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| author |   Philippe Mikoyan <philippe.mikoyan@skat.systems> | 2018-02-06 15:40:49 -0800 |
|---|---|---|
| committer |   Linus Torvalds <torvalds@linux-foundation.org> | 2018-02-06 18:32:46 -0800 |
| commit | 87ad4b0d853e8a65d6002f4e7bd3dce4ae3a52da (patch) | |
| tree | c1e7faec69a13a77606fd6e8c9578080ffe531e1 /ipc/util.c | |
| parent | lib/ubsan: remove returns-nonnull-attribute checks (diff) | |
| download | linux-dev-87ad4b0d853e8a65d6002f4e7bd3dce4ae3a52da.tar.xz linux-dev-87ad4b0d853e8a65d6002f4e7bd3dce4ae3a52da.zip | |
ipc: fix ipc data structures inconsistency
As described in the title, this patch fixes <ipc>id_ds inconsistency when
<ipc>ctl_stat executes concurrently with some ds-changing function, e.g.
shmat, msgsnd or whatever.
For instance, if shmctl(IPC_STAT) is running concurrently
with shmat, following data structure can be returned:
{... shm_lpid = 0, shm_nattch = 1, ...}
Link: http://lkml.kernel.org/r/20171202153456.6514-1-philippe.mikoyan@skat.systems
Signed-off-by: Philippe Mikoyan <philippe.mikoyan@skat.systems>
Reviewed-by: Davidlohr Bueso <dbueso@suse.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'ipc/util.c')
| -rw-r--r-- | ipc/util.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/ipc/util.c b/ipc/util.c index ff045fec8d83..4ed5a17dd06f 100644 --- a/ipc/util.c +++ b/ipc/util.c @@ -23,9 +23,12 @@ * tree. * - perform initial checks (capabilities, auditing and permission, * etc). - * - perform read-only operations, such as STAT, INFO commands. + * - perform read-only operations, such as INFO command, that + * do not demand atomicity * acquire the ipc lock (kern_ipc_perm.lock) through * ipc_lock_object() + * - perform read-only operations that demand atomicity, + * such as STAT command. * - perform data updates, such as SET, RMID commands and * mechanism-specific operations (semop/semtimedop, * msgsnd/msgrcv, shmat/shmdt). |