This will be needed in order to implement the get_parent export op
for nfsd.
Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
This helper will allow to find an existing NFS inode by the file handle
and fattr.
Signed-off-by: Peng Tao <tao.peng@primarydata.com>
[hch: split from a larger patch]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Transparent State Migration copies a client's lease state from the
server where a filesystem used to reside to the server where it now
resides. When an NFSv4.1 client first contacts that destination
server, it uses EXCHANGE_ID to detect trunking relationships.
The lease that was copied there is returned to that client, but the
destination server sets EXCHGID4_FLAG_CONFIRMED_R when replying to
the client. This is because the lease was confirmed on the source
server (before it was copied).
Normally, when CONFIRMED_R is set, a client purges the lease and
creates a new one. However, that throws away the entire benefit of
Transparent State Migration.
Therefore, the client must not purge that lease when it is possible
that Transparent State Migration has occurred.
Reported-by: Xuan Qi <xuan.qi@oracle.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Tested-by: Xuan Qi <xuan.qi@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
If the page cache is being flushed, then we want to ensure that we
do start a commit once the pages are done being flushed.
If we just wait until all I/O is done to that file, we can end up
livelocking until the balance_dirty_pages() mechanism puts its
foot down and forces I/O to stop.
So instead we do more or less the same thing that O_DIRECT does,
and set up a counter to tell us when the flush is done,
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Remove the 'layout_private' fields that were only used by the pNFS OSD
layout driver.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
An interrupted rename will leave the old dentry behind if the rename
succeeds. Fix this by forcing a lookup the next time through
->d_revalidate.
A previous attempt at solving this problem took the approach to complete
the work of the rename asynchronously, however that approach was wrong
since it would allow the d_move() to occur after the directory's i_mutex
had been dropped by the original process.
Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
NFS uses some int, and unsigned int :1, and bool as flags in structs and
args. Assert the preference for uniformly replacing these with the bool
type.
Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
struct svc_procinfo contains function pointers, and marking it as
constant avoids it being able to be used as an attach vector for
code injections.
Signed-off-by: Christoph Hellwig <hch@lst.de>
pc_count is the only writeable memeber of struct svc_procinfo, which is
a good candidate to be const-ified as it contains function pointers.
This patch moves it into out out struct svc_procinfo, and into a
separate writable array that is pointed to by struct svc_version.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Drop the resp argument as it can trivially be derived from the rqstp
argument. With that all functions now have the same prototype, and we
can remove the unsafe casting to kxdrproc_t.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Trond Myklebust <trond.myklebust@primarydata.com>
Drop the argp argument as it can trivially be derived from the rqstp
argument. With that all functions now have the same prototype, and we
can remove the unsafe casting to kxdrproc_t.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Drop the p and resp arguments as they are always NULL or can trivially
be derived from the rqstp argument. With that all functions now have the
same prototype, and we can remove the unsafe casting to kxdrproc_t.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Drop the argp and resp arguments as they can trivially be derived from
the rqstp argument. With that all functions now have the same prototype,
and we can remove the unsafe casting to svc_procfunc as well as the
svc_procfunc typedef itself.
Signed-off-by: Christoph Hellwig <hch@lst.de>
struct rpc_procinfo contains function pointers, and marking it as
constant avoids it being able to be used as an attach vector for
code injections.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Trond Myklebust <trond.myklebust@primarydata.com>
p_count is the only writeable memeber of struct rpc_procinfo, which is
a good candidate to be const-ified as it contains function pointers.
This patch moves it into out out struct rpc_procinfo, and into a
separate writable array that is pointed to by struct rpc_version and
indexed by p_statidx.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Pass struct rpc_request as the first argument instead of an untyped blob.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Acked-by: Trond Myklebust <trond.myklebust@primarydata.com>
Pass struct rpc_request as the first argument instead of an untyped blob,
and mark the data object as const.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Pull key subsystem fixes from James Morris:
"Here are a bunch of fixes for Linux keyrings, including:
- Fix up the refcount handling now that key structs use the
refcount_t type and the refcount_t ops don't allow a 0->1
transition.
- Fix a potential NULL deref after error in x509_cert_parse().
- Don't put data for the crypto algorithms to use on the stack.
- Fix the handling of a null payload being passed to add_key().
- Fix incorrect cleanup an uninitialised key_preparsed_payload in
key_update().
- Explicit sanitisation of potentially secure data before freeing.
