching in and
  commenting on each other's code. It was a fun development cycle.

  This contains:

   - Numerous fixups to the vDSO selftest infrastructure, getting it
     running successfully on more platforms, and fixing bugs in it.

   - Additions to the vDSO getrandom & chacha selftests. Basically every
     time manual review unearthed a bug in a revision of an arch patch,
     or an ambiguity, the tests were augmented.

     By the time the last arch was submitted for review, s390x, v1 of
     the series was essentially fine right out of the gate.

   - Fixes to the the generic C implementation of vDSO getrandom, to
     build and run successfully on all archs, decoupling it from
     assumptions we had (unintentionally) made on x86_64 that didn't
     carry through to the other architectures.

   - Port of vDSO getrandom to LoongArch64, from Xi Ruoyao and acked by
     Huacai Chen.

   - Port of vDSO getrandom to ARM64, from Adhemerval Zanella and acked
     by Will Deacon.

   - Port of vDSO getrandom to PowerPC, in both 32-bit and 64-bit
     varieties, from Christophe Leroy and acked by Michael Ellerman.

   - Port of vDSO getrandom to S390X from Heiko Carstens, the arch
     maintainer.

  While it'd be natural for there to be things to fix up over the course
  of the development cycle, these patches got a decent amount of review
  from a fairly diverse crew of folks on the mailing lists, and, for the
  most part, they've been cooking in linux-next, which has been helpful
  for ironing out build issues.

  In terms of architectures, I think that mostly takes care of the
  important 64-bit archs with hardware still being produced and running
  production loads in settings where vDSO getrandom is likely to help.

  Arguably there's still RISC-V left, and we'll see for 6.13 whether
  they find it useful and submit a port"

* tag 'random-6.12-rc1-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/crng/random: (47 commits)
  selftests: vDSO: check cpu caps before running chacha test
  s390/vdso: Wire up getrandom() vdso implementation
  s390/vdso: Move vdso symbol handling to separate header file
  s390/vdso: Allow alternatives in vdso code
  s390/module: Provide find_section() helper
  s390/facility: Let test_facility() generate static branch if possible
  s390/alternatives: Remove ALT_FACILITY_EARLY
  s390/facility: Disable compile time optimization for decompressor code
  selftests: vDSO: fix vdso_config for s390
  selftests: vDSO: fix ELF hash table entry size for s390x
  powerpc/vdso: Wire up getrandom() vDSO implementation on VDSO64
  powerpc/vdso: Wire up getrandom() vDSO implementation on VDSO32
  powerpc/vdso: Refactor CFLAGS for CVDSO build
  powerpc/vdso32: Add crtsavres
  mm: Define VM_DROPPABLE for powerpc/32
  powerpc/vdso: Fix VDSO data access when running in a non-root time namespace
  selftests: vDSO: don't include generated headers for chacha test
  arm64: vDSO: Wire up getrandom() vDSO implementation
  arm64: alternative: make alternative_has_cap_likely() VDSO compatible
  selftests: vDSO: also test counter in vdso_test_chacha
  ...
2024-09-18 15:26:31 +02:00
Alexey Dobriyan
1330976472 proc: use __auto_type more
Switch away from quite chatty declarations using typeof_member().

In theory this is faster to compile too because there is no macro
expansion and there is less type checking.

Link: https://lkml.kernel.org/r/81bf02fd-8724-4f4d-a2bb-c59620b7d716@p183
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-17 01:11:20 -07:00
Linus Torvalds
c903327d32 printk changes for 6.12
-----BEGIN PGP SIGNATURE-----
 
 iQIzBAABCAAdFiEESH4wyp42V4tXvYsjUqAMR0iAlPIFAmbi598ACgkQUqAMR0iA
 lPL3lw//WaRDKJ1Cb/bKAn3nRpjdqiNBI//K1gRJp0LgLE7qEudE25t4j3F9tvvP
 pc9AB81g1Au8Br6iOd+NiGXXW5KWJHaZ3rUAdeo6co4NQCbrY6qTA78ItZSQImBH
 A9fhWWr1TGRX8L/N/gR2eYBnpbDGIbRahUOQraUpBn4kEPyR47KEx7Njjo48GcmR
 Ye8dIYwUOWEgQeIuIxIAwNf6KyNjo5tQpgve+M8HGwy8mZqP9XV6UjXUACVwQNx6
 +CK+IGM+94tCq5KalOaJ5BtsXGKlabHIs7y9QpLS45M2QoHIlDIvpaxzLf0FTsPI
 CppqedAGN2jU0NyjfbFk1c+SNQfDZEAZVyF6vKFelP7t2jzAx301RyB2S+Cm7Hh+
 PajFty41UT0/y17V4sZawfMqpFyp7Wr6RKQYYKMBRdSQQkToh/dmebBvqPAHW9cJ
 LInQQf+XdzbonKa+CTmT/Tg+eM2R124FWeMVnEMdtyXpKUV9qdKWfngtzyRMQiYI
 q54ZwKd3VJ9kRIfb7Fp0TBr2NErdnEQE5hh9QhI8SAWENskw5+GmYaQit734U9wA
 SU7t9rir7NS4Rc1jHP9SQ9oWWI9HT4hthRGkLh2Knx0O2c6AwOuEI4wkjzSWI3GX
 /eeofnbZiUpi7fESf9qmTGtQZ4/9ogQ7fNaroWCSfQzq3+wl+2o=
 =28sV
 -----END PGP SIGNATURE-----

Merge tag 'printk-for-6.12' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux

Pull printk updates from Petr Mladek:
 "This is the "last" part of the support for the new nbcon consoles.
  Where "nbcon" stays for "No Big console lock CONsoles" aka not under
  the console_lock.

  New callbacks are added to struct console:

   - write_thread() for flushing nbcon consoles in task context.

   - write_atomic() for flushing nbcon consoles in atomic context,
     including NMI.

   - con->device_lock() and device_unlock() for taking the driver
     specific lock, for example, port->lock.

  New printk-specific kthreads are created:

   - per-console kthreads which get responsible for flushing normal
     priority messages on nbcon consoles.

   - thread which gets responsible for flushing normal priority messages
     on all consoles when CONFIG_RT enabled.

  The new callbacks are called under a special per-console lock which
  has already been added back in v6.7. It allows to distinguish three
  severities: normal, emergency, and panic. A context with a higher
  priority could take over the ownership when it is safe even in the
  middle of handling a record. The panic context could do it even when
  it is not safe. But it is allowed only for the final desperate flush
  before entering the infinite loop.

  The new lock helps to flush the messages directly in emergency and
  panic contexts. But it is not enough in all situations:

   - console_lock() is still need for synchronization against boot
     consoles.

   - con->device_lock() is need for synchronization against other
     operations on the same HW, e.g. serial port speed setting,
     non-printk related read/write.

  The dependency on con->device_lock() is mutual. Any code taking the
  driver specific lock has to acquire the related nbcon console context
  as well. For example, see the new uart_port_lock() API. It provides
  the necessary synchronization against emergency and panic contexts
  where the messages are flushed only under the new per-console lock.

  Maybe surprisingly, a quite tricky part is the decision how to flush
  the consoles in various situations. It has to take into account:

   - message priority:    normal, emergency, panic

   - scheduling context:  task, atomic, deferred_legacy

   - registered consoles: boot, legacy, nbcon

   - threads are running: early boot, suspend, shutdown, panic

   - caller:              printk(), pr_flush(), printk_flush_in_panic(),
                          console_unlock(), console_start(), ...

  The primary decision is made in printk_get_console_flush_type(). It
  creates a hint what the caller should do:

   - flush nbcon consoles directly or via the kthread

   - call the legacy loop (console_unlock()) directly or via irq_work

  The existing behavior is preserved for the legacy consoles. The only
  exception is that they are not longer flushed directly from printk()
  in panic() before CPUs are stopped. But this blocking happens only
  when at least one nbcon console is registered. The motivation is to
  increase a chance to produce the crash dump. They legacy consoles
  might create a deadlock in compare with nbcon consoles. The nbcon
  console should allow to see the messages even when the crash dump
  fails.

  There are three possible ways how nbcon consoles are flushed:

   - The per-nbcon-console kthread is responsible for flushing messages
     added with the normal priority. This is the default mode.

   - The legacy loop, aka console_unlock(), is used when there is still
     a boot console registered. There is no easy way how to match an
     early console driver with a nbcon console driver. And the
     console_lock() provides the only reliable serialization at the
     moment.

     The legacy loop uses either con->write_atomic() or
     con->write_thread() callbacks depending on whether it is allowed to
     schedule. The atomic variant has to be used from printk().

   - In other situations, the messages are flushed directly using
     write_atomic() which can be called in any context, including NMI.
     It is primary needed during early boot or shutdown, in emergency
     situations, and panic.

  The emergency priority is used by a code called within
  nbcon_cpu_emergency_enter()/exit(). At the moment, it is used in four
  situations: WARN(), Oops, lockdep, and RCU stall reports.

