Avoid race in single thread suspension.
Don't allow more than one concurrent single thread suspension to avoid
potential cycles and deadlocks where threads try to suspend each other.
Bug: 16364458, 16354227
Change-Id: I907f1d5591a6aa5c241d37d6b4a34f968f98df77
diff --git a/runtime/monitor.cc b/runtime/monitor.cc
index 4b26eda..b33b286 100644
--- a/runtime/monitor.cc
+++ b/runtime/monitor.cc
@@ -680,6 +680,8 @@
Thread* owner;
{
ScopedThreadStateChange tsc(self, kBlocked);
+ // Take suspend thread lock to avoid races with threads trying to suspend this one.
+ MutexLock mu(self, *Locks::thread_list_suspend_thread_lock_);
owner = thread_list->SuspendThreadByThreadId(owner_thread_id, false, &timed_out);
}
if (owner != nullptr) {