46580 Commits

Author SHA1 Message Date
Al Viro
f334bcd94b Merge remote-tracking branch 'ovl/misc' into work.misc 2016-10-08 11:00:01 -04:00
Al Viro
73e8fb2d59 Merge branch 'work.const-qstr' into work.misc 2016-10-08 10:44:55 -04:00
Al Viro
33e09f0ee7 Merge branch 'work.iget' into work.misc 2016-10-08 10:44:37 -04:00
Luis de Bethencourt
a17e7d2010 befs: befs: fix style issues in datastream.c
Fixing the following checkpatch.pl errors:

ERROR: "foo * bar" should be "foo *bar"
+                            befs_blocknr_t blockno, befs_block_run * run);

WARNING: Missing a blank line after declarations
+       struct buffer_head *bh;
+       befs_debug(sb, "---> %s length: %llu", __func__, len);

WARNING: Block comments use * on subsequent lines
+       /*
+          Double indir block, plus all the indirect blocks it maps.

(and other instances of these)

Signed-off-by: Luis de Bethencourt <luisbg@osg.samsung.com>
Signed-off-by: Salah Triki <salah.triki@gmail.com>
2016-10-08 10:01:36 +01:00
Luis de Bethencourt
a20af5f9ea befs: improve documentation in datastream.c
Convert function descriptions to kernel-doc style.

Signed-off-by: Luis de Bethencourt <luisbg@osg.samsung.com>
Signed-off-by: Salah Triki <salah.triki@gmail.com>
2016-10-08 10:01:36 +01:00
Luis de Bethencourt
d327e612bd befs: fix typos in datastream.c
Signed-off-by: Luis de Bethencourt <luisbg@osg.samsung.com>
Signed-off-by: Salah Triki <salah.triki@gmail.com>
2016-10-08 10:01:35 +01:00
Luis de Bethencourt
02d91f97fd befs: fix typos in btree.c
Fixing typos in kernel-doc function descriptions in fs/befs/btree.c.

Signed-off-by: Luis de Bethencourt <luisbg@osg.samsung.com>
Signed-off-by: Salah Triki <salah.triki@gmail.com>
2016-10-08 10:01:34 +01:00
Luis de Bethencourt
103c0fb340 befs: fix style issues in super.c
Fixing the following checkpatch.pl error:

ERROR: "foo * bar" should be "foo *bar"
+befs_load_sb(struct super_block *sb, befs_super_block * disk_sb)

And the following warnings:

WARNING: suspect code indent for conditional statements (8, 12)
+       if (disk_sb->fs_byte_order == BEFS_BYTEORDER_NATIVE_LE)
+           befs_sb->byte_order = BEFS_BYTESEX_LE;

WARNING: suspect code indent for conditional statements (8, 12)
+       else if (disk_sb->fs_byte_order == BEFS_BYTEORDER_NATIVE_BE)
+           befs_sb->byte_order = BEFS_BYTESEX_BE;

WARNING: break quoted strings at a space character
+               befs_error(sb, "blocksize(%u) cannot be larger"
+                          "than system pagesize(%lu)", befs_sb->block_size,

WARNING: line over 80 characters
+       if (befs_sb->log_start != befs_sb->log_end || befs_sb->flags == BEFS_DIRTY) {

Signed-off-by: Luis de Bethencourt <luisbg@osg.samsung.com>
Signed-off-by: Salah Triki <salah.triki@gmail.com>
2016-10-08 10:01:34 +01:00
Luis de Bethencourt
11674239f9 befs: fix comment style
The description of befs_load_sb was confusing the kernel-doc system since,
because it starts with /**, it thinks it will document the function with
kernel-doc formatting. Which it isn't.

Fix other comment style issues in the file while we are at it.

