From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752803AbbHTKAI (ORCPT ); Thu, 20 Aug 2015 06:00:08 -0400 Received: from terminus.zytor.com ([198.137.202.10]:35187 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751524AbbHTKAA (ORCPT ); Thu, 20 Aug 2015 06:00:00 -0400 Date: Thu, 20 Aug 2015 02:59:48 -0700 From: tip-bot for Adrian Hunter Message-ID: Cc: linux-kernel@vger.kernel.org, torvalds@linux-foundation.org, adrian.hunter@intel.com, hpa@zytor.com, acme@redhat.com, jolsa@kernel.org, tglx@linutronix.de, mingo@kernel.org Reply-To: torvalds@linux-foundation.org, adrian.hunter@intel.com, hpa@zytor.com, acme@redhat.com, jolsa@kernel.org, tglx@linutronix.de, mingo@kernel.org, linux-kernel@vger.kernel.org In-Reply-To: <1439994561-27436-2-git-send-email-adrian.hunter@intel.com> References: <1439994561-27436-2-git-send-email-adrian.hunter@intel.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:perf/core] perf tools: Avoid deadlock when map_groups are broken Git-Commit-ID: 0d7e7acc47133e82911e24758178815cfee309e9 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: 0d7e7acc47133e82911e24758178815cfee309e9 Gitweb: http://git.kernel.org/tip/0d7e7acc47133e82911e24758178815cfee309e9 Author: Adrian Hunter AuthorDate: Wed, 19 Aug 2015 17:29:19 +0300 Committer: Arnaldo Carvalho de Melo CommitDate: Wed, 19 Aug 2015 14:15:09 -0300 perf tools: Avoid deadlock when map_groups are broken Attempting to clone map groups onto themselves will deadlock. It only happens because of other bugs, but the code should protect itself anyway. Reported-by: Linus Torvalds Signed-off-by: Adrian Hunter Tested-by: Jiri Olsa Link: http://lkml.kernel.org/r/1439994561-27436-2-git-send-email-adrian.hunter@intel.com [ Use pr_debug() instead of dump_fprintf() ] Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/thread.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/tools/perf/util/thread.c b/tools/perf/util/thread.c index 28c4b74..0a9ae80 100644 --- a/tools/perf/util/thread.c +++ b/tools/perf/util/thread.c @@ -191,6 +191,12 @@ static int thread__clone_map_groups(struct thread *thread, if (thread->pid_ == parent->pid_) return 0; + if (thread->mg == parent->mg) { + pr_debug("broken map groups on thread %d/%d parent %d/%d\n", + thread->pid_, thread->tid, parent->pid_, parent->tid); + return 0; + } + /* But this one is new process, copy maps. */ for (i = 0; i < MAP__NR_TYPES; ++i) if (map_groups__clone(thread->mg, parent->mg, i) < 0)