deps: v8: fix potential segfault in profiler

This change fixes a potential segfault in the sampling heap profiler. This landed as part of a larger change upstream [1]. This is the minimal backport that avoids the segfault. [1]: https://git.io/vdTYL PR-URL: nodejs/node#15498 Reviewed-By: Ben Noordhuis <[email protected]> Reviewed-By: James M Snell <[email protected]>
ayojs · Sep 30, 2017 · 0f82870 · 0f82870
1 parent 5a2dd5c
commit 0f82870
Showing 1 changed file with 5 additions and 2 deletions.
diff --git a/deps/v8/src/profiler/sampling-heap-profiler.h b/deps/v8/src/profiler/sampling-heap-profiler.h
@@ -172,8 +172,11 @@ class SamplingAllocationObserver : public AllocationObserver {
   void Step(int bytes_allocated, Address soon_object, size_t size) override {
     USE(heap_);
     DCHECK(heap_->gc_state() == Heap::NOT_IN_GC);
-    DCHECK(soon_object);
-    profiler_->SampleObject(soon_object, size);
+    if (soon_object) {
+      // TODO(ofrobots): it would be better to sample the next object rather
+      // than skipping this sample epoch if soon_object happens to be null.
+      profiler_->SampleObject(soon_object, size);
+    }
   }
 
   intptr_t GetNextStepSize() override { return GetNextSampleInterval(rate_); }