  Finally, there is no nbcon console at the moment. It means that the
  changes should _not_ modify the existing behavior. The only exception
  is CONFIG_RT which would force offloading the legacy loop, for normal
  priority context, into the dedicated kthread"

* tag 'printk-for-6.12' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux: (54 commits)
  printk: Avoid false positive lockdep report for legacy printing
  printk: nbcon: Assign nice -20 for printing threads
  printk: Implement legacy printer kthread for PREEMPT_RT
  tty: sysfs: Add nbcon support for 'active'
  proc: Add nbcon support for /proc/consoles
  proc: consoles: Add notation to c_start/c_stop
  printk: nbcon: Show replay message on takeover
  printk: Provide helper for message prepending
  printk: nbcon: Rely on kthreads for normal operation
  printk: nbcon: Use thread callback if in task context for legacy
  printk: nbcon: Relocate nbcon_atomic_emit_one()
  printk: nbcon: Introduce printer kthreads
  printk: nbcon: Init @nbcon_seq to highest possible
  printk: nbcon: Add context to usable() and emit()
  printk: Flush console on unregister_console()
  printk: Fail pr_flush() if before SYSTEM_SCHEDULING
  printk: nbcon: Add function for printers to reacquire ownership
  printk: nbcon: Use raw_cpu_ptr() instead of open coding
  printk: Use the BITS_PER_LONG macro
  lockdep: Mark emergency sections in lockdep splats
  ...
2024-09-17 08:52:28 +02:00
Linus Torvalds
9ea925c806 Updates for timers and timekeeping:
- Core:
 
 	- Overhaul of posix-timers in preparation of removing the
 	  workaround for periodic timers which have signal delivery
 	  ignored.
 
         - Remove the historical extra jiffie in msleep()
 
 	  msleep() adds an extra jiffie to the timeout value to ensure
 	  minimal sleep time. The timer wheel ensures minimal sleep
 	  time since the large rewrite to a non-cascading wheel, but the
 	  extra jiffie in msleep() remained unnoticed. Remove it.
 
         - Make the timer slack handling correct for realtime tasks.
 
 	  The procfs interface is inconsistent and does neither reflect
 	  reality nor conforms to the man page. Show the correct 0 slack
 	  for real time tasks and enforce it at the core level instead of
 	  having inconsistent individual checks in various timer setup
 	  functions.
 
         - The usual set of updates and enhancements all over the place.
 
   - Drivers:
 
         - Allow the ACPI PM timer to be turned off during suspend
 
 	- No new drivers
 
 	- The usual updates and enhancements in various drivers
 -----BEGIN PGP SIGNATURE-----
 
 iQJHBAABCgAxFiEEQp8+kY+LLUocC4bMphj1TA10mKEFAmbn7jQTHHRnbHhAbGlu
 dXRyb25peC5kZQAKCRCmGPVMDXSYobqnD/9COlU0nwsulABI/aNIrsh6iYvnCC9v
 14CcNta7Qn+157Wfw9BWOyHdNhR1/fPCXE8jJ71zTyIOeW27HV2JyTtxTwe9ZcdK
 ViHAaj7YcIjcVUEC3StCoRCPnvLslEw4qJA5AOQuDyMivdQn+YVa2c0baJxKaXZt
 xk4HZdMj4NAS0jRKnoZSwtKW/+Oz6rR4GAWrZo+Zs1/8ur3HfqnQfi8lJ1hJtLLW
 V7XDCVRvamVi6Ah3ocYPPp/1P6yeQDA1ge9aMddqaza5STWISXRtSnFMUmYP3rbS
 FaL8TyL+ilfny8pkGB2WlG6nLuSbtvogtdEh1gG1k1RmZt44kAtk8ba/KiWFPBSb
 zK9cjojRMBS71f9G4kmb5F4rnXoLsg1YbD1Nzhz3wq2Cs1Z90dc2QwMren0zoQ1x
 Fn56ueRyAiagBlnrSaKyso/2RvqJTNoSdi3RkpjYeAph0UoDCqvTvKjGAf1mWiw1
 T/1lUWSVqWHnzZbM7XXzzajIN9bl6A7bbqlcAJ2O9vZIDt7273DG+bQym9Vh6Why
 0LTGGERHxzKBsG7WRg+2Gmvv6S18UPKRo8tLtlA758rHlFuPTZCShWrIriwSNl1K
 Hxon+d4BparSnm1h9W/NHPKJA574UbWRCBjdk58IkAj8DxZZY4ORD9SMP+ggkV7G
 F6p9cgoDNP9KFg==
 =jE0N
 -----END PGP SIGNATURE-----

Merge tag 'timers-core-2024-09-16' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull timer updates from Thomas Gleixner:
 "Core:

   - Overhaul of posix-timers in preparation of removing the workaround
     for periodic timers which have signal delivery ignored.

   - Remove the historical extra jiffie in msleep()

     msleep() adds an extra jiffie to the timeout value to ensure
     minimal sleep time. The timer wheel ensures minimal sleep time
     since the large rewrite to a non-cascading wheel, but the extra
     jiffie in msleep() remained unnoticed. Remove it.

   - Make the timer slack handling correct for realtime tasks.

     The procfs interface is inconsistent and does neither reflect
     reality nor conforms to the man page. Show the correct 0 slack for
     real time tasks and enforce it at the core level instead of having
     inconsistent individual checks in various timer setup functions.

   - The usual set of updates and enhancements all over the place.

  Drivers:

   - Allow the ACPI PM timer to be turned off during suspend

   - No new drivers

   - The usual updates and enhancements in various drivers"

* tag 'timers-core-2024-09-16' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (43 commits)
  ntp: Make sure RTC is synchronized when time goes backwards
  treewide: Fix wrong singular form of jiffies in comments
  cpu: Use already existing usleep_range()
  timers: Rename next_expiry_recalc() to be unique
  platform/x86:intel/pmc: Fix comment for the pmc_core_acpi_pm_timer_suspend_resume function
  clocksource/drivers/jcore: Use request_percpu_irq()
  clocksource/drivers/cadence-ttc: Add missing clk_disable_unprepare in ttc_setup_clockevent
  clocksource/drivers/asm9260: Add missing clk_disable_unprepare in asm9260_timer_init
  clocksource/drivers/qcom: Add missing iounmap() on errors in msm_dt_timer_init()
  clocksource/drivers/ingenic: Use devm_clk_get_enabled() helpers
  platform/x86:intel/pmc: Enable the ACPI PM Timer to be turned off when suspended
  clocksource: acpi_pm: Add external callback for suspend/resume
  clocksource/drivers/arm_arch_timer: Using for_each_available_child_of_node_scoped()
  dt-bindings: timer: rockchip: Add rk3576 compatible
  timers: Annotate possible non critical data race of next_expiry
  timers: Remove historical extra jiffie for timeout in msleep()
  hrtimer: Use and report correct timerslack values for realtime tasks
  hrtimer: Annotate hrtimer_cpu_base_.*_expiry() for sparse.
  timers: Add sparse annotation for timer_sync_wait_running().
  signal: Replace BUG_ON()s
  ...
2024-09-17 07:25:37 +02:00
Linus Torvalds
e8fc317dfc vfs-6.12.procfs
-----BEGIN PGP SIGNATURE-----
 
 iHUEABYKAB0WIQRAhzRXHqcMeLMyaSiRxhvAZXjcogUCZuQEwAAKCRCRxhvAZXjc
 onI2AQDXa5XhIx0VpLWE9uVImVy3QuUKc/5pI1e1DKMgxLhKCgEAh15a4ETqmVaw
 Zp3ZSzoLD8Ez1WwWb6cWQuHFYRSjtwU=
 =+LKG
 -----END PGP SIGNATURE-----

Merge tag 'vfs-6.12.procfs' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull procfs updates from Christian Brauner:
 "This contains the following changes for procfs:

   - Add config options and parameters to block forcing memory writes.

     This adds a Kconfig option and boot param to allow removing the
     FOLL_FORCE flag from /proc/<pid>/mem write calls as this can be
     used in various attacks.

     The traditional forcing behavior is kept as default because it can
     break GDB and some other use cases.

     This is the simpler version that you had requested.

   - Restrict overmounting of ephemeral entities.

     It is currently possible to mount on top of various ephemeral
     entities in procfs. This specifically includes magic links. To
     recap, magic links are links of the form /proc/<pid>/fd/<nr>. They
     serve as references to a target file and during path lookup they
     cause a jump to the target path. Such magic links disappear if the
     corresponding file descriptor is closed.

     Currently it is possible to overmount such magic links. This is
     mostly interesting for an attacker that wants to somehow trick a
     process into e.g., reopening something that it didn't intend to
     reopen or to hide a malicious file descriptor.

     But also it risks leaking mounts for long-running processes. When
     overmounting a magic link like above, the mount will not be
     detached when the file descriptor is closed. Only the target
     mountpoint will disappear. Which has the consequence of making it
     impossible to unmount that mount afterwards. So the mount will
     stick around until the process exits and the /proc/<pid>/ directory
     is cleaned up during proc_flush_pid() when the dentries are pruned
     and invalidated.

     That in turn means it's possible for a program to accidentally leak
     mounts and it's also possible to make a task leak mounts without
     it's knowledge if the attacker just keeps overmounting things under
     /proc/<pid>/fd/<nr>.

     Disallow overmounting of such ephemeral entities.

   - Cleanup the readdir method naming in some procfs file operations.