- Fixes for the Diffie-Helman code"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security: (23 commits)
KEYS: fix refcount_inc() on zero
KEYS: Convert KEYCTL_DH_COMPUTE to use the crypto KPP API
crypto : asymmetric_keys : verify_pefile:zero memory content before freeing
KEYS: DH: add __user annotations to keyctl_kdf_params
KEYS: DH: ensure the KDF counter is properly aligned
KEYS: DH: don't feed uninitialized "otherinfo" into KDF
KEYS: DH: forbid using digest_null as the KDF hash
KEYS: sanitize key structs before freeing
KEYS: trusted: sanitize all key material
KEYS: encrypted: sanitize all key material
KEYS: user_defined: sanitize key payloads
KEYS: sanitize add_key() and keyctl() key payloads
KEYS: fix freeing uninitialized memory in key_update()
KEYS: fix dereferencing NULL payload with nonzero length
KEYS: encrypted: use constant-time HMAC comparison
KEYS: encrypted: fix race causing incorrect HMAC calculations
KEYS: encrypted: fix buffer overread in valid_master_desc()
KEYS: encrypted: avoid encrypting/decrypting stack buffers
KEYS: put keyring if install_session_keyring_to_cred() fails
KEYS: Delete an error message for a failed memory allocation in get_derived_key()
...
Commit abb2ea7dfd82 ("compiler, clang: suppress warning for unused
static inline functions") just caused more warnings due to re-defining
the 'inline' macro.
So undef it before re-defining it, and also add the 'notrace' attribute
like the gcc version that this is overriding does.
Maybe this makes clang happier.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
failures.
-----BEGIN PGP SIGNATURE-----
iQEzBAABCAAdFiEEK2m5VNv+CHkogTfJ8vlZVpUNgaMFAlk9it4ACgkQ8vlZVpUN
gaNE2wgAiuo9pHO5cUzRhP5HG8Jz4vE2l6mpuPq2JbhT+xGFbvjX+UhA+DN6Cw35
EK+MnBC6h2wFoQrEOLbavNWc94nb6HZWw2riheK4sst80hBpeclwInCVCw1DLmu6
+Nx8fzXVqjSf57Qi8CR09AGovSFBgfAJFi8aJTe8KXaSRPx48bWFxK6glgIG5gRw
VEOyEg5kPRYoUNA8ewsunC67V32ljYF2IZSzTTlrcqaLsXi+SWeiJ2hceYfgI0qz
fZB1EFBvmGBsdsFM2SHiJpME6fzMEQqx7oTyNC8DhCxMRVd29WjxeqCwcU4nV0Q5
jJaCKJftJ/q/eLKn7ksezhoL0A96BA==
=Z9eH
-----END PGP SIGNATURE-----
Merge tag 'ext4_for_linus_stable' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4
Pull ext4 fixes from Ted Ts'o:
"Fix various bug fixes in ext4 caused by races and memory allocation
failures"
* tag 'ext4_for_linus_stable' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4:
ext4: fix fdatasync(2) after extent manipulation operations
ext4: fix data corruption for mmap writes
ext4: fix data corruption with EXT4_GET_BLOCKS_ZERO
ext4: fix quota charging for shared xattr blocks
ext4: remove redundant check for encrypted file on dio write path
ext4: remove unused d_name argument from ext4_search_dir() et al.
ext4: fix off-by-one error when writing back pages before dio read
ext4: fix off-by-one on max nr_pages in ext4_find_unwritten_pgoff()
ext4: keep existing extra fields when inode expands
ext4: handle the rest of ext4_mb_load_buddy() ENOMEM errors
ext4: fix off-by-in in loop termination in ext4_find_unwritten_pgoff()
ext4: fix SEEK_HOLE
jbd2: preserve original nofs flag during journal restart
ext4: clear lockdep subtype for quota files on quota off
Pull RCU fixes from Ingo Molnar:
"Fix an SRCU bug affecting KVM IRQ injection"
* 'rcu-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
srcu: Allow use of Classic SRCU from both process and interrupt context
srcu: Allow use of Tiny/Tree SRCU from both process and interrupt context
Including:
* Another compile-fix for my header cleanup
* A couple of fixes for the recently merged IOMMU probe
deferal code
* Includes fixes for ACPI/IORT code necessary with
IOMMU probe deferal
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v2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=6dZB
-----END PGP SIGNATURE-----
Merge tag 'iommu-fixes-v4.12-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu
Pull IOMMU fixes from Joerg Roedel:
- another compile-fix for my header cleanup
- a couple of fixes for the recently merged IOMMU probe deferal code
- fixes for ACPI/IORT code necessary with IOMMU probe deferal
* tag 'iommu-fixes-v4.12-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu:
arm: dma-mapping: Reset the device's dma_ops
ACPI/IORT: Move the check to get iommu_ops from translated fwspec
ARM: dma-mapping: Don't tear down third-party mappings
ACPI/IORT: Ignore all errors except EPROBE_DEFER
iommu/of: Ignore all errors except EPROBE_DEFER
iommu/of: Fix check for returning EPROBE_DEFER
iommu/dma: Fix function declaration
Pull block fixes from Jens Axboe:
"A set of fixes in the area of block IO, that should go into the next
-rc release. This contains:
- An OOPS fix from Dmitry, fixing a regression with the bio integrity
code in this series.