Signed-off-by: Luis de Bethencourt <luisbg@osg.samsung.com>
Signed-off-by: Salah Triki <salah.triki@gmail.com>
2016-10-08 10:01:33 +01:00
Luis de Bethencourt
bbe1bd0b6b befs: add check for ag_shift in superblock
ag_shift and blocks_per_ag contain the same information in different ways,
same as block_shift and block_size do. It is worth checking this two are
consistent, but since blocks_per_ag isn't documented as mandatory to use
some implementations of befs don't enforce this, so making it non-fatal if
they don't match and just having it as a warning.

Signed-off-by: Luis de Bethencourt <luisbg@osg.samsung.com>
Signed-off-by: Salah Triki <salah.triki@gmail.com>
2016-10-08 10:01:31 +01:00
Luis de Bethencourt
d1a8c70676 befs: dump inode_size superblock information
befs_dump_super_block() wasn't giving the inode_size information when
dumping all elements of the superblock. Add this element to have complete
information of the superblock.

Signed-off-by: Luis de Bethencourt <luisbg@osg.samsung.com>
Signed-off-by: Salah Triki <salah.triki@gmail.com>
2016-10-08 10:01:29 +01:00
Salah Triki
78f647c27f befs: remove unnecessary initialization
There is no need to init block, since it will be overwitten later by
iaddr2blockno().

Signed-off-by: Salah Triki <salah.triki@gmail.com>
Signed-off-by: Luis de Bethencourt <luisbg@osg.samsung.com>
2016-10-08 10:01:28 +01:00
Salah Triki
2ac636b4d0 befs: fix typo in befs_sb_info
Fixing jornal to Journal.

Signed-off-by: Salah Triki <salah.triki@gmail.com>
Signed-off-by: Luis de Bethencourt <luisbg@osg.samsung.com>
2016-10-08 10:01:27 +01:00
Salah Triki
6ea4558f9b befs: add flags field to validate superblock state
For validating superblock state, add flags field to befs_sb_info, read the state from the disk
and check if it is equal to BEFS_DIRTY.

Signed-off-by: Salah Triki <salah.triki@gmail.com>
Signed-off-by: Luis de Bethencourt <luisbg@osg.samsung.com>
2016-10-08 10:01:27 +01:00
Luis de Bethencourt
bb75e66627 befs: fix typo in befs_find_key
Fixing skeep to skip.

Signed-off-by: Luis de Bethencourt <luisbg@osg.samsung.com>
Signed-off-by: Salah Triki <salah.triki@gmail.com>
2016-10-08 10:01:26 +01:00
Luis de Bethencourt
672a8515ee befs: remove unused BEFS_BT_PARMATCH
befs_btree_find(), the only caller of befs_find_key(), only cares about if
the return from that function is BEFS_BT_MATCH or not. It never uses the
partial match given with BEFS_BT_PARMATCH. Make the overflow return clearer
by having BEFS_BT_OVERFLOW instead of BEFS_BT_PARMATCH.

Signed-off-by: Luis de Bethencourt <luisbg@osg.samsung.com>
Signed-off-by: Salah Triki <salah.triki@gmail.com>
2016-10-08 10:01:26 +01:00
Salah Triki
33c712b4fc fs: befs: remove ret variable
ret is initialized to -EIO and is never modified, so remove ret and use
-EIO directly.

Signed-off-by: Salah Triki <salah.triki@gmail.com>
Acked-by: Luis de Bethencourt <luisbg@osg.samsung.com>
2016-10-08 10:01:25 +01:00
Salah Triki
abcf911691 fs: befs: remove in vain variable assignment
There is no need to init res, since it will be overwitten later by
befs_fblock2brun().

Signed-off-by: Salah Triki <salah.triki@gmail.com>
Acked-by: Luis de Bethencourt <luisbg@osg.samsung.com>
2016-10-08 10:01:24 +01:00
Salah Triki
f30661035b fs: befs: remove unnecessary *befs_sb variable
Remove *befs_sb and just call BEFS_SB(sb) directly, since the returned
value by this function is only used once.

