Getting segmentation fault after receiving some callbacks from NAN layer

[jay11ca39]

Hello All,

I have written a native addon [Using NAN] for my cpp [pub-sub] library.

• Subscriber that is receving the events from the publisher.
• Calling the application callback.

So, my native addon is providing wrapper APIs for cpp library.

• Js application will create subscriber object and will subscribe for event. Internally I am creating c++ subscriber, subscribe to it and will register addon callback to cpp layer.
• I am using libuv for getting the asyn callback from c++ layer to addon layer, and then I am calling NAN callback for calling js callback.

For callback implementation in addon, I followed: #1171

Issue:
After receving some events on subscriber side, subscriber sample is crashing [Segmentation fault].

Crash logs:

(gdb) bt
#0  0x0000000000f87c74 in v8::internal::JSReceiver::GetCreationContext() ()
#1  0x0000000000afd25c in v8::Object::CreationContext() ()
#2  0x0000000001225044 in node::MakeCallback(v8::Isolate*, v8::Local<v8::Object>, v8::Local<v8::Function>, int, v8::Local<v8::Value>*) ()
#3  0x00007ffff47a539b in npubsub::NSubscriber::uvAsynCallback(uv_async_s*) ()
   from /home/jack/pubsubrepo/build/Release/pubsub.node
#4  0x000000000143e44b in uv__async_io (loop=0x21d0500 <default_loop_struct>, w=<optimized out>, events=<optimized out>) at ../deps/uv/src/unix/async.c:118
#5  0x000000000144ffa8 in uv__io_poll (loop=loop@entry=0x21d0500 <default_loop_struct>, timeout=-1) at ../deps/uv/src/unix/linux-core.c:400
#6  0x000000000143edd6 in uv_run (loop=0x21d0500 <default_loop_struct>, mode=UV_RUN_DEFAULT) at ../deps/uv/src/unix/core.c:368
#7  0x000000000122c1bd in node::Start(uv_loop_s*, int, char const* const*, int, char const* const*) ()
#8  0x0000000001224d03 in node::Start(int, char**) ()
#9  0x00007ffff6bd8f45 in __libc_start_main (main=0x8acef0 <main>, argc=8, argv=0x7fffffffe328, init=<optimized out>, fini=<optimized out>,
    rtld_fini=<optimized out>, stack_end=0x7fffffffe318) at libc-start.c:287

Observation:
There is a strange observation on my subscriber sample:

1. If, I am creating my subscriber object in sample application like this:

subscriber = new subscriber(ip, port);

Result: It is working fine.

2. If, I am creating the subscriber object like this

var subscriber = new subscriber(ip, port);

Result: It is crashing after receiving some events.

Environment details:

• Node.js Version: v8.11.1
• OS: Linux [Ubuntu : 14.04]

I am struggling with this issue since quite long. Any help will be appreciated.

Thanks in advance.

[jay11ca39]

Full backtrace:

