diff --git a/compiler-rt/lib/msan/msan_thread.cpp b/compiler-rt/lib/msan/msan_thread.cpp
--- a/compiler-rt/lib/msan/msan_thread.cpp
+++ b/compiler-rt/lib/msan/msan_thread.cpp
@@ -1,8 +1,13 @@
 
-#include "msan.h"
 #include "msan_thread.h"
-#include "msan_interface_internal.h"
 
+#include <signal.h>
+
+#include "msan.h"
+#include "msan_interface_internal.h"
+#include "sanitizer_common/sanitizer_linux.h"
+#include "sanitizer_common/sanitizer_platform_limits_posix.h"
+#include "sanitizer_common/sanitizer_posix.h"
 #include "sanitizer_common/sanitizer_tls_get_addr.h"
 
 namespace __msan {
@@ -43,10 +48,16 @@
 }
 
 void MsanThread::Init() {
+  __sanitizer_sigset_t set, old;
+  internal_sigfillset(&set);
+  internal_sigprocmask(SIG_SETMASK, &set, &old);
+
   SetThreadStackAndTls();
   CHECK(MEM_IS_APP(stack_.bottom));
   CHECK(MEM_IS_APP(stack_.top - 1));
   ClearShadowForThreadStackAndTLS();
+
+  internal_sigprocmask(SIG_SETMASK, &old, nullptr);
 }
 
 void MsanThread::TSDDtor(void *tsd) {