Signed-off-by: Salah Triki <salah.triki@gmail.com>
Acked-by: Luis de Bethencourt <luisbg@osg.samsung.com>
2016-10-08 10:01:23 +01:00
Salah Triki
143d2a615f fs: befs: remove useless initialization to zero
node_off is unconditionally set to bt_super.root_node_ptr, so no need to
init it to zero.

Signed-off-by: Salah Triki <salah.triki@gmail.com>
Acked-by: Luis de Bethencourt <luisbg@osg.samsung.com>
2016-10-08 10:01:23 +01:00
Salah Triki
88ff34446b fs: befs: remove in vain variable assignment
There is no need to set *value, it will be overwritten later.

Signed-off-by: Salah Triki <salah.triki@gmail.com>
Acked-by: Luis de Bethencourt <luisbg@osg.samsung.com>
2016-10-08 10:01:22 +01:00
Salah Triki
a26bc1adc7 fs: befs: Insert NULL inode to dentry
As VFS expects, lookup inserts NULL inode to dentry when the named inode
does not exist.

Signed-off-by: Salah Triki <salah.triki@gmail.com>
Acked-by: Luis de Bethencourt <luisbg@osg.samsung.com>
2016-10-08 10:01:21 +01:00
Salah Triki
d70ee4f2de fs: befs: Remove useless calls to brelse in befs_find_brun_dblindirect
The calls to brelse are useless since dbl_indir_block and indir_block
are NULL.

Signed-off-by: Salah Triki <salah.triki@gmail.com>
Acked-by: Luis de Bethencourt <luisbg@osg.samsung.com>
2016-10-08 10:01:20 +01:00
Salah Triki
4bb594329a fs: befs: Coding style fix
Constant has to be capitalized.

Signed-off-by: Salah Triki <salah.triki@gmail.com>
Acked-by: Luis de Bethencourt <luisbg@osg.samsung.com>
2016-10-08 10:01:20 +01:00
Salah Triki
d84e4a5a09 fs: befs: Remove redundant validation from befs_find_brun_direct
The only caller of befs_find_brun_direct is befs_fblock2brun, which
already validates that the block is within the range of direct blocks.
So remove the duplicate validation.

Signed-off-by: Salah Triki <salah.triki@gmail.com>
Acked-by: Luis de Bethencourt <luisbg@osg.samsung.com>
2016-10-08 10:01:19 +01:00
Luis de Bethencourt
2dfa8a6e56 befs: fix typo in befs_bt_read_node documentation
Fixing a grammatical error in the documentation.

Signed-off-by: Luis de Bethencourt <luisbg@osg.samsung.com>
2016-10-08 10:01:18 +01:00
Luis de Bethencourt
cfe0cb20e6 befs: in memory free_node_ptr and max_size never read
The only place the values of free_node_ptr and max_size are read is in
befs_dump_index_entry(), which both times it is called, it is passed the on
disk superblock. Removing assignment of unused values.

Signed-off-by: Luis de Bethencourt <luisbg@osg.samsung.com>
2016-10-08 10:01:17 +01:00
Luis de Bethencourt
4c3897cce0 befs: make consistent use of befs_error()
befs_error() is used in potential errors that could happen in befs to
provide informational log messages. befs_debug() is silent when
CONFIG_BEFS_DEBUG=no, and very verbose when switched on, which is why it is
used for general debugging but not for errors.

Fix a few cases where the befs debug utility usage isn't following the
expected pattern. To make sure we have consistent information in the logs.

Signed-off-by: Luis de Bethencourt <luisbg@osg.samsung.com>
2016-10-08 10:01:16 +01:00
Luis de Bethencourt
9ae51a32b1 befs: use simpler while loop
Replace goto with simpler while loop to make befs_readdir() more readable.

Signed-off-by: Luis de Bethencourt <luisbg@osg.samsung.com>
2016-10-08 10:01:16 +01:00
Luis de Bethencourt
50858ef96d befs: remove constant variable
Use macro directly instead of via assigning it to an unchanging variable.

