From mboxrd@z Thu Jan 1 00:00:00 1970 From: Darren Hart Subject: [PATCH 1/4] rtmutex: avoid null derefence in WARN_ON Date: Fri, 9 Jul 2010 15:32:57 -0700 Message-ID: <1278714780-788-2-git-send-email-dvhltc@us.ibm.com> References: <1278714780-788-1-git-send-email-dvhltc@us.ibm.com> Cc: Thomas Gleixner , Peter Zijlstra , Ingo Molnar , Eric Dumazet , John Kacur , Steven Rostedt , Mike Galbraith , linux-rt-users@vger.kernel.org, Darren Hart To: linux-kernel@vger.kernel.org Return-path: Received: from e38.co.us.ibm.com ([32.97.110.159]:53879 "EHLO e38.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755297Ab0GIWd2 (ORCPT ); Fri, 9 Jul 2010 18:33:28 -0400 In-Reply-To: <1278714780-788-1-git-send-email-dvhltc@us.ibm.com> Sender: linux-rt-users-owner@vger.kernel.org List-ID: If the pi_blocked_on variable is NULL, the subsequent WARN_ON's will cause an OOPS. Only perform the susequent checks if pi_blocked_on is valid. Signed-off-by: Darren Hart Cc: Thomas Gleixner Cc: Peter Zijlstra Cc: Ingo Molnar Cc: Eric Dumazet Cc: John Kacur Cc: Steven Rostedt Cc: Mike Galbraith --- kernel/rtmutex.c | 7 ++++--- 1 files changed, 4 insertions(+), 3 deletions(-) diff --git a/kernel/rtmutex.c b/kernel/rtmutex.c index 23dd443..baac7d9 100644 --- a/kernel/rtmutex.c +++ b/kernel/rtmutex.c @@ -579,9 +579,10 @@ static void wakeup_next_waiter(struct rt_mutex *lock, int savestate) raw_spin_lock(&pendowner->pi_lock); - WARN_ON(!pendowner->pi_blocked_on); - WARN_ON(pendowner->pi_blocked_on != waiter); - WARN_ON(pendowner->pi_blocked_on->lock != lock); + if (!WARN_ON(!pendowner->pi_blocked_on)) { + WARN_ON(pendowner->pi_blocked_on != waiter); + WARN_ON(pendowner->pi_blocked_on->lock != lock); + } pendowner->pi_blocked_on = NULL; -- 1.7.0.4