path: root/ipc/util.c
diff options
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/util.c
parentlib/ubsan: remove returns-nonnull-attribute checks (diff)
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')
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).