Signed-off-by: Luis de Bethencourt <luisbg@osg.samsung.com>
Acked-by: Salah Triki <salah.triki@gmail.com>
2016-10-08 10:01:15 +01:00
Luis de Bethencourt
f7769f9cf9 befs: avoid dereferencing dentry twice
No need to dereference dentry twice to get the name when we already have
it stored in a local variable.

Signed-off-by: Luis de Bethencourt <luisbg@osg.samsung.com>
2016-10-08 10:01:15 +01:00
Luis de Bethencourt
39dcfd3b34 fs: befs: remove comment that confuses kernel-doc
This comment with a mysterious unfinished line confuses the kernel-doc
system since, because it starts with /**, it thinks it is documenting a
function.

Signed-off-by: Luis de Bethencourt <luisbg@osg.samsung.com>
2016-10-08 10:01:14 +01:00
Luis de Bethencourt
a64998504e fs: befs: check silent flag before logging error
Log error only when silent flag is not set.

Fixes: dbe6460388bc ("fs/befs/linuxvfs.c: check silent flag before logging errors")
Signed-off-by: Luis de Bethencourt <luisbg@osg.samsung.com>
Acked-by: Salah Triki <salah.triki@gmail.com>
2016-10-08 10:01:13 +01:00
Salah Triki
f7f675406b fs: befs: replace befs_bread by sb_bread
Since befs_bread merely calls sb_bread, replace it by sb_bread.

Link: http://lkml.kernel.org/r/1466800258-4542-1-git-send-email-salah.triki@gmail.com
Signed-off-by: Salah Triki <salah.triki@gmail.com>
Acked-by: Luis de Bethencourt <luisbg@osg.samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2016-10-08 10:01:12 +01:00
Luis de Bethencourt
f0f2536fe3 befs: remove unused functions
befs_iaddr_is_empty() and befs_brun_size() are unused. Remove them.

Link: http://lkml.kernel.org/r/1465700235-22881-3-git-send-email-luisbg@osg.samsung.com
Signed-off-by: Luis de Bethencourt <luisbg@osg.samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2016-10-08 10:01:12 +01:00
Luis de Bethencourt
10145d6116 befs: fix function name in documentation
Documentation of function befs_load_cb() lists it as load_befs_sb().  Fix
the misnomer.

Link: http://lkml.kernel.org/r/1465700235-22881-2-git-send-email-luisbg@osg.samsung.com
Signed-off-by: Luis de Bethencourt <luisbg@osg.samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2016-10-08 10:01:11 +01:00
Luis de Bethencourt
173b066f58 befs: check return of sb_min_blocksize
Confirm sb_min_blocksize() succeeded before continuing.

Link: http://lkml.kernel.org/r/1465700235-22881-1-git-send-email-luisbg@osg.samsung.com
Signed-off-by: Luis de Bethencourt <luisbg@osg.samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2016-10-08 10:01:10 +01:00
Salah Triki
c08f1cb627 fs: befs: remove useless pr_err in befs_init_inodecache()
Remove pr_err since kmem_cache_create log error and dump stack.

Link: http://lkml.kernel.org/r/e6d03cbc9542495dc6174b59e32fcd41c1393cfc.1464226521.git.salah.triki@acm.org
Signed-off-by: Salah Triki <salah.triki@acm.org>
2016-10-08 10:01:10 +01:00
Salah Triki
e808792784 fs/befs/linuxvfs.c: remove useless befs_error
Remove befs_error since when kmalloc fails there is a generic out of
memory and stack dump.

Link: http://lkml.kernel.org/r/3de4d388d98bbb570462a5eb8e64623e17fb5d74.1464226521.git.salah.triki@acm.org
Signed-off-by: Salah Triki <salah.triki@acm.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2016-10-08 10:01:10 +01:00
Salah Triki
c625426fb6 fs/befs/linuxvfs.c: remove useless pr_err in befs_fill_super()
Remove pr_err since when kzalloc fails there is a generic out of memory
and stack dump.

