ipc: use rlimit helpers

Make sure compiler won't do weird things with limits.  E.g.  fetching them
twice may return 2 different values after writable limits are implemented.

I.e.  either use rlimit helpers added in
3e10e716abf3c71bdb5d86b8f507f9e72236c9cd ("resource: add helpers for
fetching rlimits") or ACCESS_ONCE if not applicable.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 1 insertions, 2 deletions

diff --git a/ipc/shm.c b/ipc/shm.c
index 23256b855819..1a314c89f93c 100644
--- a/ipc/shm.c
+++ b/ipc/shm.c
@@ -764,8 +764,7 @@ SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf)
                         if (euid != shp->shm_perm.uid &&
                             euid != shp->shm_perm.cuid)
                                 goto out_unlock;
-                        if (cmd == SHM_LOCK &&
-                            !current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur)
+                        if (cmd == SHM_LOCK && !rlimit(RLIMIT_MEMLOCK))
                                 goto out_unlock;
                 }