From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753027AbbKWQW0 (ORCPT ); Mon, 23 Nov 2015 11:22:26 -0500 Received: from terminus.zytor.com ([198.137.202.10]:44416 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752499AbbKWQWE (ORCPT ); Mon, 23 Nov 2015 11:22:04 -0500 Date: Mon, 23 Nov 2015 08:21:29 -0800 From: tip-bot for Oleg Nesterov Message-ID: Cc: efault@gmx.de, peterz@infradead.org, tglx@linutronix.de, linux-kernel@vger.kernel.org, torvalds@linux-foundation.org, prarit@redhat.com, tj@kernel.org, hpa@zytor.com, milos@redhat.com, oleg@redhat.com, mingo@kernel.org Reply-To: oleg@redhat.com, milos@redhat.com, tj@kernel.org, hpa@zytor.com, mingo@kernel.org, tglx@linutronix.de, peterz@infradead.org, efault@gmx.de, linux-kernel@vger.kernel.org, torvalds@linux-foundation.org, prarit@redhat.com In-Reply-To: <20151115193311.GA8242@redhat.com> References: <20151115193311.GA8242@redhat.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:sched/core] stop_machine: Fix possible cpu_stopper_thread() crash Git-Commit-ID: 64038f292a1b33c7d46bd11f62f7798101152c00 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: 64038f292a1b33c7d46bd11f62f7798101152c00 Gitweb: http://git.kernel.org/tip/64038f292a1b33c7d46bd11f62f7798101152c00 Author: Oleg Nesterov AuthorDate: Sun, 15 Nov 2015 20:33:11 +0100 Committer: Ingo Molnar CommitDate: Mon, 23 Nov 2015 09:48:17 +0100 stop_machine: Fix possible cpu_stopper_thread() crash stop_one_cpu_nowait(fn) will crash the kernel if the callback returns nonzero, work->done == NULL in this case. This needs more cleanups, cpu_stop_signal_done() is called right after we check done != NULL and it does the same check. Signed-off-by: Oleg Nesterov Signed-off-by: Peter Zijlstra (Intel) Acked-by: Tejun Heo Cc: Linus Torvalds Cc: Mike Galbraith Cc: Milos Vyletel Cc: Peter Zijlstra Cc: Prarit Bhargava Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/20151115193311.GA8242@redhat.com Signed-off-by: Ingo Molnar --- kernel/stop_machine.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/stop_machine.c b/kernel/stop_machine.c index 867bc20..1a66a95 100644 --- a/kernel/stop_machine.c +++ b/kernel/stop_machine.c @@ -454,7 +454,7 @@ repeat: preempt_disable(); ret = fn(arg); - if (ret) + if (ret && done) done->ret = ret; /* restore preemption and check it's still balanced */