Link: http://lkml.kernel.org/r/c5a7f2d42ec0fc8465c118248e88cd221c483391.1464226521.git.salah.triki@acm.org
Signed-off-by: Salah Triki <salah.triki@acm.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2016-10-08 10:01:09 +01:00
Salah Triki
dceee2e230 fs/befs/linuxvfs.c: check silent flag before logging errors
Log errors only when silent flag is not set.

Link: http://lkml.kernel.org/r/d400aaf5a7430de79bd956e40ec075fb1cb08474.1464226521.git.salah.triki@acm.org
Signed-off-by: Salah Triki <salah.triki@acm.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2016-10-08 10:01:08 +01:00
Salah Triki
30982583e4 fs/befs/linuxvfs.c: move useless assignment
Control is transfered to unacquire_none when sb->s_fs_info is equal to
NULL, so the assignment to NULL is useless and it is moved above
unacquire_none.

Link: http://lkml.kernel.org/r/ed41da113fc693c7daa4e8813ca04cc766ddfc05.1464226521.git.salah.triki@acm.org
Signed-off-by: Salah Triki <salah.triki@acm.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2016-10-08 10:01:08 +01:00
Linus Torvalds
b66484cd74 Merge branch 'akpm' (patches from Andrew)
Merge updates from Andrew Morton:

 - fsnotify updates

 - ocfs2 updates

 - all of MM

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (127 commits)
  console: don't prefer first registered if DT specifies stdout-path
  cred: simpler, 1D supplementary groups
  CREDITS: update Pavel's information, add GPG key, remove snail mail address
  mailmap: add Johan Hovold
  .gitattributes: set git diff driver for C source code files
  uprobes: remove function declarations from arch/{mips,s390}
  spelling.txt: "modeled" is spelt correctly
  nmi_backtrace: generate one-line reports for idle cpus
  arch/tile: adopt the new nmi_backtrace framework
  nmi_backtrace: do a local dump_stack() instead of a self-NMI
  nmi_backtrace: add more trigger_*_cpu_backtrace() methods
  min/max: remove sparse warnings when they're nested
  Documentation/filesystems/proc.txt: add more description for maps/smaps
  mm, proc: fix region lost in /proc/self/smaps
  proc: fix timerslack_ns CAP_SYS_NICE check when adjusting self
  proc: add LSM hook checks to /proc/<tid>/timerslack_ns
  proc: relax /proc/<tid>/timerslack_ns capability requirements
  meminfo: break apart a very long seq_printf with #ifdefs
  seq/proc: modify seq_put_decimal_[u]ll to take a const char *, not char
  proc: faster /proc/*/status
  ...
2016-10-07 21:38:00 -07:00
Andreas Gruenbacher
fd50ecaddf vfs: Remove {get,set,remove}xattr inode operations
These inode operations are no longer used; remove them.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-10-07 21:48:36 -04:00
Alexey Dobriyan
81243eacfa cred: simpler, 1D supplementary groups
Current supplementary groups code can massively overallocate memory and
is implemented in a way so that access to individual gid is done via 2D
array.

If number of gids is <= 32, memory allocation is more or less tolerable
(140/148 bytes).  But if it is not, code allocates full page (!)
regardless and, what's even more fun, doesn't reuse small 32-entry
array.

2D array means dependent shifts, loads and LEAs without possibility to
optimize them (gid is never known at compile time).

All of the above is unnecessary.  Switch to the usual
trailing-zero-len-array scheme.  Memory is allocated with
kmalloc/vmalloc() and only as much as needed.  Accesses become simpler
(LEA 8(gi,idx,4) or even without displacement).

Maximum number of gids is 65536 which translates to 256KB+8 bytes.  I
think kernel can handle such allocation.