   - Replace kmalloc() and strcpy() with a simple kmemdup() call"

* tag 'vfs-6.12.procfs' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
  proc: fold kmalloc() + strcpy() into kmemdup()
  proc: block mounting on top of /proc/<pid>/fdinfo/*
  proc: block mounting on top of /proc/<pid>/fd/*
  proc: block mounting on top of /proc/<pid>/map_files/*
  proc: add proc_splice_unmountable()
  proc: proc_readfdinfo() -> proc_fdinfo_iterate()
  proc: proc_readfd() -> proc_fd_iterate()
  proc: add config & param to block forcing mem writes
2024-09-16 09:36:59 +02:00
Linus Torvalds
3352633ce6 vfs-6.12.file
-----BEGIN PGP SIGNATURE-----
 
 iHUEABYKAB0WIQRAhzRXHqcMeLMyaSiRxhvAZXjcogUCZuQEwAAKCRCRxhvAZXjc
 osS0AQCgIpvey9oW5DMyMw6Bv0hFMRv95gbNQZfHy09iK+NMNAD9GALhb/4cMIVB
 7YrZGXEz454lpgcs8AnrOVjVNfctOQg=
 =e9s9
 -----END PGP SIGNATURE-----

Merge tag 'vfs-6.12.file' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull vfs file updates from Christian Brauner:
 "This is the work to cleanup and shrink struct file significantly.

  Right now, (focusing on x86) struct file is 232 bytes. After this
  series struct file will be 184 bytes aka 3 cacheline and a spare 8
  bytes for future extensions at the end of the struct.

  With struct file being as ubiquitous as it is this should make a
  difference for file heavy workloads and allow further optimizations in
  the future.

   - struct fown_struct was embedded into struct file letting it take up
     32 bytes in total when really it shouldn't even be embedded in
     struct file in the first place. Instead, actual users of struct
     fown_struct now allocate the struct on demand. This frees up 24
     bytes.

   - Move struct file_ra_state into the union containg the cleanup hooks
     and move f_iocb_flags out of the union. This closes a 4 byte hole
     we created earlier and brings struct file to 192 bytes. Which means
     struct file is 3 cachelines and we managed to shrink it by 40
     bytes.

   - Reorder struct file so that nothing crosses a cacheline.

     I suspect that in the future we will end up reordering some members
     to mitigate false sharing issues or just because someone does
     actually provide really good perf data.

   - Shrinking struct file to 192 bytes is only part of the work.

     Files use a slab that is SLAB_TYPESAFE_BY_RCU and when a kmem cache
     is created with SLAB_TYPESAFE_BY_RCU the free pointer must be
     located outside of the object because the cache doesn't know what
     part of the memory can safely be overwritten as it may be needed to
     prevent object recycling.

     That has the consequence that SLAB_TYPESAFE_BY_RCU may end up
     adding a new cacheline.

     So this also contains work to add a new kmem_cache_create_rcu()
     function that allows the caller to specify an offset where the
     freelist pointer is supposed to be placed. Thus avoiding the
     implicit addition of a fourth cacheline.

   - And finally this removes the f_version member in struct file.

     The f_version member isn't particularly well-defined. It is mainly
     used as a cookie to detect concurrent seeks when iterating
     directories. But it is also abused by some subsystems for
     completely unrelated things.

     It is mostly a directory and filesystem specific thing that doesn't
     really need to live in struct file and with its wonky semantics it
     really lacks a specific function.

     For pipes, f_version is (ab)used to defer poll notifications until
     a write has happened. And struct pipe_inode_info is used by
     multiple struct files in their ->private_data so there's no chance
     of pushing that down into file->private_data without introducing
     another pointer indirection.

     But pipes don't rely on f_pos_lock so this adds a union into struct
     file encompassing f_pos_lock and a pipe specific f_pipe member that
     pipes can use. This union of course can be extended to other file
     types and is similar to what we do in struct inode already"

* tag 'vfs-6.12.file' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (26 commits)
  fs: remove f_version
  pipe: use f_pipe
  fs: add f_pipe
  ubifs: store cookie in private data
  ufs: store cookie in private data
  udf: store cookie in private data
  proc: store cookie in private data
  ocfs2: store cookie in private data
  input: remove f_version abuse
  ext4: store cookie in private data
  ext2: store cookie in private data
  affs: store cookie in private data
  fs: add generic_llseek_cookie()
  fs: use must_set_pos()
  fs: add must_set_pos()
  fs: add vfs_setpos_cookie()
  s390: remove unused f_version
  ceph: remove unused f_version
  adi: remove unused f_version
  mm: Removed @freeptr_offset to prevent doc warning
  ...
2024-09-16 09:14:02 +02:00
Linus Torvalds
8f72c31f45 vfs-6.12.misc
-----BEGIN PGP SIGNATURE-----
 
 iHUEABYKAB0WIQRAhzRXHqcMeLMyaSiRxhvAZXjcogUCZuQEGwAKCRCRxhvAZXjc
 ojIuAQC433+hBkvjvmQ7H0r5rgZSjUuCTG3bSmdU7RJmPHUHhwEA85v/NGq53f+W
 IhandK6t+Cf0JYpFZ3N0bT88hDYVhQQ=
 =9zGL
 -----END PGP SIGNATURE-----

Merge tag 'vfs-6.12.misc' of gitolite.kernel.org:pub/scm/linux/kernel/git/vfs/vfs

Pull misc vfs updates from Christian Brauner:
 "This contains the usual pile of misc updates:

  Features:

   - Add F_CREATED_QUERY fcntl() that allows userspace to query whether
     a file was actually created. Often userspace wants to know whether
     an O_CREATE request did actually create a file without using
     O_EXCL. The current logic is that to first attempts to open the
     file without O_CREAT | O_EXCL and if ENOENT is returned userspace
     tries again with both flags. If that succeeds all is well. If it
     now reports EEXIST it retries.

     That works fairly well but some corner cases make this more
     involved. If this operates on a dangling symlink the first openat()
     without O_CREAT | O_EXCL will return ENOENT but the second openat()
     with O_CREAT | O_EXCL will fail with EEXIST.

     The reason is that openat() without O_CREAT | O_EXCL follows the
     symlink while O_CREAT | O_EXCL doesn't for security reasons. So
     it's not something we can really change unless we add an explicit
     opt-in via O_FOLLOW which seems really ugly.

     All available workarounds are really nasty (fanotify, bpf lsm etc)
     so add a simple fcntl().

   - Try an opportunistic lookup for O_CREAT. Today, when opening a file
     we'll typically do a fast lookup, but if O_CREAT is set, the kernel
     always takes the exclusive inode lock. This was likely done with
     the expectation that O_CREAT means that we always expect to do the
     create, but that's often not the case. Many programs set O_CREAT
     even in scenarios where the file already exists (see related
     F_CREATED_QUERY patch motivation above).

     The series contained in the pr rearranges the pathwalk-for-open
     code to also attempt a fast_lookup in certain O_CREAT cases. If a
     positive dentry is found, the inode_lock can be avoided altogether
     and it can stay in rcuwalk mode for the last step_into.

   - Expose the 64 bit mount id via name_to_handle_at()

     Now that we provide a unique 64-bit mount ID interface in statx(2),
     we can now provide a race-free way for name_to_handle_at(2) to
     provide a file handle and corresponding mount without needing to
     worry about racing with /proc/mountinfo parsing or having to open a
     file just to do statx(2).

     While this is not necessary if you are using AT_EMPTY_PATH and
     don't care about an extra statx(2) call, users that pass full paths
     into name_to_handle_at(2) need to know which mount the file handle
     comes from (to make sure they don't try to open_by_handle_at a file
     handle from a different filesystem) and switching to AT_EMPTY_PATH
     would require allocating a file for every name_to_handle_at(2) call

   - Add a per dentry expire timeout to autofs

     There are two fairly well known automounter map formats, the autofs
     format and the amd format (more or less System V and Berkley).

     Some time ago Linux autofs added an amd map format parser that
     implemented a fair amount of the amd functionality. This was done
     within the autofs infrastructure and some functionality wasn't
     implemented because it either didn't make sense or required extra
     kernel changes. The idea was to restrict changes to be within the
     existing autofs functionality as much as possible and leave changes
     with a wider scope to be considered later.

     One of these changes is implementing the amd options:
      1) "unmount", expire this mount according to a timeout (same as
         the current autofs default).
      2) "nounmount", don't expire this mount (same as setting the
         autofs timeout to 0 except only for this specific mount) .
      3) "utimeout=<seconds>", expire this mount using the specified
         timeout (again same as setting the autofs timeout but only for
         this mount)

     To implement these options per-dentry expire timeouts need to be
     implemented for autofs indirect mounts. This is because all map
     keys (mounts) for autofs indirect mounts use an expire timeout
     stored in the autofs mount super block info. structure and all
     indirect mounts use the same expire timeout.

