Messages in this thread Patch in this message |  | | Date | Sun, 20 Dec 2015 05:18:39 -0800 | From | tip-bot for Thomas Gleixner <> | Subject | [tip:locking/core] futex: Drop refcount if requeue_pi() acquired the rtmutex |
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Commit-ID: fb75a4282d0d9a3c7c44d940582c2d226cf3acfb Gitweb: http://git.kernel.org/tip/fb75a4282d0d9a3c7c44d940582c2d226cf3acfb Author: Thomas Gleixner <tglx@linutronix.de> AuthorDate: Sat, 19 Dec 2015 20:07:38 +0000 Committer: Thomas Gleixner <tglx@linutronix.de> CommitDate: Sun, 20 Dec 2015 12:43:24 +0100
futex: Drop refcount if requeue_pi() acquired the rtmutex
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> Cc: stable@vger.kernel.org --- kernel/futex.c | 5 +++++ 1 file changed, 5 insertions(+)
diff --git a/kernel/futex.c b/kernel/futex.c index 684d754..24fbc77 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -2755,6 +2755,11 @@ static int futex_wait_requeue_pi(u32 __user *uaddr, unsigned int flags, if (q.pi_state && (q.pi_state->owner != current)) { spin_lock(q.lock_ptr); 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); spin_unlock(q.lock_ptr); } } else {
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