[asan] Restore check removed by r332033

Needed by fiber handling code, and possibly other code paths.

Differential Revision: https://reviews.llvm.org/D46981

llvm-svn: 332553

diff --git a/compiler-rt/lib/asan/asan_thread.h b/compiler-rt/lib/asan/asan_thread.h
index a3052ec..6609192 100644 (file)
--- a/compiler-rt/lib/asan/asan_thread.h
+++ b/compiler-rt/lib/asan/asan_thread.h
@@ -117,6 +117,8 @@ class AsanThread {
       return nullptr;
     if (atomic_load(&stack_switching_, memory_order_relaxed))
       return nullptr;
+    if (!has_fake_stack())
+      return AsyncSignalSafeLazyInitFakeStack();
     return fake_stack_;
   }