On Tue, Apr 12, 2016 at 7:11 PM, <benjamin.pas...@gmail.com> wrote: > Hi, > > we (Microsoft VS Code team) are tracking down a very weird native crash in > our use of node.js (5.10.0, V8 46) that only ever shows up since we updated > from node.js 4.x (V8 45). It seems that changes (around the Garbace > Collector?) in V8 46 have an impact to the crash. > > Specifically, we are using the node-weak module > (https://github.com/TooTallNate/node-weak) to be able to get weak references > onto JavaScript objects. This used to work relatively good in node.js 4.x, > but with node.js 5.x we suddenly get the entire node.js program to terminate > with a fatal crash. > > Today we were finally able to track the location of where the crash > originates and it seems to happen when our application simply calls into a > property of the object that is weakly referenced. This call at one point > reaches the following assertion: > > void Object::VerifyApiCallResultType() { > #if DEBUG > if (!(IsSmi() || IsString() || IsSymbol() || IsSpecObject() || > IsHeapNumber() || IsSimd128Value() || IsUndefined() || IsTrue() || > IsFalse() || IsNull())) { > FATAL("API call returned invalid object"); > } > #endif // DEBUG > } > > > The process terminates from the FATAL call, as none of the previous checks > in this method hold. > > > Now, the interesting question is: How would it be possible to have a JS > object where calling properties on it would fail in such a fatal way? It > seems to us that the object we are calling a property on is a pointer to a > location in memory where no V8 object exists anymore. It almost seems that > the object was garbage collected (or moved to another address?) without the > JS side (or more specifically the node-weak side) getting to know. > > > Since this only reproduces with using node-weak, it seems very likely that > there is an issue with either node-weak or NAN. In fact, node-weak is > calling into SetWeak() > (https://github.com/TooTallNate/node-weak/blob/master/src/weakref.cc#L174) > and relies on the fact that the callback passed in is triggered and maybe > this callback is not triggered anymore in a sync fashion but rather async? > > > I would appreciate some pointers if there is something that could have > probably changed in V8 46 that could have an impact on this.
If you have a simple test case (stress on 'simple'), I'll have a look. -- -- v8-dev mailing list v8-dev@googlegroups.com http://groups.google.com/group/v8-dev --- You received this message because you are subscribed to the Google Groups "v8-dev" group. To unsubscribe from this group and stop receiving emails from it, send an email to v8-dev+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
