Path: csiph.com!news.mixmin.net!newsreader4.netcologne.de!news.netcologne.de!newsfeed.kamp.net!newsfeed.kamp.net!fu-berlin.de!bofh.it!news.nic.it!robomod From: Adrian Hunter Newsgroups: linux.kernel Subject: [PATCH 1/3] perf tools: Avoid deadlock when map_groups are broken Date: Wed, 19 Aug 2015 16:40:01 +0200 Message-ID: References: X-Original-To: Arnaldo Carvalho de Melo , Arnaldo Carvalho de Melo , Jiri Olsa , Jiri Olsa X-Extloop1: 1 X-Ironport-Av: E=Sophos;i="5.15,710,1432623600"; d="scan'208";a="544778923" X-Mailer: git-send-email 1.9.1 Organization: Intel Finland Oy, Registered Address: PL 281, 00181 Helsinki, Business Identity Code: 0357606 - 4, Domiciled in Helsinki Sender: robomod@news.nic.it List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Approved: robomod@news.nic.it Lines: 34 X-Original-Cc: linux-kernel@vger.kernel.org, torvalds@linux-foundation.org, mingo@kernel.org X-Original-Date: Wed, 19 Aug 2015 17:29:19 +0300 X-Original-Message-ID: <1439994561-27436-2-git-send-email-adrian.hunter@intel.com> X-Original-References: <1439994561-27436-1-git-send-email-adrian.hunter@intel.com> X-Original-Sender: linux-kernel-owner@vger.kernel.org Xref: csiph.com linux.kernel:1209851 Attempting to clone map groups onto themselves will deadlock. It only happens because of other bugs, but the code should protect itself anyway. Signed-off-by: Adrian Hunter --- 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 28c4b746baa1..471102554a78 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) { + dump_printf("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) -- 1.9.1 -- 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/