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authorAdrian Hunter <adrian.hunter@intel.com>2015-08-19 16:29:19 +0200
committerArnaldo Carvalho de Melo <acme@redhat.com>2015-08-19 19:15:09 +0200
commit0d7e7acc47133e82911e24758178815cfee309e9 (patch)
treec95e7817da85ba9a8bf711d58600add03b7a16df /tools/perf/util/thread.c
parentperf/x86/intel/cqm: Do not access cpu_data() from CPU_UP_PREPARE handler (diff)
downloadlinux-0d7e7acc47133e82911e24758178815cfee309e9.tar.xz
linux-0d7e7acc47133e82911e24758178815cfee309e9.zip
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>
Diffstat (limited to 'tools/perf/util/thread.c')
-rw-r--r--tools/perf/util/thread.c6
1 files changed, 6 insertions, 0 deletions
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)