On my usual desktop system with whole 9 (nine) aux groups, struct
group_info shrinks from 148 bytes to 44 bytes, yay!

Nice side effects:

 - "gi->gid[i]" is shorter than "GROUP_AT(gi, i)", less typing,

 - fix little mess in net/ipv4/ping.c
   should have been using GROUP_AT macro but this point becomes moot,

 - aux group allocation is persistent and should be accounted as such.

Link: http://lkml.kernel.org/r/20160817201927.GA2096@p183.telecom.by
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Vasily Kulikov <segoon@openwall.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-07 18:46:30 -07:00
Robert Ho
855af072b6 mm, proc: fix region lost in /proc/self/smaps
Recently, Redhat reported that nvml test suite failed on QEMU/KVM,
more detailed info please refer to:

   https://bugzilla.redhat.com/show_bug.cgi?id=1365721

Actually, this bug is not only for NVDIMM/DAX but also for any other
file systems.  This simple test case abstracted from nvml can easily
reproduce this bug in common environment:

-------------------------- testcase.c -----------------------------

int
is_pmem_proc(const void *addr, size_t len)
{
        const char *caddr = addr;

        FILE *fp;
        if ((fp = fopen("/proc/self/smaps", "r")) == NULL) {
                printf("!/proc/self/smaps");
                return 0;
        }

        int retval = 0;         /* assume false until proven otherwise */
        char line[PROCMAXLEN];  /* for fgets() */
        char *lo = NULL;        /* beginning of current range in smaps file */
        char *hi = NULL;        /* end of current range in smaps file */
        int needmm = 0;         /* looking for mm flag for current range */
        while (fgets(line, PROCMAXLEN, fp) != NULL) {
                static const char vmflags[] = "VmFlags:";
                static const char mm[] = " wr";

                /* check for range line */
                if (sscanf(line, "%p-%p", &lo, &hi) == 2) {
                        if (needmm) {
                                /* last range matched, but no mm flag found */
                                printf("never found mm flag.\n");
                                break;
                        } else if (caddr < lo) {
                                /* never found the range for caddr */
                                printf("#######no match for addr %p.\n", caddr);
                                break;
                        } else if (caddr < hi) {
                                /* start address is in this range */
                                size_t rangelen = (size_t)(hi - caddr);

                                /* remember that matching has started */
                                needmm = 1;

                                /* calculate remaining range to search for */
                                if (len > rangelen) {
                                        len -= rangelen;
                                        caddr += rangelen;
                                        printf("matched %zu bytes in range "
                                                "%p-%p, %zu left over.\n",
                                                        rangelen, lo, hi, len);
                                } else {
                                        len = 0;
                                        printf("matched all bytes in range "
                                                        "%p-%p.\n", lo, hi);
                                }
                        }
                } else if (needmm && strncmp(line, vmflags,
                                        sizeof(vmflags) - 1) == 0) {
                        if (strstr(&line[sizeof(vmflags) - 1], mm) != NULL) {
                                printf("mm flag found.\n");
                                if (len == 0) {
                                        /* entire range matched */
                                        retval = 1;
                                        break;
                                }
                                needmm = 0;     /* saw what was needed */
                        } else {
                                /* mm flag not set for some or all of range */
                                printf("range has no mm flag.\n");
                                break;
                        }
                }
        }

        fclose(fp);

        printf("returning %d.\n", retval);
        return retval;
}

void *Addr;
size_t Size;

/*
 * worker -- the work each thread performs
 */
static void *
worker(void *arg)
{
        int *ret = (int *)arg;
        *ret =  is_pmem_proc(Addr, Size);
        return NULL;
}

int main(int argc, char *argv[])
{
        if (argc <  2 || argc > 3) {
                printf("usage: %s file [env].\n", argv[0]);
                return -1;
        }

        int fd = open(argv[1], O_RDWR);

        struct stat stbuf;
        fstat(fd, &stbuf);

