I told ya! :) Cheers, Fedor.
On Sun, Sep 2, 2012 at 3:21 PM, Ben Noordhuis <[email protected]> wrote: > On Sun, Sep 2, 2012 at 8:34 AM, Navaneeth KN <[email protected]> > wrote: > > Hello, > > > > I have created a sample code that reporduces the problem. > > > > Code - https://gist.github.com/3595299 > > > > Please download it and run it. If you run it without any modification, > you > > should see the problems. Currently loop is iterating till 1000 and it is > > failing for me. In my friend's computer it was working fine for 1000 > > iterations. He modified it to a larger value to get the failure. So you > > might need to change that number to get a failure. > > > > Here is what the code does. > > > > * Calls "process" function 1000 times from JS. > > * "process" function UnWraps the class instance from V8 and assign that > to > > the workerdata instance. > > * Call uv_queue_work. > > * Worker thread will read a handle from the queue after acquiring a > mutex. > > This handle will be removed from the queue. > > * After doing the work, handle will be returned back to the queue. This > will > > also happen after acquiring a mutex. > > > > I got double free errors and segfault. But this is random and sometimes > the > > whole thing just works. In the "test.js", I have commented out calls to > > "sleep". Uncommenting this seems to fix the issue. > > > > I am wondering why this happens. Any help would be great. > > > > I am using Node v0.8.8 on Arch Linux. > > It's a thread safety issue but it's got nothing to do with mutexes: > the JS object gets garbage collected while the work request is > running. You need something like the patch below to make it safe. > > diff --git a/mutex-test.cc b/mutex-test.cc > index 3953a4d..3605612 100644 > --- a/mutex-test.cc > +++ b/mutex-test.cc > @@ -39,6 +39,8 @@ public: > > NativeLibrary* GetHandle(); > void ReturnHandle(NativeLibrary* handle); > + void Ref() { node::ObjectWrap::Ref(); } > + void Unref() { node::ObjectWrap::Unref(); } > > private: > Foo() > @@ -142,6 +144,7 @@ void after_work(uv_work_t *req) > data->callback->Call(Context::GetCurrent()->Global(), 2, argv); > } > > + data->clazz->Unref(); > data->callback.Dispose(); > delete data; > data = NULL; > @@ -184,6 +187,7 @@ Handle<Value> Foo::Process(const Arguments& args) > data->request.data = data; > data->callback = > Persistent<Function>::New(Local<Function>::Cast(args[1])); > data->clazz = ObjectWrap::Unwrap<Foo>(args.This()); > + data->clazz->Ref(); > > uv_queue_work(uv_default_loop(), &data->request, > perform_work_async, after_work); > > On a side note, Foo::~Foo() needs to call uv_mutex_destroy(). > > -- > Job Board: http://jobs.nodejs.org/ > Posting guidelines: > https://github.com/joyent/node/wiki/Mailing-List-Posting-Guidelines > You received this message because you are subscribed to the Google > Groups "nodejs" group. > To post to this group, send email to [email protected] > To unsubscribe from this group, send email to > [email protected] > For more options, visit this group at > http://groups.google.com/group/nodejs?hl=en?hl=en > -- Job Board: http://jobs.nodejs.org/ Posting guidelines: https://github.com/joyent/node/wiki/Mailing-List-Posting-Guidelines You received this message because you are subscribed to the Google Groups "nodejs" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/nodejs?hl=en?hl=en
