From mboxrd@z Thu Jan 1 00:00:00 1970 From: Steven Rostedt Subject: [PATCH RT 17/39] rtmutex.c: Fix incorrect waiter check Date: Thu, 12 Mar 2015 15:13:24 -0400 Message-ID: <20150312191409.880520048@goodmis.org> References: <20150312191307.081068717@goodmis.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Cc: Thomas Gleixner , Carsten Emde , Sebastian Andrzej Siewior , John Kacur , Paul Gortmaker , Brad Mouring , Ben Shelton , T Makphaibulchoke , To: linux-kernel@vger.kernel.org, linux-rt-users Return-path: Received: from cdptpa-outbound-snat.email.rr.com ([107.14.166.226]:54317 "EHLO cdptpa-oedge-vip.email.rr.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1755343AbbCLTP1 (ORCPT ); Thu, 12 Mar 2015 15:15:27 -0400 Content-Disposition: inline; filename=0017-rtmutex.c-Fix-incorrect-waiter-check.patch Sender: linux-rt-users-owner@vger.kernel.org List-ID: 3.14.34-rt32-rc1 stable review patch. If anyone has any objections, please let me know. ------------------ From: Brad Mouring In task_blocks_on_lock, there's a null check on pi_blocked_on of the task_struct. This pointer can encode the fact that the task that contains the pointer is waking (preventing requeuing) and therefore is non-null. Use the inline function to avoid dereferencing an invalid "pointer" Signed-off-by: Brad Mouring Reported-by: Ben Shelton Reviewed-by: T Makphaibulchoke Tested-by: T Makphaibulchoke Cc: stable-rt@vger.kernel.org Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Steven Rostedt --- kernel/locking/rtmutex.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c index ec72272ab73a..74a824523d3a 100644 --- a/kernel/locking/rtmutex.c +++ b/kernel/locking/rtmutex.c @@ -361,7 +361,8 @@ int max_lock_depth = 1024; static inline struct rt_mutex *task_blocked_on_lock(struct task_struct *p) { - return p->pi_blocked_on ? p->pi_blocked_on->lock : NULL; + return rt_mutex_real_waiter(p->pi_blocked_on) ? + p->pi_blocked_on->lock : NULL; } /* -- 2.1.4