        Size = stbuf.st_size;
        Addr = mmap(0, stbuf.st_size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);

        close(fd);

        pthread_t threads[NTHREAD];
        int ret[NTHREAD];

        /* kick off NTHREAD threads */
        for (int i = 0; i < NTHREAD; i++)
                pthread_create(&threads[i], NULL, worker, &ret[i]);

        /* wait for all the threads to complete */
        for (int i = 0; i < NTHREAD; i++)
                pthread_join(threads[i], NULL);

        /* verify that all the threads return the same value */
        for (int i = 1; i < NTHREAD; i++) {
                if (ret[0] != ret[i]) {
                        printf("Error i %d ret[0] = %d ret[i] = %d.\n", i,
                                ret[0], ret[i]);
                }
        }

        printf("%d", ret[0]);
        return 0;
}

It failed as some threads can not find the memory region in
"/proc/self/smaps" which is allocated in the main process

It is caused by proc fs which uses 'file->version' to indicate the VMA that
is the last one has already been handled by read() system call. When the
next read() issues, it uses the 'version' to find the VMA, then the next
VMA is what we want to handle, the related code is as follows:

        if (last_addr) {
                vma = find_vma(mm, last_addr);
                if (vma && (vma = m_next_vma(priv, vma)))
                        return vma;
        }

However, VMA will be lost if the last VMA is gone, e.g:

The process VMA list is A->B->C->D

CPU 0                                  CPU 1
read() system call
   handle VMA B
   version = B
return to userspace

                                   unmap VMA B

issue read() again to continue to get
the region info
   find_vma(version) will get VMA C
   m_next_vma(C) will get VMA D
   handle D
   !!! VMA C is lost !!!

In order to fix this bug, we make 'file->version' indicate the end address
of the current VMA.  m_start will then look up a vma which with vma_start
< last_vm_end and moves on to the next vma if we found the same or an
overlapping vma.  This will guarantee that we will not miss an exclusive
vma but we can still miss one if the previous vma was shrunk.  This is
acceptable because guaranteeing "never miss a vma" is simply not feasible.
User has to cope with some inconsistencies if the file is not read in one
go.

[mhocko@suse.com: changelog fixes]
Link: http://lkml.kernel.org/r/1475296958-27652-1-git-send-email-robert.hu@intel.com
Acked-by: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com>
Signed-off-by: Robert Hu <robert.hu@intel.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Stefan Hajnoczi <stefanha@redhat.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-07 18:46:30 -07:00
John Stultz
4b2bd5fec0 proc: fix timerslack_ns CAP_SYS_NICE check when adjusting self
In changing from checking ptrace_may_access(p, PTRACE_MODE_ATTACH_FSCREDS)
to capable(CAP_SYS_NICE), I missed that ptrace_my_access succeeds when p
== current, but the CAP_SYS_NICE doesn't.

Thus while the previous commit was intended to loosen the needed
privileges to modify a processes timerslack, it needlessly restricted a
task modifying its own timerslack via the proc/<tid>/timerslack_ns
(which is permitted also via the PR_SET_TIMERSLACK method).

This patch corrects this by checking if p == current before checking the
CAP_SYS_NICE value.

This patch applies on top of my two previous patches currently in -mm

Link: http://lkml.kernel.org/r/1471906870-28624-1-git-send-email-john.stultz@linaro.org
Signed-off-by: John Stultz <john.stultz@linaro.org>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Oren Laadan <orenl@cellrox.com>
Cc: Ruchi Kandoi <kandoiruchi@google.com>
Cc: Rom Lemarchand <romlem@android.com>
Cc: Todd Kjos <tkjos@google.com>
Cc: Colin Cross <ccross@android.com>
Cc: Nick Kralevich <nnk@google.com>
Cc: Dmitry Shmidt <dimitrysh@google.com>
Cc: Elliott Hughes <enh@google.com>
Cc: Android Kernel Team <kernel-team@android.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-07 18:46:30 -07:00
John Stultz
904763e1fb proc: add LSM hook checks to /proc/<tid>/timerslack_ns
As requested, this patch checks the existing LSM hooks
task_getscheduler/task_setscheduler when reading or modifying the task's
timerslack value.