  Fixes:

   - Fix missing fput for FSCONFIG_SET_FD in autofs

   - Use param->file for FSCONFIG_SET_FD in coda

   - Delete the 'fs/netfs' proc subtreee when netfs module exits

   - Make sure that struct uid_gid_map fits into a single cacheline

   - Don't flush in-flight wb switches for superblocks without cgroup
     writeback

   - Correcting the idmapping mount example in the idmapping
     documentation

   - Fix a race between evice_inodes() and find_inode() and iput()

   - Refine the show_inode_state() macro definition in writeback code

   - Prevent dump_mapping() from accessing invalid dentry.d_name.name

   - Show actual source for debugfs in /proc/mounts

   - Annotate data-race of busy_poll_usecs in eventpoll

   - Don't WARN for racy path_noexec check in exec code

   - Handle OOM on mnt_warn_timestamp_expiry()

   - Fix some spelling in the iomap design documentation

   - Fix typo in procfs comment

   - Fix typo in fs/namespace.c comment

  Cleanups:

   - Add the VFS git tree to the MAINTAINERS file

   - Move FMODE_UNSIGNED_OFFSET to fop_flags freeing up another f_mode
     bit in struct file bringing us to 5 free f_mode bits

   - Remove the __I_DIO_WAKEUP bit from i_state flags as we can simplify
     the wait mechanism

   - Remove the unused path_put_init() helper

   - Replace a __u32 with u32 for s_fsnotify_mask as __u32 is uapi
     specific

   - Replace the unsigned long i_state member with a u32 i_state member
     in struct inode freeing up 4 bytes in struct inode. Instead of
     using the bit based wait apis we're now using the var event apis
     and using the individual bytes of the i_state member to wait on
     state changes

   - Explain how per-syscall AT_* flags should be allocated

   - Use in_group_or_capable() helper to simplify the posix acl mode
     update code

   - Switch to LIST_HEAD() in fsync_buffers_list() to simplify the code

   - Removed comment about d_rcu_to_refcount() as that function doesn't
     exist anymore

   - Add kernel documentation for lookup_fast()

   - Don't re-zero evenpoll fields

   - Remove outdated comment after close_fd()

   - Fix imprecise wording in comment about the pipe filesystem

   - Drop GFP_NOFAIL mode from alloc_page_buffers

   - Missing blank line warnings and struct declaration improved in
     file_table

   - Annotate struct poll_list with __counted_by()

   - Remove the unused read parameter in percpu-rwsem

   - Remove linux/prefetch.h include from direct-io code

   - Use kmemdup_array instead of kmemdup for multiple allocation in
     mnt_idmapping code

   - Remove unused mnt_cursor_del() declaration

  Performance tweaks:

   - Dodge smp_mb in break_lease and break_deleg in the common case

   - Only read fops once in fops_{get,put}()

   - Use RCU in ilookup()

   - Elide smp_mb in iversion handling in the common case

   - Drop one lock trip in evict()"

* tag 'vfs-6.12.misc' of gitolite.kernel.org:pub/scm/linux/kernel/git/vfs/vfs: (58 commits)
  uidgid: make sure we fit into one cacheline
  proc: Fix typo in the comment
  fs/pipe: Correct imprecise wording in comment
  fhandle: expose u64 mount id to name_to_handle_at(2)
  uapi: explain how per-syscall AT_* flags should be allocated
  fs: drop GFP_NOFAIL mode from alloc_page_buffers
  writeback: Refine the show_inode_state() macro definition
  fs/inode: Prevent dump_mapping() accessing invalid dentry.d_name.name
  mnt_idmapping: Use kmemdup_array instead of kmemdup for multiple allocation
  netfs: Delete subtree of 'fs/netfs' when netfs module exits
  fs: use LIST_HEAD() to simplify code
  inode: make i_state a u32
  inode: port __I_LRU_ISOLATING to var event
  vfs: fix race between evice_inodes() and find_inode()&iput()
  inode: port __I_NEW to var event
  inode: port __I_SYNC to var event
  fs: reorder i_state bits
  fs: add i_state helpers
  MAINTAINERS: add the VFS git tree
  fs: s/__u32/u32/ for s_fsnotify_mask
  ...
2024-09-16 08:35:09 +02:00
Christophe Leroy
d175ee98fe mm: Define VM_DROPPABLE for powerpc/32
Commit 9651fcedf7 ("mm: add MAP_DROPPABLE for designating always
lazily freeable mappings") only adds VM_DROPPABLE for 64 bits
architectures.

In order to also use the getrandom vDSO implementation on powerpc/32,
use VM_ARCH_1 for VM_DROPPABLE on powerpc/32. This is possible because
VM_ARCH_1 is used for VM_SAO on powerpc and VM_SAO is only for
powerpc/64. It is used in combination with PROT_SAO in some parts of
code that are restricted to CONFIG_PPC64 through #ifdefs, it is
therefore possible to define VM_SAO for CONFIG_PPC64 only.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2024-09-13 17:28:36 +02:00
Christian Brauner
b4dba2efa8
proc: store cookie in private data
Store the cookie to detect concurrent seeks on directories in
file->private_data.

Link: https://lore.kernel.org/r/20240830-vfs-file-f_version-v1-14-6d3e4816aa7b@kernel.org
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-09-12 11:58:44 +02:00
Alexey Dobriyan
4ad5f9a021
proc: fold kmalloc() + strcpy() into kmemdup()
strcpy() will recalculate string length second time which is
unnecessary in this case.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Link: https://lore.kernel.org/r/90af27c1-0b86-47a6-a6c8-61a58b8aa747@p183
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-09-09 10:51:20 +02:00
Yan Zhen
698e7d1680
proc: Fix typo in the comment
The deference here confuses me.

Maybe here want to say that because show_fd_locks() does not dereference
the files pointer, using the stale value of the files pointer is safe.

Correctly spelled comments make it easier for the reader to understand
the code.

replace 'deferences' with 'dereferences' in the comment &
replace 'inialized' with 'initialized' in the comment.

Signed-off-by: Yan Zhen <yanzhen@vivo.com>
Link: https://lore.kernel.org/r/20240909063353.2246419-1-yanzhen@vivo.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-09-09 09:51:16 +02:00
John Ogness
c83a20662d proc: Add nbcon support for /proc/consoles
Update /proc/consoles output to show 'W' if an nbcon console is
registered. Since the write_thread() callback is mandatory, it
enough just to check if it is an nbcon console.

Also update /proc/consoles output to show 'N' if it is an
nbcon console.

Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20240904120536.115780-14-john.ogness@linutronix.de
Signed-off-by: Petr Mladek <pmladek@suse.com>
2024-09-04 15:56:33 +02:00
John Ogness
fe6fa88d86 proc: consoles: Add notation to c_start/c_stop
fs/proc/consoles.c:78:13: warning: context imbalance in 'c_start'
	- wrong count at exit
fs/proc/consoles.c:104:13: warning: context imbalance in 'c_stop'
	- unexpected unlock

Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20240904120536.115780-13-john.ogness@linutronix.de
Signed-off-by: Petr Mladek <pmladek@suse.com>
2024-09-04 15:56:32 +02:00
Joey Gouly
9f82f15ddf mm: use ARCH_PKEY_BITS to define VM_PKEY_BITN
Use the new CONFIG_ARCH_PKEY_BITS to simplify setting these bits
for different architectures.

Signed-off-by: Joey Gouly <joey.gouly@arm.com>

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-fsdevel@vger.kernel.org
Cc: linux-mm@kvack.org
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Link: https://lore.kernel.org/r/20240822151113.1479789-4-joey.gouly@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
2024-09-04 12:52:40 +01:00
Matthew Wilcox (Oracle)
7a87225ae2 x86: remove PG_uncached
Convert x86 to use PG_arch_2 instead of PG_uncached and remove
PG_uncached.

Link: https://lkml.kernel.org/r/20240821193445.2294269-11-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-03 21:15:46 -07:00
Matthew Wilcox (Oracle)
02e1960aaf mm: rename PG_mappedtodisk to PG_owner_2
This flag has similar constraints to PG_owner_priv_1 -- it is ignored by
core code, and is entirely for the use of the code which allocated the
folio.  Since the pagecache does not use it, individual filesystems can
use it.  The bufferhead code does use it, so filesystems which use the
buffer cache must not use it for another purpose.

Link: https://lkml.kernel.org/r/20240821193445.2294269-10-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-03 21:15:45 -07:00
Matthew Wilcox (Oracle)
e880034cf7 mm: introduce page_mapcount_is_type()
Resolve the awkward "and add one to this opaque constant" test into a
self-documenting inline function.

Link: https://lkml.kernel.org/r/20240821173914.2270383-3-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-03 21:15:42 -07:00
Thomas Weißschuh
559d4c6a9d sysctl: avoid spurious permanent empty tables
The test if a table is a permanently empty one, inspects the address of
the registered ctl_table argument.
However as sysctl_mount_point is an empty array and does not occupy and
space it can end up sharing an address with another object in memory.
If that other object itself is a "struct ctl_table" then registering
that table will fail as it's incorrectly recognized as permanently empty.

Avoid this issue by adding a dummy element to the array so that is not
empty anymore.
Explicitly register the table with zero elements as otherwise the dummy
element would be recognized as a sentinel element which would lead to a
runtime warning from the sysctl core.

While the issue seems not being encountered at this time, this seems
mostly to be due to luck.
Also a future change, constifying sysctl_mount_point and root_table, can
reliably trigger this issue on clang 18.

Given that empty arrays are non-standard in the first place it seems
prudent to avoid them if possible.

Fixes: 4a7b29f650 ("sysctl: move sysctl type to ctl_table_header")
Fixes: a35dd3a786 ("sysctl: drop now unnecessary out-of-bounds check")
Cc: stable@vger.kernel.org
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Closes: https://lore.kernel.org/oe-lkp/202408051453.f638857e-lkp@intel.com
Signed-off-by: Joel Granados <j.granados@samsung.com>
2024-09-02 10:37:37 +02:00
Andrii Nakryiko
00bd8ec2f7 fs/procfs: remove build ID-related code duplication in PROCMAP_QUERY
A piece of build ID handling code in PROCMAP_QUERY ioctl() was
accidentally duplicated.  It wasn't meant to be part of ed5d583a88
("fs/procfs: implement efficient VMA querying API for /proc/<pid>/maps")
commit, which is what introduced duplication.

