diff --git a/include/sanitizer/common_interface_defs.h b/include/sanitizer/common_interface_defs.h
index 4666318..e4ba2cb 100644
--- a/include/sanitizer/common_interface_defs.h
+++ b/include/sanitizer/common_interface_defs.h
@@ -48,6 +48,13 @@
 typedef unsigned long uptr;  // NOLINT
 typedef signed   long sptr;  // NOLINT
 #endif  // defined(_WIN64)
+#if defined(__x86_64__)
+// Since x32 uses ILP32 data model in 64-bit hardware mode,  we must use
+// 64-bit pointer to unwind stack frame.
+typedef unsigned long long uhwptr;  // NOLINT
+#else
+typedef uptr uhwptr;   // NOLINT
+#endif
 typedef unsigned char u8;
 typedef unsigned short u16;  // NOLINT
 typedef unsigned int u32;
diff --git a/lib/sanitizer_common/sanitizer_stacktrace.cc b/lib/sanitizer_common/sanitizer_stacktrace.cc
index 0a54e7c..28ee960 100644
--- a/lib/sanitizer_common/sanitizer_stacktrace.cc
+++ b/lib/sanitizer_common/sanitizer_stacktrace.cc
@@ -123,18 +123,18 @@
                                  uptr stack_top, uptr stack_bottom) {
   CHECK(size == 0 && trace[0] == pc);
   size = 1;
-  uptr *frame = (uptr*)bp;
-  uptr *prev_frame = frame;
+  uhwptr *frame = (uhwptr *)bp;
+  uhwptr *prev_frame = frame;
   while (frame >= prev_frame &&
-         frame < (uptr*)stack_top - 2 &&
-         frame > (uptr*)stack_bottom &&
+         frame < (uhwptr *)stack_top - 2 &&
+         frame > (uhwptr *)stack_bottom &&
          size < max_size) {
-    uptr pc1 = frame[1];
+    uhwptr pc1 = frame[1];
     if (pc1 != pc) {
-      trace[size++] = pc1;
+      trace[size++] = (uptr) pc1;
     }
     prev_frame = frame;
-    frame = (uptr*)frame[0];
+    frame = (uhwptr *)frame[0];
   }
 }