(gdb) bt full
#0  0x0000000000f87c74 in v8::internal::JSReceiver::GetCreationContext() ()
No symbol table info available.
#1  0x0000000000afd25c in v8::Object::CreationContext() ()
No symbol table info available.
#2  0x0000000001225044 in node::MakeCallback(v8::Isolate*, v8::Local<v8::Object>, v8::Local<v8::Function>, int, v8::Local<v8::Value>*) ()
No symbol table info available.
#3  0x00007ffff47a539b in npubsub::NSubscriber::uvAsynCallback(uv_async_s*) ()
   from /home/jack/pubsubrepo/build/Release/pubsub.node
No symbol table info available.
#4  0x000000000143e44b in uv__async_io (loop=0x21d0500 <default_loop_struct>, w=<optimized out>, events=<optimized out>) at ../deps/uv/src/unix/async.c:118
        buf = "\001\000\000\000\000\000\000\000\320L2\002\000\000\000\000\200R2\002\000\000\000\000R\311\377\000\000\000\000\000`M0\002\000\000\000\000\200R2\002\000\000\000\000\240\235\377\377\377\177\000\000\320L2\002\000\000\000\000@\235\377\377\377\177", '\000' <repeats 19 times>, "\236\377\377\377\177\000\000@\236\377\377\377\177\000\000й\377\377\377\177\000\000\320L2\002\000\000\000\000\200R2\002\000\000\000\000\340\236\377\377\377\177\000\000\246\261\000\001\000\000\000\000\000\000\000\000\377\177\000\000\200\267\377\377\377\177\000\000\222\031\000\000\000\000\000\000@\242\060\002\000\000\000\000\240\235\377\377\377\177\000\000\001\002\000\000\000\000\000\000\230\302#\002\000\000\000\000V"...
        r = <optimized out>
        queue = {0x7fffffff9cb0, 0x7fffffff9cb0}
        q = <optimized out>
        h = <optimized out>
        __PRETTY_FUNCTION__ = "uv__async_io"
#5  0x000000000144ffa8 in uv__io_poll (loop=loop@entry=0x21d0500 <default_loop_struct>, timeout=-1) at ../deps/uv/src/unix/linux-core.c:400
        no_epoll_pwait = 0
        no_epoll_wait = 0
        events = {{events = 1, data = 8}, {events = 4294934528, data = 140737488331263}, {events = 4294948736, data = 18446666901737209855}, {events = 32767,
            data = 2390}, {events = 2390, data = 18446666901737177088}, {events = 32767, data = 140737488331472}, {events = 11889213, data = 18446641338091831296},
          {events = 32767, data = 11892500}, {events = 36866864, data = 17795858891150458880}, {events = 1, data = 140737488331328}, {events = 15, data = 0}, {
            events = 0, data = 36866864}, {events = 15, data = 9903397704933834752}, {events = 32513, data = 36741696}, {events = 36885152,
            data = 158341975186079744}, {events = 0, data = 140737488339376}, {events = 5407, data = 18446675560391245824}, {events = 32767,
            data = 140737488331504}, {events = 11892961, data = 18446641887847645184}, {events = 97, data = 15}, {events = 15, data = 1141615017}, {events = 256,
            data = 0}, {events = 4294951936, data = 369367220223}, {events = 0, data = 140737488339376}, {events = 5407, data = 18446675560391245824}, {
            events = 32767, data = 140737488331520}, {events = 17073464, data = 18446642300164505600}, {events = 32767, data = 16764929}, {events = 4294943680,
            data = 17795858891150491647}, {events = 32767, data = 3072}, {events = 52, data = 2475849424085975040}, {events = 0, data = 128}, {events = 0,
            data = 18446678103011885057}, {events = 32767, data = 140737488340104}, {events = 4294951936, data = 18446678103011917823}, {events = 32767,
            data = 36962976}, {events = 4294943712, data = 72314622060822527}, {events = 0, data = 36925360}, {events = 52, data = 18446643124798226432}, {
            events = 32767, data = 2305814462}, {events = 23, data = 51063781010178048}, {events = 0, data = 140737488331824}, {events = 11892500,
            data = 158341975186079744}, {events = 0, data = 4331925016}, {events = 4294943712, data = 64424542207}, {events = 0, data = 0}, {events = 36866864,
            data = 64424509440}, {events = 0, data = 6600781758}, {events = 2390, data = 158420521547988992}, {events = 0, data = 36866864}, {events = 4294951344,
            data = 24502788456447}, {events = 0, data = 140737488339376}, {events = 4294943888, data = 51079878547636223}, {events = 0, data = 5407}, {events = 15,
            data = 64424509440}, {events = 1141615017, data = 1099511627776}, {events = 4294944016, data = 18446678103011917823}, {events = 32767, data = 86}, {
            events = 4294951344, data = 24502788456447}, {events = 0, data = 140737488339376}, {events = 4294943904, data = 73329969509466111}, {events = 0,
            data = 0}, {events = 36885152, data = 18446643880712470528}, {events = 32767, data = 11891769}, {events = 36963696, data = 18446677484536594432}, {
            events = 32767, data = 140737488339824}, {events = 3974, data = 18446644086870900736}, {events = 32767, data = 16722579}, {events = 4294951928,
            data = 18446677484536627199}, {events = 32767, data = 140737488339960}, {events = 4294951200, data = 18446644567907270655}, {events = 32767,
            data = 16837356}, {events = 23137, data = 833223622656}, {events = 6, data = 48}, {events = 96, data = 18446644705346191360}, {events = 32767,
            data = 446676598790}, {events = 3974, data = 18446646766930497415}, {events = 32767, data = 140737488339824}, {events = 36957728, data = 0}, {
            events = 0, data = 140737488332416}, {events = 4294944560, data = 72174086435930111}, {events = 0, data = 140733193388156}, {events = 16839629,
            data = 23201413332992}, {events = 0, data = 140737488339376}, {events = 4294952072, data = 4295000063}, {events = 5406, data = 140737488337360}, {
            events = 4143421280, data = 32767}, {events = 0, data = 36963128}, {events = 3974, data = 158755425917861888}, {events = 0, data = 140737488332288}, {
            events = 11892500, data = 158341975186079744}, {events = 0, data = 4294967424}, {events = 4294944288, data = 30064803839}, {events = 0, data = 0}, {
            events = 36866864, data = 30064771072}, {events = 0, data = 6420377038}, {events = 4294944480, data = 158420521548021759}, {events = 0,
            data = 36961512}, {events = 0, data = 158755288478908416}, {events = 0, data = 36960056}, {events = 36958664, data = 51078912179961856}, {events = 0,
