From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932156AbcBXRy6 (ORCPT ); Wed, 24 Feb 2016 12:54:58 -0500 Received: from casper.infradead.org ([85.118.1.10]:35817 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754671AbcBXRwy (ORCPT ); Wed, 24 Feb 2016 12:52:54 -0500 Message-Id: <20160224174948.159242158@infradead.org> User-Agent: quilt/0.61-1 Date: Wed, 24 Feb 2016 18:45:48 +0100 From: Peter Zijlstra To: peterz@infradead.org, mingo@kernel.org, alexander.shishkin@linux.intel.com, eranian@google.com Cc: linux-kernel@vger.kernel.org, vince@deater.net, dvyukov@google.com, andi@firstfloor.org, jolsa@redhat.com, panand@redhat.com, sasha.levin@oracle.com, oleg@redhat.com Subject: [PATCH 09/12] perf: Fix scaling vs enable_on_exec References: <20160224174539.570749654@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline; filename=peterz-perf-more-fixes-11.patch Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The recent commit 3e349507d12d ("perf: Fix perf_enable_on_exec() event scheduling") caused this by moving task_ctx_sched_out() from before __perf_event_mask_enable() to after it. The overlooked concequence of that change is that task_ctx_sched_out() would update the ctx time fields, and now __perf_event_mask_enable() uses stale time. In order to fix this, explicitly stop our context's time before enabling the event(s). Fixes: 3e349507d12d ("perf: Fix perf_enable_on_exec() event scheduling") Reported-by: Oleg Nesterov Signed-off-by: Peter Zijlstra (Intel) --- kernel/events/core.c | 1 + 1 file changed, 1 insertion(+) --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -3143,6 +3143,7 @@ static void perf_event_enable_on_exec(in cpuctx = __get_cpu_context(ctx); perf_ctx_lock(cpuctx, ctx); + ctx_sched_out(ctx, cpuctx, EVENT_TIME); list_for_each_entry(event, &ctx->event_list, event_entry) enabled |= event_enable_on_exec(event, ctx);