- Fix truncation of elevator io context cache name, from Eric
Biggers.
- NVMe pull from Christoph includes FC fixes from James, APST
fixes/tweaks from Kai-Heng, removal fix from Rakesh, and an RDMA
fix from Sagi.
- Two tweaks for the block throttling code. One from Joseph Qi,
fixing an oops from the timer code, and one from Shaohua, improving
the behavior on rotatonal storage.
- Two blk-mq fixes from Ming, fixing corner cases with the direct
issue code.
- Locking fix for bfq cgroups from Paolo"
* 'for-linus' of git://git.kernel.dk/linux-block:
block, bfq: access and cache blkg data only when safe
Fix loop device flush before configure v3
blk-throttle: set default latency baseline for harddisk
blk-throttle: fix NULL pointer dereference in throtl_schedule_pending_timer
nvme: relax APST default max latency to 100ms
nvme: only consider exit latency when choosing useful non-op power states
nvme-fc: fix missing put reference on controller create failure
nvme-fc: on lldd/transport io error, terminate association
nvme-rdma: fast fail incoming requests while we reconnect
nvme-pci: fix multiple ctrl removal scheduling
nvme: fix hang in remove path
elevator: fix truncation of icq_cache_name
blk-mq: fix direct issue
blk-mq: pass correct hctx to blk_mq_try_issue_directly
bio-integrity: Do not allocate integrity context for bio w/o data
Pull RCU fix from Paul E. McKenney:
" This series enables srcu_read_lock() and srcu_read_unlock() to be used from
interrupt handlers, which fixes a bug in KVM's use of SRCU in delivery
of interrupts to guest OSes. "
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: James Morris <james.l.morris@oracle.com>
While a 'struct key' itself normally does not contain sensitive
information, Documentation/security/keys.txt actually encourages this:
"Having a payload is not required; and the payload can, in fact,
just be a value stored in the struct key itself."
In case someone has taken this advice, or will take this advice in the
future, zero the key structure before freeing it. We might as well, and
as a bonus this could make it a bit more difficult for an adversary to
determine which keys have recently been in use.
This is safe because the key_jar cache does not use a constructor.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>
- Revert a recent commit that attempted to avoid spurious wakeups
from suspend-to-idle via ACPI SCI, but introduced regressions on
some systems (Rafael Wysocki).
We will get back to the problem it tried to address in the next
cycle.
- Fix a possible division by 0 during intel_pstate initialization
due to a missing check (Rafael Wysocki).
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v2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=oWdX
-----END PGP SIGNATURE-----
Merge tag 'pm-4.12-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull power management fixes from Rafael Wysocki:
"These revert one problematic commit related to system sleep and fix
one recent intel_pstate regression.
Specifics:
- Revert a recent commit that attempted to avoid spurious wakeups
from suspend-to-idle via ACPI SCI, but introduced regressions on
some systems (Rafael Wysocki).
We will get back to the problem it tried to address in the next
cycle.
- Fix a possible division by 0 during intel_pstate initialization
due to a missing check (Rafael Wysocki)"
* tag 'pm-4.12-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
Revert "ACPI / sleep: Ignore spurious SCI wakeups from suspend-to-idle"
cpufreq: intel_pstate: Avoid division by 0 in min_perf_pct_min()
Linu Cherian reported a WARN in cleanup_srcu_struct() when shutting
down a guest running iperf on a VFIO assigned device. This happens
because irqfd_wakeup() calls srcu_read_lock(&kvm->irq_srcu) in interrupt
context, while a worker thread does the same inside kvm_set_irq(). If the
interrupt happens while the worker thread is executing __srcu_read_lock(),
updates to the Classic SRCU ->lock_count[] field or the Tree SRCU
->srcu_lock_count[] field can be lost.
