Index: lib/sanitizer_common/sanitizer_common_interceptors.inc
===================================================================
--- lib/sanitizer_common/sanitizer_common_interceptors.inc
+++ lib/sanitizer_common/sanitizer_common_interceptors.inc
@@ -3395,7 +3395,10 @@
   // its metadata. See
   // https://github.com/google/sanitizers/issues/321.
   char *res = REAL(strerror_r)(errnum, buf, buflen);
-  COMMON_INTERCEPTOR_WRITE_RANGE(ctx, res, REAL(strlen)(res) + 1);
+  if (res == buf)
+    COMMON_INTERCEPTOR_WRITE_RANGE(ctx, res, REAL(strlen)(res) + 1);
+  else
+    COMMON_INTERCEPTOR_INITIALIZE_RANGE(res, REAL(strlen)(res) + 1);
   return res;
 }
 #endif //(_POSIX_C_SOURCE >= 200112L || _XOPEN_SOURCE >= 600) && !_GNU_SOURCE ||
Index: lib/tsan/rtl/tsan_rtl_thread.cc
===================================================================
--- lib/tsan/rtl/tsan_rtl_thread.cc
+++ lib/tsan/rtl/tsan_rtl_thread.cc
@@ -345,6 +345,7 @@
   StatInc(thr, StatMopRange);
 
   if (*shadow_mem == kShadowRodata) {
+    DCHECK(!is_write);
     // Access to .rodata section, no races here.
     // Measurements show that it can be 10-20% of all memory accesses.
     StatInc(thr, StatMopRangeRodata);
Index: test/msan/Linux/strerror_r.c
===================================================================
--- /dev/null
+++ test/msan/Linux/strerror_r.c
@@ -0,0 +1,23 @@
+// RUN: %clang_msan -O0 -g %s -o %t && %run %t
+
+// UNSUPPORTED: android
+
+#define _GNU_SOURCE 1
+#include <assert.h>
+#include <string.h>
+#include <errno.h>
+
+int main() {
+  char buf[1000];
+  char* res = strerror_r(EINVAL, buf, sizeof(buf));
+  assert(res);
+  assert(res != buf);
+  volatile int z = strlen(res);
+
+  res = strerror_r(-1, buf, sizeof(buf));
+  assert(res);
+  assert(res == buf);
+  z = strlen(res);
+
+  return 0;
+}
Index: test/tsan/strerror_r.cc
===================================================================
--- /dev/null
+++ test/tsan/strerror_r.cc
@@ -0,0 +1,37 @@
+// RUN: %clangxx_tsan -O1 -DTEST_ERROR=ERANGE %s -o %t && %run %t 2>&1 | FileCheck --check-prefixes=CHECK,CHECK-SYS %s
+// RUN: %clangxx_tsan -O1 -DTEST_ERROR=-1 %s -o %t && not %run %t 2>&1 | FileCheck --check-prefixes=CHECK,CHECK-USER %s
+
+// UNSUPPORTED: android
+
+#define _GNU_SOURCE 1
+
+#include "test.h"
+
+#include <assert.h>
+#include <string.h>
+#include <errno.h>
+#include <stdio.h>
+
+char buffer[1000];
+
+void *Thread(void *p) {
+  barrier_wait(&barrier);
+  char* error = strerror_r(TEST_ERROR, buffer, sizeof(buffer));
+  assert(TEST_ERROR == -1 || error != buffer);
+  return 0;
+}
+
+int main() {
+  barrier_init(&barrier, 2);
+  pthread_t th[2];
+  pthread_create(&th[0], 0, Thread, 0);
+  pthread_create(&th[1], 0, Thread, 0);
+  pthread_join(th[0], 0);
+  pthread_join(th[1], 0);
+  fprintf(stderr, "DONE\n");
+}
+
+// CHECK-USER: WARNING: ThreadSanitizer: data race
+// CHECK-SYS-NOT: WARNING: ThreadSanitizer: data race
+
+// CHECK: DONE