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authorPhilippe Mikoyan <philippe.mikoyan@skat.systems>2018-02-06 15:40:49 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2018-02-06 18:32:46 -0800
commit87ad4b0d853e8a65d6002f4e7bd3dce4ae3a52da (patch)
treec1e7faec69a13a77606fd6e8c9578080ffe531e1 /ipc/sem.c
parentlib/ubsan: remove returns-nonnull-attribute checks (diff)
downloadlinux-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/sem.c')
-rw-r--r--ipc/sem.c10
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;