The docs say you are not supposed to call srcu_read_lock() and
srcu_read_unlock() from irq context, but KVM interrupt injection happens
from (host) interrupt context and it would be nice if SRCU supported the
use case. KVM is using SRCU here not really for the "sleepable" part,
but rather due to its IPI-free fast detection of grace periods. It is
therefore not desirable to switch back to RCU, which would effectively
revert commit 719d93cd5f5c ("kvm/irqchip: Speed up KVM_SET_GSI_ROUTING",
2014-01-16).
However, the docs are overly conservative. You can have an SRCU instance
only has users in irq context, and you can mix process and irq context
as long as process context users disable interrupts. In addition,
__srcu_read_unlock() actually uses this_cpu_dec() on both Tree SRCU and
Classic SRCU. For those two implementations, only srcu_read_lock()
is unsafe.
When Classic SRCU's __srcu_read_unlock() was changed to use this_cpu_dec(),
in commit 5a41344a3d83 ("srcu: Simplify __srcu_read_unlock() via
this_cpu_dec()", 2012-11-29), __srcu_read_lock() did two increments.
Therefore it kept __this_cpu_inc(), with preempt_disable/enable in
the caller. Tree SRCU however only does one increment, so on most
architectures it is more efficient for __srcu_read_lock() to use
this_cpu_inc(), and any performance differences appear to be down in
the noise.
Cc: stable@vger.kernel.org
Fixes: 719d93cd5f5c ("kvm/irqchip: Speed up KVM_SET_GSI_ROUTING")
Reported-by: Linu Cherian <linuc.decode@gmail.com>
Suggested-by: Linu Cherian <linuc.decode@gmail.com>
Cc: kvm@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Changes include:
- Fix an issue with migrating GICv2 VMs on GICv3 systems.
- Squashed a bug for gicv3 when figuring out preemption levels.
- Fix a potential null pointer derefence in KVM happening under memory
pressure.
- Maintain RES1 bits in the SCTLR_EL2 to make sure KVM works on new
architecture revisions.
- Allow unaligned accesses at EL2/HYP
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1
iQEcBAABAgAGBQJZODC6AAoJEEtpOizt6ddy7qsH/RakZzHHlPcIFk+VPhK4AvIV
ke6y1IznIVVv024geILb2NyF2pZoSUROxk1NF0wBIWM4ryjPm7oYgK7TTLyxkiX0
00gNxWpRRerCSxfh11a28tQywc7ATlw0yFpogGvbbHG9qEMX1NaGP/CNFK5us0LT
dw3y7jIZounlHlHu0W85AE27Osn5anFPHQnEtvJlUsM7WkIQf765EIfttXGUKRDZ
szmwuFAhdsSeIfo23LNXj87WAn6uP/37qRUmNXnxSya4u5urXa4qlOM5Hvg6agw2
K6LdpDXF/FnHhiT+b/xMTRPPivy4rXJZTpP51shl5GqKE2gI0tbhsHwJJ5Di/Aw=
=3xSf
-----END PGP SIGNATURE-----
Merge tag 'kvm-arm-for-v4.12-rc5-take2' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD
KVM/ARM Fixes for v4.12-rc5 - Take 2
Changes include:
- Fix an issue with migrating GICv2 VMs on GICv3 systems.
- Squashed a bug for gicv3 when figuring out preemption levels.
- Fix a potential null pointer derefence in KVM happening under memory
pressure.
- Maintain RES1 bits in the SCTLR_EL2 to make sure KVM works on new
architecture revisions.
- Allow unaligned accesses at EL2/HYP
Revert commit eed4d47efe95 (ACPI / sleep: Ignore spurious SCI wakeups
from suspend-to-idle) as it turned out to be premature and triggered
a number of different issues on various systems.
That includes, but is not limited to, premature suspend-to-RAM aborts
on Dell XPS 13 (9343) reported by Dominik.
The issue the commit in question attempted to address is real and
will need to be taken care of going forward, but evidently more work
is needed for this purpose.
Reported-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Pull networking fixes from David Miller:
1) Made TCP congestion control documentation match current reality,
from Anmol Sarma.
2) Various build warning and failure fixes from Arnd Bergmann.
3) Fix SKB list leak in ipv6_gso_segment().
4) Use after free in ravb driver, from Eugeniu Rosca.
5) Don't use udp_poll() in ping protocol driver, from Eric Dumazet.
6) Don't crash in PCI error recovery of cxgb4 driver, from Guilherme
Piccoli.
