1 files changed, 43 insertions, 0 deletions
diff --git a/lib/tsan/lit_tests/free_race.c b/lib/tsan/lit_tests/free_race.c
new file mode 100644
index 000000000000..7a2ec0cdbed0
--- /dev/null
+++ b/lib/tsan/lit_tests/free_race.c
@@ -0,0 +1,43 @@
+// RUN: %clang_tsan -O1 %s -o %t && %t 2>&1 | FileCheck %s
+#include <pthread.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <stddef.h>
+#include <unistd.h>
+
+int *mem;
+pthread_mutex_t mtx;
+
+void *Thread1(void *x) {
+  pthread_mutex_lock(&mtx);
+  free(mem);
+  pthread_mutex_unlock(&mtx);
+  return NULL;
+}
+
+void *Thread2(void *x) {
+  sleep(1);
+  pthread_mutex_lock(&mtx);
+  mem[0] = 42;
+  pthread_mutex_unlock(&mtx);
+  return NULL;
+}
+
+int main() {
+  mem = (int*)malloc(100);
+  pthread_mutex_init(&mtx, 0);
+  pthread_t t;
+  pthread_create(&t, NULL, Thread1, NULL);
+  Thread2(0);
+  pthread_join(t, NULL);
+  pthread_mutex_destroy(&mtx);
+  return 0;
+}
+
+// CHECK: WARNING: ThreadSanitizer: heap-use-after-free
+// CHECK:   Write of size 4 at {{.*}} by main thread{{.*}}:
+// CHECK:     #0 Thread2
+// CHECK:     #1 main
+// CHECK:   Previous write of size 8 at {{.*}} by thread T1{{.*}}:
+// CHECK:     #0 free
+// CHECK:     #1 Thread1