From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934711AbbI2KeF (ORCPT ); Tue, 29 Sep 2015 06:34:05 -0400 Received: from terminus.zytor.com ([198.137.202.10]:39354 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934550AbbI2Kdv (ORCPT ); Tue, 29 Sep 2015 06:33:51 -0400 Date: Tue, 29 Sep 2015 03:31:16 -0700 From: tip-bot for Peter Zijlstra Message-ID: Cc: torvalds@linux-foundation.org, mingo@kernel.org, efault@gmx.de, linux-kernel@vger.kernel.org, peterz@infradead.org, hpa@zytor.com, tglx@linutronix.de Reply-To: torvalds@linux-foundation.org, mingo@kernel.org, peterz@infradead.org, tglx@linutronix.de, hpa@zytor.com, efault@gmx.de, linux-kernel@vger.kernel.org In-Reply-To: <20150929093519.930244771@infradead.org> References: <20150929093519.930244771@infradead.org> To: linux-tip-commits@vger.kernel.org Subject: [tip:sched/core] sched/core: Robustify preemption leak checks Git-Commit-ID: 185b42420b0948dfc00af6cc5d93aa00b7fef581 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 185b42420b0948dfc00af6cc5d93aa00b7fef581 Gitweb: http://git.kernel.org/tip/185b42420b0948dfc00af6cc5d93aa00b7fef581 Author: Peter Zijlstra AuthorDate: Tue, 29 Sep 2015 11:28:28 +0200 Committer: Ingo Molnar CommitDate: Tue, 29 Sep 2015 12:27:40 +0200 sched/core: Robustify preemption leak checks When we warn about a preempt_count leak; reset the preempt_count to the known good value such that the problem does not ripple forward. Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Mike Galbraith Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: fweisbec@gmail.com Cc: linux-kernel@vger.kernel.org Cc: oleg@redhat.com Cc: rostedt@goodmis.org Cc: umgwanakikbuti@gmail.com Link: http://lkml.kernel.org/r/20150929093519.930244771@infradead.org Signed-off-by: Ingo Molnar --- kernel/exit.c | 4 +++- kernel/sched/core.c | 4 +++- 2 files changed, 6 insertions(+), 2 deletions(-) diff --git a/kernel/exit.c b/kernel/exit.c index ea95ee1..443677c 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -706,10 +706,12 @@ void do_exit(long code) smp_mb(); raw_spin_unlock_wait(&tsk->pi_lock); - if (unlikely(in_atomic())) + if (unlikely(in_atomic())) { pr_info("note: %s[%d] exited with preempt_count %d\n", current->comm, task_pid_nr(current), preempt_count()); + preempt_count_set(PREEMPT_ENABLED); + } /* sync mm's RSS info before statistics gathering */ if (tsk->mm) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index ecd585c..d1dec5d 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -2953,8 +2953,10 @@ static inline void schedule_debug(struct task_struct *prev) * schedule() atomically, we ignore that path. Otherwise whine * if we are scheduling when we should not. */ - if (unlikely(in_atomic_preempt_off() && prev->state != TASK_DEAD)) + if (unlikely(in_atomic_preempt_off() && prev->state != TASK_DEAD)) { __schedule_bug(prev); + preempt_count_set(PREEMPT_DISABLED); + } rcu_sleep_check(); profile_hit(SCHED_PROFILING, __builtin_return_address(0));