commit 0fc4f4f2b94c9167e85f79683997f0f72705814c
author Brian Silverman <brians> Mon Dec 29 21:38:51 2014 -0800
committer Brian Silverman <brians> Mon Dec 29 21:42:07 2014 -0800
tree 725e60a12e39ea1397f5f53fba483f404bdd7007
parent d65f5e0afb7df204aecd78b86cdf3a0e9818350f

fix tsan occasionally complaining about condition variables

Change-Id: If575818c293c31678c3333834ce6da72045b6a45

aos/linux_code/ipc_lib/aos_sync.c

diff --git a/aos/linux_code/ipc_lib/aos_sync.c b/aos/linux_code/ipc_lib/aos_sync.c
index e6c6ba1..569b73d 100644
--- a/aos/linux_code/ipc_lib/aos_sync.c
+++ b/aos/linux_code/ipc_lib/aos_sync.c
@@ -178,7 +178,7 @@
 }
 
 int futex_wait(mutex *m) {
-  if (*m) {
+  if (__atomic_load_n(m, __ATOMIC_SEQ_CST)) {
     return 0;
   }
   const int ret = sys_futex_wait(m, 0, NULL);
@@ -210,7 +210,7 @@
 }
 
 void condition_wait(mutex *c, mutex *m) {
-  const mutex wait_start = *c;
+  const mutex wait_start = __atomic_load_n(c, __ATOMIC_RELAXED);
 
   mutex_unlock(m);
 
@@ -221,7 +221,8 @@
     if (ret != 0) {
       // If it failed for some reason other than somebody else doing a wake
       // before we actually made it to sleep.
-      if (__builtin_expect(*c == wait_start, 0)) {
+      if (__builtin_expect(__atomic_load_n(c, __ATOMIC_RELAXED) == wait_start,
+                           0)) {
         // Try again if it was because of a signal.
         if (ret == -EINTR) continue;
         PELOG(FATAL, -ret, "FUTEX_WAIT(%p, %" PRIu32 ", NULL, NULL, 0) failed",
@@ -234,7 +235,7 @@
     // If we got requeued above, this will just succeed the first time because
     // the person waking us from the above wait (changed to be on the mutex
     // instead of the condition) will have just set it to 0.
-    while (__atomic_exchange_n(m, 2, __ATOMIC_SEQ_CST) != 0) {
+    while (__atomic_exchange_n(m, 2, __ATOMIC_ACQ_REL) != 0) {
       const int ret = sys_futex_wait(m, 2, NULL);
       if (ret != 0) {
         // Try again if it was because of a signal or somebody else unlocked it