It has no correctness implications, but we unnecessarily perform the same
work twice, if build ID parsing is requested.  Drop the duplication.

Link: https://lkml.kernel.org/r/20240729174044.4008399-1-andrii@kernel.org
Fixes: ed5d583a88 ("fs/procfs: implement efficient VMA querying API for /proc/<pid>/maps")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Reported-by: Jann Horn <jannh@google.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-01 20:43:30 -07:00
Matthew Wilcox (Oracle)
09022bc196 mm: remove PG_error
The PG_error bit is now unused; delete it and free up a bit in
page->flags.

Link: https://lkml.kernel.org/r/20240807193528.1865100-2-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-01 20:26:05 -07:00
Christian Brauner
641bb4394f fs: move FMODE_UNSIGNED_OFFSET to fop_flags
This is another flag that is statically set and doesn't need to use up
an FMODE_* bit. Move it to ->fop_flags and free up another FMODE_* bit.

(1) mem_open() used from proc_mem_operations
(2) adi_open() used from adi_fops
(3) drm_open_helper():
    (3.1) accel_open() used from DRM_ACCEL_FOPS
    (3.2) drm_open() used from
    (3.2.1) amdgpu_driver_kms_fops
    (3.2.2) psb_gem_fops
    (3.2.3) i915_driver_fops
    (3.2.4) nouveau_driver_fops
    (3.2.5) panthor_drm_driver_fops
    (3.2.6) radeon_driver_kms_fops
    (3.2.7) tegra_drm_fops
    (3.2.8) vmwgfx_driver_fops
    (3.2.9) xe_driver_fops
    (3.2.10) DRM_GEM_FOPS
    (3.2.11) DEFINE_DRM_GEM_DMA_FOPS
(4) struct memdev sets fmode flags based on type of device opened. For
    devices using struct mem_fops unsigned offset is used.

Mark all these file operations as FOP_UNSIGNED_OFFSET and add asserts
into the open helper to ensure that the flag is always set.

Link: https://lore.kernel.org/r/20240809-work-fop_unsigned-v1-1-658e054d893e@kernel.org
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-08-30 08:22:36 +02:00
Christian Brauner
d80b065bb1
Merge patch series "proc: restrict overmounting of ephemeral entities"
Christian Brauner <brauner@kernel.org> says:

It is currently possible to mount on top of various ephemeral entities
in procfs. This specifically includes magic links. To recap, magic links
are links of the form /proc/<pid>/fd/<nr>. They serve as references to
a target file and during path lookup they cause a jump to the target
path. Such magic links disappear if the corresponding file descriptor is
closed.

Currently it is possible to overmount such magic links:

int fd = open("/mnt/foo", O_RDONLY);
sprintf(path, "/proc/%d/fd/%d", getpid(), fd);
int fd2 = openat(AT_FDCWD, path, O_PATH | O_NOFOLLOW);
mount("/mnt/bar", path, "", MS_BIND, 0);

Arguably, this is nonsensical and is mostly interesting for an attacker
that wants to somehow trick a process into e.g., reopening something
that they didn't intend to reopen or to hide a malicious file
descriptor.

But also it risks leaking mounts for long-running processes. When
overmounting a magic link like above, the mount will not be detached
when the file descriptor is closed. Only the target mountpoint will
disappear. Which has the consequence of making it impossible to unmount
that mount afterwards. So the mount will stick around until the process
exits and the /proc/<pid>/ directory is cleaned up during
proc_flush_pid() when the dentries are pruned and invalidated.

That in turn means it's possible for a program to accidentally leak
mounts and it's also possible to make a task leak mounts without it's
knowledge if the attacker just keeps overmounting things under
/proc/<pid>/fd/<nr>.

I think it's wrong to try and fix this by us starting to play games with
close() or somewhere else to undo these mounts when the file descriptor
is closed. The fact that we allow overmounting of such magic links is
simply a bug and one that we need to fix.

Similar things can be said about entries under fdinfo/ and map_files/ so
those are restricted as well.

I have a further more aggressive patch that gets out the big hammer and
makes everything under /proc/<pid>/*, as well as immediate symlinks such
as /proc/self, /proc/thread-self, /proc/mounts, /proc/net that point
into /proc/<pid>/ not overmountable. Imho, all of this should be blocked
if we can get away with it. It's only useful to hide exploits such as in [1].

And again, overmounting of any global procfs files remains unaffected
and is an existing and supported use-case.

Link: https://righteousit.com/2024/07/24/hiding-linux-processes-with-bind-mounts [1]

// Note that repro uses the traditional way of just mounting over
// /proc/<pid>/fd/<nr>. This could also all be achieved just based on
// file descriptors using move_mount(). So /proc/<pid>/fd/<nr> isn't the
// only entry vector here. It's also possible to e.g., mount directly
// onto /proc/<pid>/map_files/* without going over /proc/<pid>/fd/<nr>.
int main(int argc, char *argv[])
{
        char path[PATH_MAX];

        creat("/mnt/foo", 0777);
        creat("/mnt/bar", 0777);

        /*
         * For illustration use a bunch of file descriptors in the upper
         * range that are unused.
         */
        for (int i = 10000; i >= 256; i--) {
                printf("I'm: /proc/%d/\n", getpid());

                int fd2 = open("/mnt/foo", O_RDONLY);
                if (fd2 < 0) {
                        printf("%m - Failed to open\n");
                        _exit(1);
                }

                int newfd = dup2(fd2, i);
                if (newfd < 0) {
                        printf("%m - Failed to dup\n");
                        _exit(1);
                }
                close(fd2);

                sprintf(path, "/proc/%d/fd/%d", getpid(), newfd);
                int fd = openat(AT_FDCWD, path, O_PATH | O_NOFOLLOW);
                if (fd < 0) {
                        printf("%m - Failed to open\n");
                        _exit(3);
                }

                sprintf(path, "/proc/%d/fd/%d", getpid(), fd);
                printf("Mounting on top of %s\n", path);
                if (mount("/mnt/bar", path, "", MS_BIND, 0)) {
                        printf("%m - Failed to mount\n");
                        _exit(4);
                }

                close(newfd);
                close(fd2);
        }

        /*
         * Give some time to look at things. The mounts now linger until
         * the process exits.
         */
        sleep(10000);
        _exit(0);
}

* patches from https://lore.kernel.org/r/20240806-work-procfs-v1-0-fb04e1d09f0c@kernel.org:
  proc: block mounting on top of /proc/<pid>/fdinfo/*
  proc: block mounting on top of /proc/<pid>/fd/*
  proc: block mounting on top of /proc/<pid>/map_files/*
  proc: add proc_splice_unmountable()
  proc: proc_readfdinfo() -> proc_fdinfo_iterate()
  proc: proc_readfd() -> proc_fd_iterate()

Link: https://lore.kernel.org/r/20240806-work-procfs-v1-0-fb04e1d09f0c@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-08-30 08:22:13 +02:00
Christian Brauner
cf71eaa1ad
proc: block mounting on top of /proc/<pid>/fdinfo/*
Entries under /proc/<pid>/fdinfo/* are ephemeral and may go away before
the process dies. As such allowing them to be used as mount points
creates the ability to leak mounts that linger until the process dies
with no ability to unmount them until then. Don't allow using them as
mountpoints.

Link: https://lore.kernel.org/r/20240806-work-procfs-v1-6-fb04e1d09f0c@kernel.org
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-08-30 08:22:13 +02:00
Christian Brauner
74ce208089
proc: block mounting on top of /proc/<pid>/fd/*
Entries under /proc/<pid>/fd/* are ephemeral and may go away before the
process dies. As such allowing them to be used as mount points creates
the ability to leak mounts that linger until the process dies with no
ability to unmount them until then. Don't allow using them as
mountpoints.

Link: https://lore.kernel.org/r/20240806-work-procfs-v1-5-fb04e1d09f0c@kernel.org
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-08-30 08:22:13 +02:00
Christian Brauner
3836b31c3e
proc: block mounting on top of /proc/<pid>/map_files/*
Entries under /proc/<pid>/map_files/* are ephemeral and may go away
before the process dies. As such allowing them to be used as mount
points creates the ability to leak mounts that linger until the process
dies with no ability to unmount them until then. Don't allow using them
as mountpoints.

Link: https://lore.kernel.org/r/20240806-work-procfs-v1-4-fb04e1d09f0c@kernel.org
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-08-30 08:22:12 +02:00
Christian Brauner
32a0a965b8
proc: add proc_splice_unmountable()
Add a tiny procfs helper to splice a dentry that cannot be mounted upon.

Link: https://lore.kernel.org/r/20240806-work-procfs-v1-3-fb04e1d09f0c@kernel.org
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-08-30 08:22:12 +02:00
Christian Brauner
55d4860db2
proc: proc_readfdinfo() -> proc_fdinfo_iterate()
Give the method to iterate through the fdinfo directory a better name.

