diff --git a/compiler-rt/lib/asan/asan_stack.cc b/compiler-rt/lib/asan/asan_stack.cc
--- a/compiler-rt/lib/asan/asan_stack.cc
+++ b/compiler-rt/lib/asan/asan_stack.cc
@@ -35,10 +35,17 @@
   if (UNLIKELY(!asan_inited)) return;
 
   AsanThread *t = GetCurrentThread();
-  if (t && !t->isUnwinding() && WillUseFastUnwind(request_fast)) {
+  if (!t || t->isUnwinding()) {
+#if SANITIZER_CAN_SLOW_UNWIND
+    UnwindSlowWithOptionalContext(pc, context, max_depth);
+#endif
+    return;
+  }
+
+  ScopedUnwinding unwind_scope(t);
+  if (WillUseFastUnwind(request_fast)) {
     uptr top = t->stack_top();
     uptr bottom = t->stack_bottom();
-    ScopedUnwinding unwind_scope(t);
     if (!SANITIZER_MIPS || IsValidFrame(bp, top, bottom)) {
       UnwindFast(pc, bp, top, bottom, max_depth);
       return;
@@ -46,7 +53,7 @@
   }
 
 #if SANITIZER_CAN_SLOW_UNWIND
-    UnwindSlowWithOptionalContext(pc, context, max_depth);
+  UnwindSlowWithOptionalContext(pc, context, max_depth);
 #endif
 }