7) _SRC_NAT_DONE_BIT needs to be cleared using atomics, from Liping
Zhang.
8) Use after free in vxlan deletion, from Mark Bloch.
9) Fix ordering of NAPI poll enabled in ethoc driver, from Max
Filippov.
10) Fix stmmac hangs with TSO, from Niklas Cassel.
11) Fix crash in CALIPSO ipv6, from Richard Haines.
12) Clear nh_flags properly on mpls link up. From Roopa Prabhu.
13) Fix regression in sk_err socket error queue handling, noticed by
ping applications. From Soheil Hassas Yeganeh.
14) Update mlx4/mlx5 MAINTAINERS information.
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (78 commits)
net: stmmac: fix a broken u32 less than zero check
net: stmmac: fix completely hung TX when using TSO
net: ethoc: enable NAPI before poll may be scheduled
net: bridge: fix a null pointer dereference in br_afspec
ravb: Fix use-after-free on `ifconfig eth0 down`
net/ipv6: Fix CALIPSO causing GPF with datagram support
net: stmmac: ensure jumbo_frm error return is correctly checked for -ve value
Revert "sit: reload iphdr in ipip6_rcv"
i40e/i40evf: proper update of the page_offset field
i40e: Fix state flags for bit set and clean operations of PF
iwlwifi: fix host command memory leaks
iwlwifi: fix min API version for 7265D, 3168, 8000 and 8265
iwlwifi: mvm: clear new beacon command template struct
iwlwifi: mvm: don't fail when removing a key from an inexisting sta
iwlwifi: pcie: only use d0i3 in suspend/resume if system_pm is set to d0i3
iwlwifi: mvm: fix firmware debug restart recording
iwlwifi: tt: move ucode_loaded check under mutex
iwlwifi: mvm: support ibss in dqa mode
iwlwifi: mvm: Fix command queue number on d0i3 flow
iwlwifi: mvm: rs: start using LQ command color
...
GCC explicitly does not warn for unused static inline functions for
-Wunused-function. The manual states:
Warn whenever a static function is declared but not defined or
a non-inline static function is unused.
Clang does warn for static inline functions that are unused.
It turns out that suppressing the warnings avoids potentially complex
#ifdef directives, which also reduces LOC.
Suppress the warning for clang.
Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
gcc 7.1 reports the following warning:
block/elevator.c: In function ‘elv_register’:
block/elevator.c:898:5: warning: ‘snprintf’ output may be truncated before the last format character [-Wformat-truncation=]
"%s_io_cq", e->elevator_name);
^~~~~~~~~~
block/elevator.c:897:3: note: ‘snprintf’ output between 7 and 22 bytes into a destination of size 21
snprintf(e->icq_cache_name, sizeof(e->icq_cache_name),
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
"%s_io_cq", e->elevator_name);
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The bug is that the name of the icq_cache is 6 characters longer than
the elevator name, but only ELV_NAME_MAX + 5 characters were reserved
for it --- so in the case of a maximum-length elevator name, the 'q'
character in "_io_cq" would be truncated by snprintf(). Fix it by
reserving ELV_NAME_MAX + 6 characters instead.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Bart Van Assche <Bart.VanAssche@sandisk.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
-----BEGIN PGP SIGNATURE-----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=+jBV
-----END PGP SIGNATURE-----
Merge tag 'media/v4.12-2' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media
Pull media fixes from Mauro Carvalho Chehab:
"Some bug fixes:
- Don't fail build if atomisp has warnings
- Some CEC Kconfig changes to allow it to be used by DRM without
media dependencies
- A race fix at RC initialization code
- A driver fix at rainshadow-cec
IMHO, the one that affects most people in this series is a build fix:
if you try to build the Kernel with W=1 or using gcc7 and
all[yes|mod]config, build will fail due to -Werror at atomisp
makefiles"
* tag 'media/v4.12-2' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media:
[media] rc-core: race condition during ir_raw_event_register()
[media] cec: drop MEDIA_CEC_DEBUG
[media] cec: rename MEDIA_CEC_NOTIFIER to CEC_NOTIFIER
[media] cec: select CEC_CORE instead of depend on it
[media] rainshadow-cec: ensure exit_loop is intialized
[media] atomisp: don't treat warnings as errors
Pull cgroup fixes from Tejun Heo:
"Two cgroup fixes. One to address RCU delay of cpuset removal affecting
userland visible behaviors. The other fixes a race condition between
controller disable and cgroup removal"
* 'for-4.12-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
cpuset: consider dying css as offline
cgroup: Prevent kill_css() from being called more than once
Update tcp.txt to fix mandatory congestion control ops and default
CCA selection. Also, fix comment in tcp.h for undo_cwnd.