            data = 140737488339824}, {events = 4294944640, data = 158648738930262015}, {events = 0, data = 140737488338528}, {events = 4294950512, data = 32767}, {
            events = 0, data = 1407396362846208}, {events = 4294951072, data = 45788646375423}, {events = 0, data = 11889213}, {events = 4294944592,
            data = 51077898567712767}, {events = 0, data = 36866864}, {events = 16764929, data = 18446646217174679553}, {events = 32767, data = 4}, {events = 0,
            data = 18446674941915955200}, {events = 32767, data = 0}, {events = 36963128, data = 18446654600950841344}, {events = 32767, data = 140737488339824}, {
            events = 4294944752, data = 72325655831805951}, {events = 0, data = 140737488332688}, {events = 17078425, data = 18446646973088923648}, {
            events = 32767, data = 17063905067009}, {events = 36866864, data = 18446678068652146688}, {events = 32767, data = 50}, {events = 35633992,
            data = 18446677484536594432}, {events = 32767, data = 140737488334496}, {events = 36938288, data = 18446671918258978816}, {events = 32767,
            data = 140737488338544}, {events = 4294951792, data = 18446647247966863359}, {events = 32767, data = 16733988}, {events = 4294951792,
            data = 18446674941915987967}, {events = 32767, data = 140737488339824}, {events = 4294951200, data = 18446677484536627199}, {events = 32767,
            data = 140737488338464}, {events = 4294944928, data = 72358095719792639}, {events = 0, data = 140737488332896}, {events = 4294951792,
            data = 18446678068652179455}, {events = 32767, data = 140733193392005}, {events = 4294945280, data = 158755494637371391}, {events = 0,
            data = 140737488332960}, {events = 16837060, data = 158420521547988992}, {events = 0, data = 36961352}, {events = 4294944880,
            data = 18446674392160174079}, {events = 32767, data = 140737488339696}, {events = 36961352, data = 18446648553636888576}, {events = 32767,
            data = 140737488339232}, {events = 4294945280, data = 17046725230591}, {events = 0, data = 140737488339232}, {events = 11889213,
            data = 18446648553636888576}, {events = 32767, data = 11892500}, {events = 36866864, data = 73402296758697984}, {events = 1, data = 140737488333008}, {
            events = 6, data = 0}, {events = 0, data = 36866864}, {events = 6, data = 15407675440407511040}, {events = 32513, data = 140737488333312}, {
            events = 36885152, data = 158341975186079744}, {events = 0, data = 140737488339248}, {events = 3355, data = 18446675010635431936}, {events = 32767,
            data = 140737488333184}, {events = 11892961, data = 18446648897234272256}, {events = 32767, data = 6}, {events = 6, data = 3615702597}, {events = 256,
            data = 36866864}, {events = 4294951808, data = 369367220223}, {events = 0, data = 140737488339248}, {events = 3355, data = 18446675010635431936}, {
            events = 32767, data = 140737488333200}, {events = 17073464, data = 18446649515709562880}, {events = 32767, data = 16764929}, {events = 36866864,
            data = 18446675010635431936}, {events = 32767, data = 2875}, {events = 4294951216, data = 18446649653148549119}, {events = 32767, data = 11892961}, {
            events = 4294951072, data = 18446677553256103935}, {events = 32767, data = 140737488339976}, {events = 4294951808, data = 18446677553256103935}, {
            events = 32767, data = 11889213}, {events = 4294945408, data = 51077898567712767}, {events = 0, data = 36866864}, {events = 4294951216,
            data = 18446649721867993089}, {events = 32767, data = 12}, {events = 0, data = 158341975186079744}, {events = 0, data = 12}, {events = 832093222,
            data = 18446677553256103681}, {events = 32767, data = 36885152}, {events = 36866864, data = 18446675010635431936}, {events = 32767, data = 3391}, {
            events = 4294951216, data = 18446650477782269951}, {events = 32767, data = 11892961}, {events = 36866864, data = 51539607552}, {events = 0,
            data = 14259371923292028940}, {events = 0, data = 256}, {events = 0, data = 140737488339840}, {events = 86, data = 18446675010635431936}, {
            events = 32767, data = 3391}, {events = 4294951216, data = 18446650546501746687}, {events = 32767, data = 17073464}, {events = 4294945632,
            data = 72004821774794751}, {events = 0, data = 140737488333664}, {events = 11892961, data = 18446650752660144128}, {events = 32767, data = 7}...}
        pe = 0x7fffffffa1c0
        e = {events = 1, data = 8}
        real_timeout = -1
        q = <optimized out>
        w = <optimized out>
        sigset = {__val = {140737488336768, 0, 140737488331264, 16849474, 2, 140737488336448, 0, 6399, 36741696, 36812448, 140737488331216, 7, 0, 0, 0,
            140737336809392}}
        sigmask = 0
        base = 2082704301
        have_signals = <optimized out>
        nevents = 0
        count = 48
        nfds = 1
        fd = <optimized out>
        op = <optimized out>
        i = <optimized out>
        __PRETTY_FUNCTION__ = "uv__io_poll"
#6  0x000000000143edd6 in uv_run (loop=0x21d0500 <default_loop_struct>, mode=UV_RUN_DEFAULT) at ../deps/uv/src/unix/core.c:368
        timeout = <optimized out>
        r = 1
#7  0x000000000122c1bd in node::Start(uv_loop_s*, int, char const* const*, int, char const* const*) ()
No symbol table info available.
#8  0x0000000001224d03 in node::Start(int, char**) ()
No symbol table info available.
#9  0x00007ffff6bd8f45 in __libc_start_main (main=0x8acef0 <main>, argc=8, argv=0x7fffffffe328, init=<optimized out>, fini=<optimized out>,
    rtld_fini=<optimized out>, stack_end=0x7fffffffe318) at libc-start.c:287
        result = <optimized out>
        unwind_buf = {cancel_jmp_buf = {{jmp_buf = {0, 8750135525826613513, 9104920, 140737488347936, 0, 0, -8750135526510833399, -8750119565224980215},
              mask_was_saved = 0}}, priv = {pad = {0x0, 0x0, 0x15634d0 <__libc_csu_init>, 0x7fffffffe328}, data = {prev = 0x0, cleanup = 0x0,
              canceltype = 22426832}}}
        not_first_call = <optimized out>
#10 0x00000000008aee41 in _start ()
No symbol table info available.

