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>
This commit is contained in:
Adrian Hunter 2015-08-19 17:29:19 +03:00 committed by Arnaldo Carvalho de Melo
parent d7a702f0b1
commit 0d7e7acc47

View file

@ -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)