[PATCH 3.16.y-ckt 120/216] exit: pidns: alloc_pid() leaks pid_namespace if child_reaper is exiting

Luis Henriques
2015-01-12T19:04:47Z

From: Oleg Nesterov <oleg@redhat.com>

commit 24c037ebf5723d4d9ab0996433cee4f96c292a4d upstream.

alloc_pid() does get_pid_ns() beforehand but forgets to put_pid_ns() if it
fails because disable_pid_allocation() was called by the exiting
child_reaper.

We could simply move get_pid_ns() down to successful return, but this fix
tries to be as trivial as possible.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Aaron Tomlin <atomlin@redhat.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Serge Hallyn <serge.hallyn@ubuntu.com>
Cc: Sterling Alexander <stalexan@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
---
kernel/pid.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/kernel/pid.c b/kernel/pid.c
index 9b9a26698144..82430c858d69 100644
--- a/kernel/pid.c
+++ b/kernel/pid.c
@@ -341,6 +341,8 @@ out:

out_unlock:
spin_unlock_irq(&pidmap_lock);
+ put_pid_ns(ns);
+
out_free:
while (++i <= ns->level)
free_pidmap(pid->numbers + i);
--
2.1.4