1 files changed, 43 insertions, 0 deletions
diff --git a/test/tsan/libdispatch/dispatch_once_deadlock.c b/test/tsan/libdispatch/dispatch_once_deadlock.c
new file mode 100644
index 000000000..8379f81a9
--- /dev/null
+++ b/test/tsan/libdispatch/dispatch_once_deadlock.c
@@ -0,0 +1,43 @@
+// Check that calling dispatch_once from a report callback works.
+
+// RUN: %clang_tsan %s -o %t
+// RUN: not %run %t 2>&1 | FileCheck %s
+
+#include <dispatch/dispatch.h>
+
+#include <pthread.h>
+#include <stdio.h>
+
+long g = 0;
+long h = 0;
+void f() {
+  static dispatch_once_t onceToken;
+  dispatch_once(&onceToken, ^{
+    g++;
+  });
+  h++;
+}
+
+void __tsan_on_report() {
+  fprintf(stderr, "Report.\n");
+  f();
+}
+
+int main() {
+  fprintf(stderr, "Hello world.\n");
+
+  f();
+
+  pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;
+  pthread_mutex_unlock(&mutex); // Unlock of an unlocked mutex
+
+  fprintf(stderr, "g = %ld.\n", g);
+  fprintf(stderr, "h = %ld.\n", h);
+  fprintf(stderr, "Done.\n");
+}
+
+// CHECK: Hello world.
+// CHECK: Report.
+// CHECK: g = 1
+// CHECK: h = 2
+// CHECK: Done.