From 0d7e7acc47133e82911e24758178815cfee309e9 Mon Sep 17 00:00:00 2001 From: Adrian Hunter Date: Wed, 19 Aug 2015 17:29:19 +0300 Subject: [PATCH] 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 28c4b746baa1..0a9ae8014729 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)