pid_namespace: pidns_get() should check task_active_pid_ns() != NULL

pidns_get()->get_pid_ns() can hit ns == NULL. This task_struct can't
go away, but task_active_pid_ns(task) is NULL if release_task(task)
was already called. Alternatively we could change get_pid_ns(ns) to
check ns != NULL, but it seems that other callers are fine.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Eric W. Biederman ebiederm@xmission.com>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Oleg Nesterov 2014-04-02 17:45:05 +02:00 committed by Linus Torvalds
parent 7cbb39d4d4
commit d23082257d
1 changed files with 3 additions and 1 deletions

View File

@ -318,7 +318,9 @@ static void *pidns_get(struct task_struct *task)
struct pid_namespace *ns;
rcu_read_lock();
ns = get_pid_ns(task_active_pid_ns(task));
ns = task_active_pid_ns(task);
if (ns)
get_pid_ns(ns);
rcu_read_unlock();
return ns;