Index: lib/msan/msan.cc
===================================================================
--- lib/msan/msan.cc
+++ lib/msan/msan.cc
@@ -55,7 +55,7 @@
 THREADLOCAL u32 __msan_retval_origin_tls;
 
 SANITIZER_INTERFACE_ATTRIBUTE
-THREADLOCAL u64 __msan_va_arg_tls[kMsanParamTlsSize / sizeof(u64)];
+ALIGNED(16) THREADLOCAL u64 __msan_va_arg_tls[kMsanParamTlsSize / sizeof(u64)];
 
 SANITIZER_INTERFACE_ATTRIBUTE
 THREADLOCAL u64 __msan_va_arg_overflow_size_tls;
Index: test/msan/signal_stress_test.cc
===================================================================
--- test/msan/signal_stress_test.cc
+++ test/msan/signal_stress_test.cc
@@ -1,8 +1,5 @@
 // RUN: %clangxx_msan -std=c++11 -O0 %s -o %t && %run %t
 //
-// AArch64 lacks var args instrumentation.
-// XFAIL: aarch64
-
 // Test that va_arg shadow from a signal handler does not leak outside.
 
 #include <signal.h>