Signed-off-by: Anmol Sarma <me@anmolsarma.in>
Signed-off-by: David S. Miller <davem@davemloft.net>
Our previous patch (cited below) introduced a regression
for RAW Eth QPs.
Fix it by checking if the QP number provided by user-space
exists, hence allowing steering rules to be added for valid
QPs only.
Fixes: 89c557687a32 ("net/mlx4_en: Avoid adding steering rules with invalid ring")
Reported-by: Or Gerlitz <gerlitz.or@gmail.com>
Signed-off-by: Talat Batheesh <talatb@mellanox.com>
Signed-off-by: Tariq Toukan <tariqt@mellanox.com>
Acked-by: Or Gerlitz <ogerlitz@mellanox.com>
Reviewed-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Alexander reported various KASAN messages triggered in recent kernels
The problem is that ping sockets should not use udp_poll() in the first
place, and recent changes in UDP stack finally exposed this old bug.
Fixes: c319b4d76b9e ("net: ipv4: add IPPROTO_ICMP socket kind")
Fixes: 6d0bfe226116 ("net: ipv6: Add IPv6 support to the ping socket.")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Sasha Levin <alexander.levin@verizon.com>
Cc: Solar Designer <solar@openwall.com>
Cc: Vasiliy Kulikov <segoon@openwall.com>
Cc: Lorenzo Colitti <lorenzo@google.com>
Acked-By: Lorenzo Colitti <lorenzo@google.com>
Tested-By: Lorenzo Colitti <lorenzo@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This config option is strictly speaking independent of the
media subsystem since it can be used by drm as well.
Besides, it looks odd when drivers select CEC_CORE and
MEDIA_CEC_NOTIFIER, that's inconsistent naming.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
- Multiple i40iw, nes, iw_cxgb4, hfi1, qib, mlx4, mlx5 fixes
- A few upper layer protocol fixes (IPoIB, iSER, SRP)
- A modest number of core fixes
-----BEGIN PGP SIGNATURE-----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=X6Rg
-----END PGP SIGNATURE-----
Merge tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dledford/rdma
Pull rdma fixes from Doug Ledford:
"For the most part this is just a minor -rc cycle for the rdma
subsystem. Even given that this is all of the -rc patches since the
merge window closed, it's still only about 25 patches:
- Multiple i40iw, nes, iw_cxgb4, hfi1, qib, mlx4, mlx5 fixes
- A few upper layer protocol fixes (IPoIB, iSER, SRP)
- A modest number of core fixes"
* tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dledford/rdma: (26 commits)
RDMA/SA: Fix kernel panic in CMA request handler flow
RDMA/umem: Fix missing mmap_sem in get umem ODP call
RDMA/core: not to set page dirty bit if it's already set.
RDMA/uverbs: Declare local function static and add brackets to sizeof
RDMA/netlink: Reduce exposure of RDMA netlink functions
RDMA/srp: Fix NULL deref at srp_destroy_qp()
RDMA/IPoIB: Limit the ipoib_dev_uninit_default scope
RDMA/IPoIB: Replace netdev_priv with ipoib_priv for ipoib_get_link_ksettings
RDMA/qedr: add null check before pointer dereference
RDMA/mlx5: set UMR wqe fence according to HCA cap
net/mlx5: Define interface bits for fencing UMR wqe
RDMA/mlx4: Fix MAD tunneling when SRIOV is enabled
RDMA/qib,hfi1: Fix MR reference count leak on write with immediate
RDMA/hfi1: Defer setting VL15 credits to link-up interrupt
RDMA/hfi1: change PCI bar addr assignments to Linux API functions
RDMA/hfi1: fix array termination by appending NULL to attr array
RDMA/iw_cxgb4: fix the calculation of ipv6 header size
RDMA/iw_cxgb4: calculate t4_eq_status_entries properly
RDMA/iw_cxgb4: Avoid touch after free error in ARP failure handlers
RDMA/nes: ACK MPA Reply frame
...
