[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>

diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index d3d4992..b613ec8 100644 (file)
--- 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;