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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/sem.c | |
| parent | bac7a1fff7926fb9891a18fe33650884b0e13e41 (diff) | |
| download | linux-87ad4b0d853e8a65d6002f4e7bd3dce4ae3a52da.tar.bz2 | |
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/sem.c')
| -rw-r--r-- | ipc/sem.c | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/ipc/sem.c b/ipc/sem.c index 87bd38f38dc3..a4af04979fd2 100644 --- a/ipc/sem.c +++ b/ipc/sem.c @@ -1213,10 +1213,20 @@ static int semctl_stat(struct ipc_namespace *ns, int semid, if (err) goto out_unlock; + ipc_lock_object(&sma->sem_perm); + + if (!ipc_valid_object(&sma->sem_perm)) { + ipc_unlock_object(&sma->sem_perm); + err = -EIDRM; + goto out_unlock; + } + kernel_to_ipc64_perm(&sma->sem_perm, &semid64->sem_perm); semid64->sem_otime = get_semotime(sma); semid64->sem_ctime = sma->sem_ctime; semid64->sem_nsems = sma->sem_nsems; + + ipc_unlock_object(&sma->sem_perm); rcu_read_unlock(); return id; |