Merge misc fixes from Andrew Morton:
"15 fixes"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
scripts/gdb: make lx-dmesg command work (reliably)
mm: consider memblock reservations for deferred memory initialization sizing
mm/hugetlb: report -EHWPOISON not -EFAULT when FOLL_HWPOISON is specified
mlock: fix mlock count can not decrease in race condition
mm/migrate: fix refcount handling when !hugepage_migration_supported()
dax: fix race between colliding PMD & PTE entries
mm: avoid spurious 'bad pmd' warning messages
mm/page_alloc.c: make sure OOM victim can try allocations with no watermarks once
pcmcia: remove left-over %Z format
slub/memcg: cure the brainless abuse of sysfs attributes
initramfs: fix disabling of initramfs (and its compression)
mm: clarify why we want kmalloc before falling backto vmallock
frv: declare jiffies to be located in the .data section
include/linux/gfp.h: fix ___GFP_NOLOCKDEP value
ksm: prevent crash after write_protect_page fails
We have seen an early OOM killer invocation on ppc64 systems with
crashkernel=4096M:
kthreadd invoked oom-killer: gfp_mask=0x16040c0(GFP_KERNEL|__GFP_COMP|__GFP_NOTRACK), nodemask=7, order=0, oom_score_adj=0
kthreadd cpuset=/ mems_allowed=7
CPU: 0 PID: 2 Comm: kthreadd Not tainted 4.4.68-1.gd7fe927-default #1
Call Trace:
dump_stack+0xb0/0xf0 (unreliable)
dump_header+0xb0/0x258
out_of_memory+0x5f0/0x640
__alloc_pages_nodemask+0xa8c/0xc80
kmem_getpages+0x84/0x1a0
fallback_alloc+0x2a4/0x320
kmem_cache_alloc_node+0xc0/0x2e0
copy_process.isra.25+0x260/0x1b30
_do_fork+0x94/0x470
kernel_thread+0x48/0x60
kthreadd+0x264/0x330
ret_from_kernel_thread+0x5c/0xa4
Mem-Info:
active_anon:0 inactive_anon:0 isolated_anon:0
active_file:0 inactive_file:0 isolated_file:0
unevictable:0 dirty:0 writeback:0 unstable:0
slab_reclaimable:5 slab_unreclaimable:73
mapped:0 shmem:0 pagetables:0 bounce:0
free:0 free_pcp:0 free_cma:0
Node 7 DMA free:0kB min:0kB low:0kB high:0kB active_anon:0kB inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:0kB isolated(anon):0kB isolated(file):0kB present:52428800kB managed:110016kB mlocked:0kB dirty:0kB writeback:0kB mapped:0kB shmem:0kB slab_reclaimable:320kB slab_unreclaimable:4672kB kernel_stack:1152kB pagetables:0kB unstable:0kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB writeback_tmp:0kB pages_scanned:0 all_unreclaimable? yes
lowmem_reserve[]: 0 0 0 0
Node 7 DMA: 0*64kB 0*128kB 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB 0*8192kB 0*16384kB = 0kB
0 total pagecache pages
0 pages in swap cache
Swap cache stats: add 0, delete 0, find 0/0
Free swap = 0kB
Total swap = 0kB
819200 pages RAM
0 pages HighMem/MovableOnly
817481 pages reserved
0 pages cma reserved
0 pages hwpoisoned
the reason is that the managed memory is too low (only 110MB) while the
rest of the the 50GB is still waiting for the deferred intialization to
be done. update_defer_init estimates the initial memoty to initialize
to 2GB at least but it doesn't consider any memory allocated in that
range. In this particular case we've had
Reserving 4096MB of memory at 128MB for crashkernel (System RAM: 51200MB)
so the low 2GB is mostly depleted.
Fix this by considering memblock allocations in the initial static
initialization estimation. Move the max_initialise to
reset_deferred_meminit and implement a simple memblock_reserved_memory
helper which iterates all reserved blocks and sums the size of all that
start below the given address. The cumulative size is than added on top
of the initial estimation. This is still not ideal because
reset_deferred_meminit doesn't consider holes and so reservation might
be above the initial estimation whihch we ignore but let's make the
logic simpler until we really need to handle more complicated cases.
Fixes: 3a80a7fa7989 ("mm: meminit: initialise a subset of struct pages if CONFIG_DEFERRED_STRUCT_PAGE_INIT is set")
Link: http://lkml.kernel.org/r/20170531104010.GI27783@dhcp22.suse.cz
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Tested-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: <stable@vger.kernel.org> [4.2+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
KVM uses get_user_pages() to resolve its stage2 faults. KVM sets the
FOLL_HWPOISON flag causing faultin_page() to return -EHWPOISON when it
finds a VM_FAULT_HWPOISON. KVM handles these hwpoison pages as a
special case. (check_user_page_hwpoison())
When huge pages are involved, this doesn't work so well.
get_user_pages() calls follow_hugetlb_page(), which stops early if it
receives VM_FAULT_HWPOISON from hugetlb_fault(), eventually returning
-EFAULT to the caller. The step to map this to -EHWPOISON based on the
FOLL_ flags is missing. The hwpoison special case is skipped, and
-EFAULT is returned to user-space, causing Qemu or kvmtool to exit.
