diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_platform_limits_posix.h b/compiler-rt/lib/sanitizer_common/sanitizer_platform_limits_posix.h
--- a/compiler-rt/lib/sanitizer_common/sanitizer_platform_limits_posix.h
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_platform_limits_posix.h
@@ -579,7 +579,12 @@
 
 struct __sanitizer_siginfo_pad {
   // Require uptr, because siginfo_t is always pointer-size aligned on Linux.
+#if SANITIZER_X32
+  // X32 siginfo_t is aligned to 8 bytes.
+  u64 pad[128 / sizeof(u64)];
+#else
   uptr pad[128 / sizeof(uptr)];
+#endif
 };
 
 #if SANITIZER_LINUX