From 09dd6a62b7ef8cd3d519599ad5e0c67d000fc1fe Mon Sep 17 00:00:00 2001
From: Ivan Maidanski <ivmai@mail.ru>
Date: Mon, 11 Apr 2022 08:40:10 +0300
Subject: [PATCH] Do not use usleep between signals resend if ThreadSanitizer

Issue #236 (bdwgc).

For a reason, usleep() hangs trying to acquire some TSan lock when
called resend_lost_signals().

* pthread_stop_world.c [!GC_OPENBSD_UTHREADS && THREAD_SANITIZER]
(GC_usleep): Use sched_yield() in a loop instead of usleep() or
nanosleep(); update comment.
---
 pthread_stop_world.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/pthread_stop_world.c b/pthread_stop_world.c
index 9e146831b..281fb3528 100644
--- a/pthread_stop_world.c
+++ b/pthread_stop_world.c
@@ -36,8 +36,9 @@
 #ifndef GC_OPENBSD_UTHREADS
   GC_INLINE void GC_usleep(unsigned us)
   {
-#   ifdef LINT2
-      /* Workaround "waiting while holding a lock" warning.     */
+#   if defined(LINT2) || defined(THREAD_SANITIZER)
+      /* Workaround "waiting while holding a lock" static analyzer warning. */
+      /* Workaround a rare hang in usleep() trying to acquire TSan Lock.    */
       while (us-- > 0)
         sched_yield(); /* pretending it takes 1us */
 #   elif defined(CPPCHECK) /* || _POSIX_C_SOURCE >= 199309L */