Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751607AbaGPT2b (ORCPT ); Wed, 16 Jul 2014 15:28:31 -0400 Received: from terminus.zytor.com ([198.137.202.10]:44472 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965777AbaGPTXC (ORCPT ); Wed, 16 Jul 2014 15:23:02 -0400 Date: Wed, 16 Jul 2014 12:22:10 -0700 From: tip-bot for Mateusz Guzik Message-ID: Cc: linux-kernel@vger.kernel.org, hpa@zytor.com, mingo@kernel.org, torvalds@linux-foundation.org, peterz@infradead.org, mguzik@redhat.com, tglx@linutronix.de Reply-To: mingo@kernel.org, hpa@zytor.com, linux-kernel@vger.kernel.org, torvalds@linux-foundation.org, peterz@infradead.org, tglx@linutronix.de, mguzik@redhat.com In-Reply-To: <1402750809-31991-1-git-send-email-mguzik@redhat.com> References: <1402750809-31991-1-git-send-email-mguzik@redhat.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:sched/urgent] sched: Fix possible divide by zero in avg_atom () calculation Git-Commit-ID: b0ab99e7736af88b8ac1b7ae50ea287fffa2badc 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: b0ab99e7736af88b8ac1b7ae50ea287fffa2badc Gitweb: http://git.kernel.org/tip/b0ab99e7736af88b8ac1b7ae50ea287fffa2badc Author: Mateusz Guzik AuthorDate: Sat, 14 Jun 2014 15:00:09 +0200 Committer: Ingo Molnar CommitDate: Wed, 16 Jul 2014 13:36:07 +0200 sched: Fix possible divide by zero in avg_atom() calculation proc_sched_show_task() does: if (nr_switches) do_div(avg_atom, nr_switches); nr_switches is unsigned long and do_div truncates it to 32 bits, which means it can test non-zero on e.g. x86-64 and be truncated to zero for division. Fix the problem by using div64_ul() instead. As a side effect calculations of avg_atom for big nr_switches are now correct. Signed-off-by: Mateusz Guzik Signed-off-by: Peter Zijlstra Cc: stable@vger.kernel.org Cc: Linus Torvalds Link: http://lkml.kernel.org/r/1402750809-31991-1-git-send-email-mguzik@redhat.com Signed-off-by: Ingo Molnar --- kernel/sched/debug.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c index 695f977..627b3c3 100644 --- a/kernel/sched/debug.c +++ b/kernel/sched/debug.c @@ -608,7 +608,7 @@ void proc_sched_show_task(struct task_struct *p, struct seq_file *m) avg_atom = p->se.sum_exec_runtime; if (nr_switches) - do_div(avg_atom, nr_switches); + avg_atom = div64_ul(avg_atom, nr_switches); else avg_atom = -1LL; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/