1 files changed, 11 insertions, 1 deletions
diff --git a/contrib/llvm-project/compiler-rt/lib/tsan/rtl/tsan_rtl.cpp b/contrib/llvm-project/compiler-rt/lib/tsan/rtl/tsan_rtl.cpp
index 3f3c0cce119c..13c9b770f50a 100644
--- a/contrib/llvm-project/compiler-rt/lib/tsan/rtl/tsan_rtl.cpp
+++ b/contrib/llvm-project/compiler-rt/lib/tsan/rtl/tsan_rtl.cpp
@@ -144,7 +144,7 @@ static void MemoryProfiler(Context *ctx, fd_t fd, int i) {
   WriteToFile(fd, buf.data(), internal_strlen(buf.data()));
 }
 
-static void BackgroundThread(void *arg) {
+static void *BackgroundThread(void *arg) {
   // This is a non-initialized non-user thread, nothing to see here.
   // We don't use ScopedIgnoreInterceptors, because we want ignores to be
   // enabled even when the thread function exits (e.g. during pthread thread
@@ -220,6 +220,7 @@ static void BackgroundThread(void *arg) {
       }
     }
   }
+  return nullptr;
 }
 
 static void StartBackgroundThread() {
@@ -494,14 +495,23 @@ int Finalize(ThreadState *thr) {
 void ForkBefore(ThreadState *thr, uptr pc) {
   ctx->thread_registry->Lock();
   ctx->report_mtx.Lock();
+  // Ignore memory accesses in the pthread_atfork callbacks.
+  // If any of them triggers a data race we will deadlock
+  // on the report_mtx.
+  // We could ignore interceptors and sync operations as well,
+  // but so far it's unclear if it will do more good or harm.
+  // Unnecessarily ignoring things can lead to false positives later.
+  ThreadIgnoreBegin(thr, pc);
 }
 
 void ForkParentAfter(ThreadState *thr, uptr pc) {
+  ThreadIgnoreEnd(thr, pc);  // Begin is in ForkBefore.
   ctx->report_mtx.Unlock();
   ctx->thread_registry->Unlock();
 }
 
 void ForkChildAfter(ThreadState *thr, uptr pc) {
+  ThreadIgnoreEnd(thr, pc);  // Begin is in ForkBefore.
   ctx->report_mtx.Unlock();
   ctx->thread_registry->Unlock();