From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:53369 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932446AbcBXEOy (ORCPT ); Tue, 23 Feb 2016 23:14:54 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Thomas Gleixner , Peter Zijlstra , Darren Hart , Davidlohr Bueso , Bhuvanesh_Surachari@mentor.com, Andy Lowe Subject: [PATCH 4.4 122/137] futex: Drop refcount if requeue_pi() acquired the rtmutex Date: Tue, 23 Feb 2016 19:34:13 -0800 Message-Id: <20160224033421.255688496@linuxfoundation.org> In-Reply-To: <20160224033417.270530882@linuxfoundation.org> References: <20160224033417.270530882@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Thomas Gleixner 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 Cc: Peter Zijlstra Cc: Darren Hart Cc: Davidlohr Bueso Cc: Bhuvanesh_Surachari@mentor.com Cc: Andy Lowe Link: http://lkml.kernel.org/r/20151219200607.178132067@linutronix.de Signed-off-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman --- kernel/futex.c | 5 +++++ 1 file changed, 5 insertions(+) --- a/kernel/futex.c +++ b/kernel/futex.c @@ -2755,6 +2755,11 @@ static int futex_wait_requeue_pi(u32 __u 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 {