Commit 0d7e7acc authored Aug 19, 2015 by Adrian Hunter Committed by Arnaldo Carvalho de Melo Aug 19, 2015

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 <torvalds@linux-foundation.org>
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Tested-by: Jiri Olsa <jolsa@kernel.org>
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 <acme@redhat.com>

parent d7a702f0

tools/perf/util/thread.c

+6 −0

Original line number	Diff line number	Diff line
		@@ -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)

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