tree 74174553e2729fd582dc73f9d61b2a54286b3ede
parent 6c6e3b828b2a13b923b9465fc4316c5bdc92291f
author Vasiliy Kulikov <segoon@openwall.com> 1311897331 +0400
committer Linus Torvalds <torvalds@linux-foundation.org> 1312051459 -1000

shm: handle separate PID namespaces case

shm_try_destroy_orphaned() and shm_try_destroy_current() didn't handle
the case of separate PID namespaces, but a single IPC namespace.  If
there are tasks with the same PID values using the same shmem object,
the wrong destroy decision could be reached.

On shm segment creation store the pointer to the creator task in
shmid_kernel->shm_creator field and zero it on task exit.  Then
use the ->shm_creator insread of shm_cprid in both functions.  As
shmid_kernel object is already locked at this stage, no additional
locking is needed.

Signed-off-by: Vasiliy Kulikov <segoon@openwall.com>
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>