Instead, move this VM_FAULT_ to errno mapping code into a header file
and use it from faultin_page() and follow_hugetlb_page().
With this, KVM works as expected.
This isn't a problem for arm64 today as we haven't enabled
MEMORY_FAILURE, but I can't see any reason this doesn't happen on x86
too, so I think this should be a fix. This doesn't apply earlier than
stable's v4.11.1 due to all sorts of cleanup.
[james.morse@arm.com: add vm_fault_to_errno() call to faultin_page()]
suggested.
Link: http://lkml.kernel.org/r/20170525171035.16359-1-james.morse@arm.com
[akpm@linux-foundation.org: coding-style fixes]
Link: http://lkml.kernel.org/r/20170524160900.28786-1-james.morse@arm.com
Signed-off-by: James Morse <james.morse@arm.com>
Acked-by: Punit Agrawal <punit.agrawal@arm.com>
Acked-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
Cc: <stable@vger.kernel.org> [4.11.1+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit 7c30f352c852 ("jiffies.h: declare jiffies and jiffies_64 with
____cacheline_aligned_in_smp") removed a section specification from the
jiffies declaration that caused conflicts on some platforms.
Unfortunately this change broke the build for frv:
kernel/built-in.o: In function `__do_softirq': (.text+0x6460): relocation truncated to fit: R_FRV_GPREL12 against symbol
`jiffies' defined in *ABS* section in .tmp_vmlinux1
kernel/built-in.o: In function `__do_softirq': (.text+0x6574): relocation truncated to fit: R_FRV_GPREL12 against symbol
`jiffies' defined in *ABS* section in .tmp_vmlinux1
kernel/built-in.o: In function `pwq_activate_delayed_work': workqueue.c:(.text+0x15b9c): relocation truncated to fit: R_FRV_GPREL12 against
symbol `jiffies' defined in *ABS* section in .tmp_vmlinux1
...
Add __jiffy_arch_data to the declaration of jiffies and use it on frv to
include the section specification. For all other platforms
__jiffy_arch_data (currently) has no effect.
Fixes: 7c30f352c852 ("jiffies.h: declare jiffies and jiffies_64 with ____cacheline_aligned_in_smp")
Link: http://lkml.kernel.org/r/20170516221333.177280-1-mka@chromium.org
Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
Reported-by: Guenter Roeck <linux@roeck-us.net>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: David Howells <dhowells@redhat.com>
Cc: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Igor Stoppa has noticed that __GFP_NOLOCKDEP can use a lower bit. At
the time commit 7e7844226f10 ("lockdep: allow to disable reclaim lockup
detection") was written we still had __GFP_OTHER_NODE but I have removed
it in commit 41b6167e8f74 ("mm: get rid of __GFP_OTHER_NODE") and forgot
to lower the bit value.
The current value is outside of __GFP_BITS_SHIFT so it cannot be used
actually.
Fixes: 7e7844226f10 ("lockdep: allow to disable reclaim lockup detection")
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reported-by: Igor Stoppa <igor.stoppa@nokia.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-----BEGIN PGP SIGNATURE-----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=RiLR
-----END PGP SIGNATURE-----
Merge tag 'drm-dp-quirk-for-v4.12-rc4' of git://people.freedesktop.org/~airlied/linux
Pull drm displayport quirk support:
"DP quirk for usb c dongles.
As mentioned I have a separate request for fixing a regression, but
also keeping the broken hw working, for certain USB-C DP adapters they
require a minimised n/m parameters, but an attempt to do this
generically has failed, we need to quirk these specific adapters.
However doing it generically regressed some eDP panels.
This pull adds the infrastructure and a quirk for the adapter"
* tag 'drm-dp-quirk-for-v4.12-rc4' of git://people.freedesktop.org/~airlied/linux:
drm/i915: Detect USB-C specific dongles before reducing M and N
drm/dp: start a DPCD based DP sink/branch device quirk database
drm/i915: use drm DP helper to read DPCD desc
drm/dp: add helper for reading DP sink/branch device desc from DPCD