Link: https://lore.kernel.org/r/20240806-work-procfs-v1-2-fb04e1d09f0c@kernel.org
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-08-30 08:22:05 +02:00
Christian Brauner
b69181b871
proc: proc_readfd() -> proc_fd_iterate()
Give the method to iterate through the fd directory a better name.

Link: https://lore.kernel.org/r/20240806-work-procfs-v1-1-fb04e1d09f0c@kernel.org
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-08-30 08:21:34 +02:00
Adrian Ratiu
41e8149c88
proc: add config & param to block forcing mem writes
This adds a Kconfig option and boot param to allow removing
the FOLL_FORCE flag from /proc/pid/mem write calls because
it can be abused.

The traditional forcing behavior is kept as default because
it can break GDB and some other use cases.

Previously we tried a more sophisticated approach allowing
distributions to fine-tune /proc/pid/mem behavior, however
that got NAK-ed by Linus [1], who prefers this simpler
approach with semantics also easier to understand for users.

Link: https://lore.kernel.org/lkml/CAHk-=wiGWLChxYmUA5HrT5aopZrB7_2VTa0NLZcxORgkUe5tEQ@mail.gmail.com/ [1]
Cc: Doug Anderson <dianders@chromium.org>
Cc: Jeff Xu <jeffxu@google.com>
Cc: Jann Horn <jannh@google.com>
Cc: Kees Cook <kees@kernel.org>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Christian Brauner <brauner@kernel.org>
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Adrian Ratiu <adrian.ratiu@collabora.com>
Link: https://lore.kernel.org/r/20240802080225.89408-1-adrian.ratiu@collabora.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-08-30 08:19:43 +02:00
Felix Moessbauer
ed4fb6d7ef hrtimer: Use and report correct timerslack values for realtime tasks
The timerslack_ns setting is used to specify how much the hardware
timers should be delayed, to potentially dispatch multiple timers in a
single interrupt. This is a performance optimization. Timers of
realtime tasks (having a realtime scheduling policy) should not be
delayed.

This logic was inconsitently applied to the hrtimers, leading to delays
of realtime tasks which used timed waits for events (e.g. condition
variables). Due to the downstream override of the slack for rt tasks,
the procfs reported incorrect (non-zero) timerslack_ns values.

This is changed by setting the timer_slack_ns task attribute to 0 for
all tasks with a rt policy. By that, downstream users do not need to
specially handle rt tasks (w.r.t. the slack), and the procfs entry
shows the correct value of "0". Setting non-zero slack values (either
via procfs or PR_SET_TIMERSLACK) on tasks with a rt policy is ignored,
as stated in "man 2 PR_SET_TIMERSLACK":

  Timer slack is not applied to threads that are scheduled under a
  real-time scheduling policy (see sched_setscheduler(2)).

The special handling of timerslack on rt tasks in downstream users
is removed as well.

Signed-off-by: Felix Moessbauer <felix.moessbauer@siemens.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20240814121032.368444-2-felix.moessbauer@siemens.com
2024-08-23 20:13:02 +02:00
Thomas Gleixner
52dea0a15c posix-timers: Convert timer list to hlist
No requirement for a real list. Spare a few bytes.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
2024-07-29 21:57:35 +02:00
Linus Torvalds
7a3fad30fd Random number generator updates for Linux 6.11-rc1.
-----BEGIN PGP SIGNATURE-----
 
 iQIzBAABCAAdFiEEq5lC5tSkz8NBJiCnSfxwEqXeA64FAmaarzgACgkQSfxwEqXe
 A66ZWBAAlhXx8bve0uKlDRK8fffWHgruho/fOY4lZJ137AKwA9JCtmOyqdfL4Dmk
 VxFe7pEQJlQhcA/6kH54uO7SBXwfKlKZJth6SYnaCRMUIbFifHjjIQ0QqldjEKi0
 rP90Hu4FVsbwQC7u9i9lQj9n2P36zb6pn83BzpZQ/2PtoVCSCrdSJUe0Rxa3H3GN
 0+nNkDSXQt5otCByLaeE3x7KJgXLWL9+G2eFSFLTZ8rSVfMx1CdOIAG37WlLGdWm
 BaFYPDKMyBTVvVJBNgAe9YSqtrsZ5nlmLz+Z9wAe/hTL7RlL03kWUu34/Udcpull
 zzMDH0WMntiGK3eFQ2gOYSWqypvAjwHgn3BzqNmjUb69+89mZsdU1slcvnxWsUwU
 D3vphrscaqarF629tfsXti3jc5PoXwUTjROZVcCyeFPBhyAZgzK8xUvPpJO+RT+K
 EuUABob9cpA6FCpW/QeolDmMDhXlNT8QgsZu1juokZac2xP3Ly3REyEvT7HLbU2W
 ZJjbEqm1ppp3RmGELUOJbyhwsLrnbt+OMDO7iEWoG8aSFK4diBK/ZM6WvLMkr8Oi
 7ioXGIsYkCy3c47wpZKTrAapOPJp5keqNAiHSEbXw8mozp6429QAEZxNOcczgHKC
 Ea2JzRkctqutcIT+Slw/uUe//i1iSsIHXbE81fp5udcQTJcUByo=
 =P8aI
 -----END PGP SIGNATURE-----

Merge tag 'random-6.11-rc1-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/crng/random

Pull random number generator updates from Jason Donenfeld:
 "This adds getrandom() support to the vDSO.

  First, it adds a new kind of mapping to mmap(2), MAP_DROPPABLE, which
  lets the kernel zero out pages anytime under memory pressure, which
  enables allocating memory that never gets swapped to disk but also
  doesn't count as being mlocked.

  Then, the vDSO implementation of getrandom() is introduced in a
  generic manner and hooked into random.c.

  Next, this is implemented on x86. (Also, though it's not ready for
  this pull, somebody has begun an arm64 implementation already)

  Finally, two vDSO selftests are added.

  There are also two housekeeping cleanup commits"

* tag 'random-6.11-rc1-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/crng/random:
  MAINTAINERS: add random.h headers to RNG subsection
  random: note that RNDGETPOOL was removed in 2.6.9-rc2
  selftests/vDSO: add tests for vgetrandom
  x86: vdso: Wire up getrandom() vDSO implementation
  random: introduce generic vDSO getrandom() implementation
  mm: add MAP_DROPPABLE for designating always lazily freeable mappings
2024-07-24 10:29:50 -07:00
Linus Torvalds
fbc90c042c - 875fa64577da ("mm/hugetlb_vmemmap: fix race with speculative PFN
walkers") is known to cause a performance regression
   (https://lore.kernel.org/all/3acefad9-96e5-4681-8014-827d6be71c7a@linux.ibm.com/T/#mfa809800a7862fb5bdf834c6f71a3a5113eb83ff).
   Yu has a fix which I'll send along later via the hotfixes branch.
 
 - In the series "mm: Avoid possible overflows in dirty throttling" Jan
   Kara addresses a couple of issues in the writeback throttling code.
   These fixes are also targetted at -stable kernels.
 
 - Ryusuke Konishi's series "nilfs2: fix potential issues related to
   reserved inodes" does that.  This should actually be in the
   mm-nonmm-stable tree, along with the many other nilfs2 patches.  My bad.
 
 - More folio conversions from Kefeng Wang in the series "mm: convert to
   folio_alloc_mpol()"
 
 - Kemeng Shi has sent some cleanups to the writeback code in the series
   "Add helper functions to remove repeated code and improve readability of
   cgroup writeback"
 
 - Kairui Song has made the swap code a little smaller and a little
   faster in the series "mm/swap: clean up and optimize swap cache index".
 
 - In the series "mm/memory: cleanly support zeropage in
   vm_insert_page*(), vm_map_pages*() and vmf_insert_mixed()" David
   Hildenbrand has reworked the rather sketchy handling of the use of the
   zeropage in MAP_SHARED mappings.  I don't see any runtime effects here -
   more a cleanup/understandability/maintainablity thing.
 
 - Dev Jain has improved selftests/mm/va_high_addr_switch.c's handling of
   higher addresses, for aarch64.  The (poorly named) series is
   "Restructure va_high_addr_switch".
 
 - The core TLB handling code gets some cleanups and possible slight
   optimizations in Bang Li's series "Add update_mmu_tlb_range() to
   simplify code".
 
 - Jane Chu has improved the handling of our
   fake-an-unrecoverable-memory-error testing feature MADV_HWPOISON in the
   series "Enhance soft hwpoison handling and injection".
 
 - Jeff Johnson has sent a billion patches everywhere to add
   MODULE_DESCRIPTION() to everything.  Some landed in this pull.
 
 - In the series "mm: cleanup MIGRATE_SYNC_NO_COPY mode", Kefeng Wang has
   simplified migration's use of hardware-offload memory copying.
 
 - Yosry Ahmed performs more folio API conversions in his series "mm:
   zswap: trivial folio conversions".
 
 - In the series "large folios swap-in: handle refault cases first",
   Chuanhua Han inches us forward in the handling of large pages in the
   swap code.  This is a cleanup and optimization, working toward the end
   objective of full support of large folio swapin/out.
 
 - In the series "mm,swap: cleanup VMA based swap readahead window
   calculation", Huang Ying has contributed some cleanups and a possible
   fixlet to his VMA based swap readahead code.
 
