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authorThomas Gleixner <tglx@linutronix.de>2015-12-19 20:07:38 +0000
committerJiri Slaby <jslaby@suse.cz>2016-02-25 10:49:18 +0100
commit8a39ca32bd3910e1df5824769bacb9b7af3d83b9 (patch)
parent5e903959740934e0fe34a01ce5b5511cf501d4c6 (diff)
futex: Drop refcount if requeue_pi() acquired the rtmutex
commit fb75a4282d0d9a3c7c44d940582c2d226cf3acfb upstream. If the proxy lock in the requeue loop acquires the rtmutex for a waiter then it acquired also refcount on the pi_state related to the futex, but the waiter side does not drop the reference count. Add the missing free_pi_state() call. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Darren Hart <darren@dvhart.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Bhuvanesh_Surachari@mentor.com Cc: Andy Lowe <Andy_Lowe@mentor.com> Link: http://lkml.kernel.org/r/20151219200607.178132067@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
1 files changed, 5 insertions, 0 deletions
diff --git a/kernel/futex.c b/kernel/futex.c
index 3ee1b3ce78df..509bdd404414 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -2497,6 +2497,11 @@ static int futex_wait_requeue_pi(u32 __user *uaddr, unsigned int flags,
if (q.pi_state && (q.pi_state->owner != current)) {
ret = fixup_pi_state_owner(uaddr2, &q, current);
+ /*
+ * Drop the reference to the pi state which
+ * the requeue_pi() code acquired for us.
+ */
+ free_pi_state(q.pi_state);
} else {