Previous versions added new get/settimerslack LSM hooks, but since they
checked the same PROCESS__SET/GETSCHED values as existing hooks, it was
suggested we just use the existing ones.

Link: http://lkml.kernel.org/r/1469132667-17377-2-git-send-email-john.stultz@linaro.org
Signed-off-by: John Stultz <john.stultz@linaro.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Oren Laadan <orenl@cellrox.com>
Cc: Ruchi Kandoi <kandoiruchi@google.com>
Cc: Rom Lemarchand <romlem@android.com>
Cc: Todd Kjos <tkjos@google.com>
Cc: Colin Cross <ccross@android.com>
Cc: Nick Kralevich <nnk@google.com>
Cc: Dmitry Shmidt <dimitrysh@google.com>
Cc: Elliott Hughes <enh@google.com>
Cc: James Morris <jmorris@namei.org>
Cc: Android Kernel Team <kernel-team@android.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-07 18:46:30 -07:00
John Stultz
7abbaf9404 proc: relax /proc/<tid>/timerslack_ns capability requirements
When an interface to allow a task to change another tasks timerslack was
first proposed, it was suggested that something greater then
CAP_SYS_NICE would be needed, as a task could be delayed further then
what normally could be done with nice adjustments.

So CAP_SYS_PTRACE was adopted instead for what became the
/proc/<tid>/timerslack_ns interface.  However, for Android (where this
feature originates), giving the system_server CAP_SYS_PTRACE would allow
it to observe and modify all tasks memory.  This is considered too high
a privilege level for only needing to change the timerslack.

After some discussion, it was realized that a CAP_SYS_NICE process can
set a task as SCHED_FIFO, so they could fork some spinning processes and
set them all SCHED_FIFO 99, in effect delaying all other tasks for an
infinite amount of time.

So as a CAP_SYS_NICE task can already cause trouble for other tasks,
using it as a required capability for accessing and modifying
/proc/<tid>/timerslack_ns seems sufficient.

Thus, this patch loosens the capability requirements to CAP_SYS_NICE and
removes CAP_SYS_PTRACE, simplifying some of the code flow as well.

This is technically an ABI change, but as the feature just landed in
4.6, I suspect no one is yet using it.

Link: http://lkml.kernel.org/r/1469132667-17377-1-git-send-email-john.stultz@linaro.org
Signed-off-by: John Stultz <john.stultz@linaro.org>
Reviewed-by: Nick Kralevich <nnk@google.com>
Acked-by: Serge Hallyn <serge@hallyn.com>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Oren Laadan <orenl@cellrox.com>
Cc: Ruchi Kandoi <kandoiruchi@google.com>
Cc: Rom Lemarchand <romlem@android.com>
Cc: Todd Kjos <tkjos@google.com>
Cc: Colin Cross <ccross@android.com>
Cc: Nick Kralevich <nnk@google.com>
Cc: Dmitry Shmidt <dimitrysh@google.com>
Cc: Elliott Hughes <enh@google.com>
Cc: Android Kernel Team <kernel-team@android.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-07 18:46:30 -07:00
Joe Perches
e16e2d8e14 meminfo: break apart a very long seq_printf with #ifdefs
Use a specific routine to emit most lines so that the code is easier to
read and maintain.

akpm:
   text    data     bss     dec     hex filename
   2976       8       0    2984     ba8 fs/proc/meminfo.o before
   2669       8       0    2677     a75 fs/proc/meminfo.o after

Link: http://lkml.kernel.org/r/8fce7fdef2ba081a4ef531594e97da8a9feebb58.1470810406.git.joe@perches.com
Signed-off-by: Joe Perches <joe@perches.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-07 18:46:30 -07:00