 - In the series "add mTHP support for anonymous shmem" Baolin Wang has
   taught anonymous shmem mappings to use multisize THP.  By default this
   is a no-op - users must opt in vis sysfs controls.  Dramatic
   improvements in pagefault latency are realized.
 
 - David Hildenbrand has some cleanups to our remaining use of
   page_mapcount() in the series "fs/proc: move page_mapcount() to
   fs/proc/internal.h".
 
 - David also has some highmem accounting cleanups in the series
   "mm/highmem: don't track highmem pages manually".
 
 - Build-time fixes and cleanups from John Hubbard in the series
   "cleanups, fixes, and progress towards avoiding "make headers"".
 
 - Cleanups and consolidation of the core pagemap handling from Barry
   Song in the series "mm: introduce pmd|pte_needs_soft_dirty_wp helpers
   and utilize them".
 
 - Lance Yang's series "Reclaim lazyfree THP without splitting" has
   reduced the latency of the reclaim of pmd-mapped THPs under fairly
   common circumstances.  A 10x speedup is seen in a microbenchmark.
 
   It does this by punting to aother CPU but I guess that's a win unless
   all CPUs are pegged.
 
 - hugetlb_cgroup cleanups from Xiu Jianfeng in the series
   "mm/hugetlb_cgroup: rework on cftypes".
 
 - Miaohe Lin's series "Some cleanups for memory-failure" does just that
   thing.
 
 - Is anyone reading this stuff?  If so, email me!
 
 - Someone other than SeongJae has developed a DAMON feature in Honggyu
   Kim's series "DAMON based tiered memory management for CXL memory".
   This adds DAMON features which may be used to help determine the
   efficiency of our placement of CXL/PCIe attached DRAM.
 
 - DAMON user API centralization and simplificatio work in SeongJae
   Park's series "mm/damon: introduce DAMON parameters online commit
   function".
 
 - In the series "mm: page_type, zsmalloc and page_mapcount_reset()"
   David Hildenbrand does some maintenance work on zsmalloc - partially
   modernizing its use of pageframe fields.
 
 - Kefeng Wang provides more folio conversions in the series "mm: remove
   page_maybe_dma_pinned() and page_mkclean()".
 
 - More cleanup from David Hildenbrand, this time in the series
   "mm/memory_hotplug: use PageOffline() instead of PageReserved() for
   !ZONE_DEVICE".  It "enlightens memory hotplug more about PageOffline()
   pages" and permits the removal of some virtio-mem hacks.
 
 - Barry Song's series "mm: clarify folio_add_new_anon_rmap() and
   __folio_add_anon_rmap()" is a cleanup to the anon folio handling in
   preparation for mTHP (multisize THP) swapin.
 
 - Kefeng Wang's series "mm: improve clear and copy user folio"
   implements more folio conversions, this time in the area of large folio
   userspace copying.
 
 - The series "Docs/mm/damon/maintaier-profile: document a mailing tool
   and community meetup series" tells people how to get better involved
   with other DAMON developers.  From SeongJae Park.
 
 - A large series ("kmsan: Enable on s390") from Ilya Leoshkevich does
   that.
 
 - David Hildenbrand sends along more cleanups, this time against the
   migration code.  The series is "mm/migrate: move NUMA hinting fault
   folio isolation + checks under PTL".
 
 - Jan Kara has found quite a lot of strangenesses and minor errors in
   the readahead code.  He addresses this in the series "mm: Fix various
   readahead quirks".
 
 - SeongJae Park's series "selftests/damon: test DAMOS tried regions and
   {min,max}_nr_regions" adds features and addresses errors in DAMON's self
   testing code.
 
 - Gavin Shan has found a userspace-triggerable WARN in the pagecache
   code.  The series "mm/filemap: Limit page cache size to that supported
   by xarray" addresses this.  The series is marked cc:stable.
 
 - Chengming Zhou's series "mm/ksm: cmp_and_merge_page() optimizations
   and cleanup" cleans up and slightly optimizes KSM.
 
 - Roman Gushchin has separated the memcg-v1 and memcg-v2 code - lots of
   code motion.  The series (which also makes the memcg-v1 code
   Kconfigurable) are
 
   "mm: memcg: separate legacy cgroup v1 code and put under config
   option" and
   "mm: memcg: put cgroup v1-specific memcg data under CONFIG_MEMCG_V1"
 
 - Dan Schatzberg's series "Add swappiness argument to memory.reclaim"
   adds an additional feature to this cgroup-v2 control file.
 
 - The series "Userspace controls soft-offline pages" from Jiaqi Yan
   permits userspace to stop the kernel's automatic treatment of excessive
   correctable memory errors.  In order to permit userspace to monitor and
   handle this situation.
 
 - Kefeng Wang's series "mm: migrate: support poison recover from migrate
   folio" teaches the kernel to appropriately handle migration from
   poisoned source folios rather than simply panicing.
 
 - SeongJae Park's series "Docs/damon: minor fixups and improvements"
   does those things.
 
 - In the series "mm/zsmalloc: change back to per-size_class lock"
   Chengming Zhou improves zsmalloc's scalability and memory utilization.
 
 - Vivek Kasireddy's series "mm/gup: Introduce memfd_pin_folios() for
   pinning memfd folios" makes the GUP code use FOLL_PIN rather than bare
   refcount increments.  So these paes can first be moved aside if they
   reside in the movable zone or a CMA block.
 
 - Andrii Nakryiko has added a binary ioctl()-based API to /proc/pid/maps
   for much faster reading of vma information.  The series is "query VMAs
   from /proc/<pid>/maps".
 
 - In the series "mm: introduce per-order mTHP split counters" Lance Yang
   improves the kernel's presentation of developer information related to
   multisize THP splitting.
 
 - Michael Ellerman has developed the series "Reimplement huge pages
   without hugepd on powerpc (8xx, e500, book3s/64)".  This permits
   userspace to use all available huge page sizes.
 
 - In the series "revert unconditional slab and page allocator fault
   injection calls" Vlastimil Babka removes a performance-affecting and not
   very useful feature from slab fault injection.
 -----BEGIN PGP SIGNATURE-----
 
 iHUEABYKAB0WIQTTMBEPP41GrTpTJgfdBJ7gKXxAjgUCZp2C+QAKCRDdBJ7gKXxA
 joTkAQDvjqOoFStqk4GU3OXMYB7WCU/ZQMFG0iuu1EEwTVDZ4QEA8CnG7seek1R3
 xEoo+vw0sWWeLV3qzsxnCA1BJ8cTJA8=
 =z0Lf
 -----END PGP SIGNATURE-----

Merge tag 'mm-stable-2024-07-21-14-50' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull MM updates from Andrew Morton:

 - In the series "mm: Avoid possible overflows in dirty throttling" Jan
   Kara addresses a couple of issues in the writeback throttling code.
   These fixes are also targetted at -stable kernels.

 - Ryusuke Konishi's series "nilfs2: fix potential issues related to
   reserved inodes" does that. This should actually be in the
   mm-nonmm-stable tree, along with the many other nilfs2 patches. My
   bad.

 - More folio conversions from Kefeng Wang in the series "mm: convert to
   folio_alloc_mpol()"

 - Kemeng Shi has sent some cleanups to the writeback code in the series
   "Add helper functions to remove repeated code and improve readability
   of cgroup writeback"

 - Kairui Song has made the swap code a little smaller and a little
   faster in the series "mm/swap: clean up and optimize swap cache
   index".

 - In the series "mm/memory: cleanly support zeropage in
   vm_insert_page*(), vm_map_pages*() and vmf_insert_mixed()" David
   Hildenbrand has reworked the rather sketchy handling of the use of
   the zeropage in MAP_SHARED mappings. I don't see any runtime effects
   here - more a cleanup/understandability/maintainablity thing.

 - Dev Jain has improved selftests/mm/va_high_addr_switch.c's handling
   of higher addresses, for aarch64. The (poorly named) series is
   "Restructure va_high_addr_switch".

 - The core TLB handling code gets some cleanups and possible slight
   optimizations in Bang Li's series "Add update_mmu_tlb_range() to
   simplify code".

 - Jane Chu has improved the handling of our
   fake-an-unrecoverable-memory-error testing feature MADV_HWPOISON in
   the series "Enhance soft hwpoison handling and injection".

 - Jeff Johnson has sent a billion patches everywhere to add
   MODULE_DESCRIPTION() to everything. Some landed in this pull.

 - In the series "mm: cleanup MIGRATE_SYNC_NO_COPY mode", Kefeng Wang
   has simplified migration's use of hardware-offload memory copying.

 - Yosry Ahmed performs more folio API conversions in his series "mm:
   zswap: trivial folio conversions".

 - In the series "large folios swap-in: handle refault cases first",
   Chuanhua Han inches us forward in the handling of large pages in the
   swap code. This is a cleanup and optimization, working toward the end
   objective of full support of large folio swapin/out.

 - In the series "mm,swap: cleanup VMA based swap readahead window
   calculation", Huang Ying has contributed some cleanups and a possible
   fixlet to his VMA based swap readahead code.

 - In the series "add mTHP support for anonymous shmem" Baolin Wang has
   taught anonymous shmem mappings to use multisize THP. By default this
   is a no-op - users must opt in vis sysfs controls. Dramatic
   improvements in pagefault latency are realized.

 - David Hildenbrand has some cleanups to our remaining use of
   page_mapcount() in the series "fs/proc: move page_mapcount() to
   fs/proc/internal.h".

