[PATCH] simplify audit_free() locking

Simplify audit_free()'s locking: no need to lock a task that we are tearing
down.  [the extra locking also caused false positives in the lock
validator]

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Cc: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 7 insertions, 3 deletions

diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index d3d499272d13..b613ec89e99c 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -704,10 +704,14 @@ void audit_free(struct task_struct *tsk)
 {
         struct audit_context *context;
 
-        task_lock(tsk);
+        /*
+         * No need to lock the task - when we execute audit_free()
+         * then the task has no external references anymore, and
+         * we are tearing it down. (The locking also confuses
+         * DEBUG_LOCKDEP - this freeing may occur in softirq
+         * contexts as well, via RCU.)
+         */
         context = audit_get_context(tsk, 0, 0);
-        task_unlock(tsk);
-
         if (likely(!context))
                 return;