[sanitizer] Fix deadlock in StopTheWorld.
The tracer thread in StopTheWorld could wait on a mutex forever if the parent
process died before unlocking it. Use PR_SET_PDEATHSIG so that the parent would
kill the child in this scenario.
llvm-svn: 192210
diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_stoptheworld_linux_libcdep.cc b/compiler-rt/lib/sanitizer_common/sanitizer_stoptheworld_linux_libcdep.cc
index 3c650be..d632053 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_stoptheworld_linux_libcdep.cc
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_stoptheworld_linux_libcdep.cc
@@ -224,6 +224,11 @@
TracerThreadArgument *tracer_thread_argument =
(TracerThreadArgument *)argument;
+ internal_prctl(PR_SET_PDEATHSIG, SIGKILL, 0, 0, 0);
+ // Check if parent is already dead.
+ if (internal_getppid() == 1)
+ internal__exit(4);
+
// Wait for the parent thread to finish preparations.
tracer_thread_argument->mutex.Lock();
tracer_thread_argument->mutex.Unlock();
