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authorOleg Nesterov <oleg@redhat.com>2014-04-02 17:45:05 +0200
committerJiri Slaby <jslaby@suse.cz>2014-05-05 14:24:38 +0200
commitd2bba52561f3ea43a0323cd33687b068a69dd8cc (patch)
tree498a2d61a06dba258c9dbeca017fd7babb074ec4
parent18b258a37ee54cab6d0fc33f70b3c9d0ecf2dfdb (diff)
pid_namespace: pidns_get() should check task_active_pid_ns() != NULL
commit d23082257d83e4bc89727d5aedee197e907999d2 upstream. 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> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
-rw-r--r--kernel/pid_namespace.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/kernel/pid_namespace.c b/kernel/pid_namespace.c
index 42086551a24a..55e956056987 100644
--- a/kernel/pid_namespace.c
+++ b/kernel/pid_namespace.c
@@ -312,7 +312,9 @@ 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;