From 2dec3d7021fca57721ca7cd973d63ef817557aee Mon Sep 17 00:00:00 2001
From: Yabin Cui <yabinc@google.com>
Date: Fri, 2 Feb 2018 15:45:24 -0800
Subject: [PATCH] Avoid abort when calling pthread_mutex_destroy more than
 once.

Bug: http://b/72878088
Test: run bionic-unit-tests.
Change-Id: I0c3a6c5a625d187d5f32ec8c821cfdd5e807a671
---
 libc/bionic/pthread_mutex.cpp | 5 +++++
 tests/pthread_test.cpp        | 1 +
 2 files changed, 6 insertions(+)

diff --git a/libc/bionic/pthread_mutex.cpp b/libc/bionic/pthread_mutex.cpp
index e5f2a31bf..f1f72944d 100644
--- a/libc/bionic/pthread_mutex.cpp
+++ b/libc/bionic/pthread_mutex.cpp
@@ -943,11 +943,16 @@ int pthread_mutex_timedlock(pthread_mutex_t* mutex_interface, const timespec* ab
 int pthread_mutex_destroy(pthread_mutex_t* mutex_interface) {
     pthread_mutex_internal_t* mutex = __get_internal_mutex(mutex_interface);
     uint16_t old_state = atomic_load_explicit(&mutex->state, memory_order_relaxed);
+    if (old_state == 0xffff) {
+        // The mutex has been destroyed.
+        return EBUSY;
+    }
     uint16_t mtype  = (old_state & MUTEX_TYPE_MASK);
     if (mtype == MUTEX_TYPE_BITS_WITH_PI) {
         int result = PIMutexDestroy(mutex->ToPIMutex());
         if (result == 0) {
             mutex->FreePIMutex();
+            atomic_store(&mutex->state, 0xffff);
         }
         return result;
     }
diff --git a/tests/pthread_test.cpp b/tests/pthread_test.cpp
index 40059d027..8ac522344 100644
--- a/tests/pthread_test.cpp
+++ b/tests/pthread_test.cpp
@@ -1672,6 +1672,7 @@ struct PthreadMutex {
 
   void destroy() {
     ASSERT_EQ(0, pthread_mutex_destroy(&lock));
+    ASSERT_EQ(EBUSY, pthread_mutex_destroy(&lock));
   }
 
   DISALLOW_COPY_AND_ASSIGN(PthreadMutex);