From ecbf64648fc164efce0570579a781d341369fc95 Mon Sep 17 00:00:00 2001
From: Evgeniy Stepanov <eugeni.stepanov@gmail.com>
Date: Fri, 22 Mar 2013 11:59:49 +0000
Subject: [PATCH] [msan] Handle dlopen() failure in dlopen interceptor.

llvm-svn: 177728
---
 compiler-rt/lib/msan/msan_interceptors.cc | 2 +-
 compiler-rt/lib/msan/tests/msan_test.cc   | 7 +++++++
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/compiler-rt/lib/msan/msan_interceptors.cc b/compiler-rt/lib/msan/msan_interceptors.cc
index 677b8a8f9df9..958e19d215a8 100644
--- a/compiler-rt/lib/msan/msan_interceptors.cc
+++ b/compiler-rt/lib/msan/msan_interceptors.cc
@@ -807,7 +807,7 @@ INTERCEPTOR(void *, dlopen, const char *filename, int flag) {
   EnterLoader();
   link_map *map = (link_map *)REAL(dlopen)(filename, flag);
   ExitLoader();
-  if (!__msan_has_dynamic_component()) {
+  if (!__msan_has_dynamic_component() && map) {
     // If msandr didn't clear the shadow before the initializers ran, we do it
     // ourselves afterwards.
     UnpoisonMappedDSO(map);
diff --git a/compiler-rt/lib/msan/tests/msan_test.cc b/compiler-rt/lib/msan/tests/msan_test.cc
index 2120f0efa30d..60d4fd526e19 100644
--- a/compiler-rt/lib/msan/tests/msan_test.cc
+++ b/compiler-rt/lib/msan/tests/msan_test.cc
@@ -1397,6 +1397,13 @@ TEST(MemorySanitizer, dlopen) {
 
   delete[] path;
 }
+
+// Regression test for a crash in dlopen() interceptor.
+TEST(MemorySanitizer, dlopenFailed) {
+  const char *path = "/libmsan_loadable_does_not_exist.x86_64.so";
+  void *lib = dlopen(path, RTLD_LAZY);
+  ASSERT_EQ(0, lib);
+}
 } // namespace
 
 TEST(MemorySanitizer, scanf) {