 - David also has some highmem accounting cleanups in the series
   "mm/highmem: don't track highmem pages manually".

 - Build-time fixes and cleanups from John Hubbard in the series
   "cleanups, fixes, and progress towards avoiding "make headers"".

 - Cleanups and consolidation of the core pagemap handling from Barry
   Song in the series "mm: introduce pmd|pte_needs_soft_dirty_wp helpers
   and utilize them".

 - Lance Yang's series "Reclaim lazyfree THP without splitting" has
   reduced the latency of the reclaim of pmd-mapped THPs under fairly
   common circumstances. A 10x speedup is seen in a microbenchmark.

   It does this by punting to aother CPU but I guess that's a win unless
   all CPUs are pegged.

 - hugetlb_cgroup cleanups from Xiu Jianfeng in the series
   "mm/hugetlb_cgroup: rework on cftypes".

 - Miaohe Lin's series "Some cleanups for memory-failure" does just that
   thing.

 - Someone other than SeongJae has developed a DAMON feature in Honggyu
   Kim's series "DAMON based tiered memory management for CXL memory".
   This adds DAMON features which may be used to help determine the
   efficiency of our placement of CXL/PCIe attached DRAM.

 - DAMON user API centralization and simplificatio work in SeongJae
   Park's series "mm/damon: introduce DAMON parameters online commit
   function".

 - In the series "mm: page_type, zsmalloc and page_mapcount_reset()"
   David Hildenbrand does some maintenance work on zsmalloc - partially
   modernizing its use of pageframe fields.

 - Kefeng Wang provides more folio conversions in the series "mm: remove
   page_maybe_dma_pinned() and page_mkclean()".

 - More cleanup from David Hildenbrand, this time in the series
   "mm/memory_hotplug: use PageOffline() instead of PageReserved() for
   !ZONE_DEVICE". It "enlightens memory hotplug more about PageOffline()
   pages" and permits the removal of some virtio-mem hacks.

 - Barry Song's series "mm: clarify folio_add_new_anon_rmap() and
   __folio_add_anon_rmap()" is a cleanup to the anon folio handling in
   preparation for mTHP (multisize THP) swapin.

 - Kefeng Wang's series "mm: improve clear and copy user folio"
   implements more folio conversions, this time in the area of large
   folio userspace copying.

 - The series "Docs/mm/damon/maintaier-profile: document a mailing tool
   and community meetup series" tells people how to get better involved
   with other DAMON developers. From SeongJae Park.

 - A large series ("kmsan: Enable on s390") from Ilya Leoshkevich does
   that.

 - David Hildenbrand sends along more cleanups, this time against the
   migration code. The series is "mm/migrate: move NUMA hinting fault
   folio isolation + checks under PTL".

 - Jan Kara has found quite a lot of strangenesses and minor errors in
   the readahead code. He addresses this in the series "mm: Fix various
   readahead quirks".

 - SeongJae Park's series "selftests/damon: test DAMOS tried regions and
   {min,max}_nr_regions" adds features and addresses errors in DAMON's
   self testing code.

 - Gavin Shan has found a userspace-triggerable WARN in the pagecache
   code. The series "mm/filemap: Limit page cache size to that supported
   by xarray" addresses this. The series is marked cc:stable.

 - Chengming Zhou's series "mm/ksm: cmp_and_merge_page() optimizations
   and cleanup" cleans up and slightly optimizes KSM.

 - Roman Gushchin has separated the memcg-v1 and memcg-v2 code - lots of
   code motion. The series (which also makes the memcg-v1 code
   Kconfigurable) are "mm: memcg: separate legacy cgroup v1 code and put
   under config option" and "mm: memcg: put cgroup v1-specific memcg
   data under CONFIG_MEMCG_V1"

 - Dan Schatzberg's series "Add swappiness argument to memory.reclaim"
   adds an additional feature to this cgroup-v2 control file.

 - The series "Userspace controls soft-offline pages" from Jiaqi Yan
   permits userspace to stop the kernel's automatic treatment of
   excessive correctable memory errors. In order to permit userspace to
   monitor and handle this situation.

 - Kefeng Wang's series "mm: migrate: support poison recover from
   migrate folio" teaches the kernel to appropriately handle migration
   from poisoned source folios rather than simply panicing.

 - SeongJae Park's series "Docs/damon: minor fixups and improvements"
   does those things.

 - In the series "mm/zsmalloc: change back to per-size_class lock"
   Chengming Zhou improves zsmalloc's scalability and memory
   utilization.

 - Vivek Kasireddy's series "mm/gup: Introduce memfd_pin_folios() for
   pinning memfd folios" makes the GUP code use FOLL_PIN rather than
   bare refcount increments. So these paes can first be moved aside if
   they reside in the movable zone or a CMA block.

 - Andrii Nakryiko has added a binary ioctl()-based API to
   /proc/pid/maps for much faster reading of vma information. The series
   is "query VMAs from /proc/<pid>/maps".

 - In the series "mm: introduce per-order mTHP split counters" Lance
   Yang improves the kernel's presentation of developer information
   related to multisize THP splitting.

 - Michael Ellerman has developed the series "Reimplement huge pages
   without hugepd on powerpc (8xx, e500, book3s/64)". This permits
   userspace to use all available huge page sizes.

 - In the series "revert unconditional slab and page allocator fault
   injection calls" Vlastimil Babka removes a performance-affecting and
   not very useful feature from slab fault injection.

* tag 'mm-stable-2024-07-21-14-50' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (411 commits)
  mm/mglru: fix ineffective protection calculation
  mm/zswap: fix a white space issue
  mm/hugetlb: fix kernel NULL pointer dereference when migrating hugetlb folio
  mm/hugetlb: fix possible recursive locking detected warning
  mm/gup: clear the LRU flag of a page before adding to LRU batch
  mm/numa_balancing: teach mpol_to_str about the balancing mode
  mm: memcg1: convert charge move flags to unsigned long long
  alloc_tag: fix page_ext_get/page_ext_put sequence during page splitting
  lib: reuse page_ext_data() to obtain codetag_ref
  lib: add missing newline character in the warning message
  mm/mglru: fix overshooting shrinker memory
  mm/mglru: fix div-by-zero in vmpressure_calc_level()
  mm/kmemleak: replace strncpy() with strscpy()
  mm, page_alloc: put should_fail_alloc_page() back behing CONFIG_FAIL_PAGE_ALLOC
  mm, slab: put should_failslab() back behind CONFIG_SHOULD_FAILSLAB
  mm: ignore data-race in __swap_writepage
  hugetlbfs: ensure generic_hugetlb_get_unmapped_area() returns higher address than mmap_min_addr
  mm: shmem: rename mTHP shmem counters
  mm: swap_state: use folio_alloc_mpol() in __read_swap_cache_async()
  mm/migrate: putback split folios when numa hint migration fails
  ...
2024-07-21 17:15:46 -07:00
Jason A. Donenfeld
9651fcedf7 mm: add MAP_DROPPABLE for designating always lazily freeable mappings
The vDSO getrandom() implementation works with a buffer allocated with a
new system call that has certain requirements:

- It shouldn't be written to core dumps.
  * Easy: VM_DONTDUMP.
- It should be zeroed on fork.
  * Easy: VM_WIPEONFORK.

- It shouldn't be written to swap.
  * Uh-oh: mlock is rlimited.
  * Uh-oh: mlock isn't inherited by forks.

- It shouldn't reserve actual memory, but it also shouldn't crash when
  page faulting in memory if none is available
  * Uh-oh: VM_NORESERVE means segfaults.

It turns out that the vDSO getrandom() function has three really nice
characteristics that we can exploit to solve this problem:

1) Due to being wiped during fork(), the vDSO code is already robust to
   having the contents of the pages it reads zeroed out midway through
   the function's execution.

2) In the absolute worst case of whatever contingency we're coding for,
   we have the option to fallback to the getrandom() syscall, and
   everything is fine.

3) The buffers the function uses are only ever useful for a maximum of
   60 seconds -- a sort of cache, rather than a long term allocation.

These characteristics mean that we can introduce VM_DROPPABLE, which
has the following semantics:

a) It never is written out to swap.
b) Under memory pressure, mm can just drop the pages (so that they're
   zero when read back again).
c) It is inherited by fork.
d) It doesn't count against the mlock budget, since nothing is locked.
e) If there's not enough memory to service a page fault, it's not fatal,
   and no signal is sent.

This way, allocations used by vDSO getrandom() can use:

    VM_DROPPABLE | VM_DONTDUMP | VM_WIPEONFORK | VM_NORESERVE

And there will be no problem with OOMing, crashing on overcommitment,
using memory when not in use, not wiping on fork(), coredumps, or
writing out to swap.

In order to let vDSO getrandom() use this, expose these via mmap(2) as
MAP_DROPPABLE.

Note that this involves removing the MADV_FREE special case from
sort_folio(), which according to Yu Zhao is unnecessary and will simply
result in an extra call to shrink_folio_list() in the worst case. The
chunk removed reenables the swapbacked flag, which we don't want for
VM_DROPPABLE, and we can't conditionalize it here because there isn't a
vma reference available.

Finally, the provided self test ensures that this is working as desired.

Cc: linux-mm@kvack.org
Acked-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2024-07-19 20:22:12 +02:00