[jay11ca39]

Hello @gireeshpunathil ,
Can you please provide your opinion for this issue.
It will be a great help.

[gireeshpunathil]

hello @jay11ca39 - how are you, nice to see you after some time!

Like last time, I am suspecting this has to do with one or more of: object scope, access or life cycle. Can you please provide your code of npubsub::NSubscriber::uvAsynCallback as well as illustrate the pub-sub cycle with threads in view?

[jay11ca39]

Hi @gireeshpunathil ,

Following is the uv callback:

void NSubscriber::uvAsynCallback(uv_async_t* handle)
{
	SubData *data =  (SubData *)static_cast<SubData*>(handle->data);

	//call js application callback
	Nan::HandleScope scope;
	Local<Object> addonMessage;

	v8::Local<v8::Value> argv[] {Nan::Null()};
	addonMessage = NMessage::NewInstance(0, argv);
	NMessage* unwrappedMessage = ObjectWrap::Unwrap<NMessage>(addonMessage);
	unwrappedMessage->nativeHandle = data->message;

	const unsigned argc = 2;
	v8::Local<v8::Value> topic = (Nan::New((data->topic).c_str())).ToLocalChecked();
	v8::Local<v8::Value> argv[argc] = { topic, addonMessage  };
	((data ->nSubscriber)->jsCallback).Call(2, argv);
}

typedef struct
{
	NSubscriber* nSubscriber; // Class object needs for callback as Application callback is stored in this class
	Message *message;
	std::string topic;
} SubData;

I am calling uvAsynCallback from the callback that I received from the native layer as follows:
uv_async_send(&(obj->uvAsyncHandle)); //In this handle's data I filled the subData.

Regarding the pub-sub model:

1. JS Publisher that is publishing message.
2. JS subscriber that is receiving the message.
   In Core CPP logic subscriber is having a thread that receive the message and call the application callback [In my case , cpp layer will call addon callback and from adddon callback I will call uv_async_send(&(obj->uvAsyncHandle)) which will call uvAsynCallback which will finally call the js callback.]

[jay11ca39]

Hi @gireeshpunathil ,
Can you please let me know, if any other information is needed.

[gireeshpunathil]

I guess the failure is coming from:

((data ->nSubscriber)->jsCallback).Call(2, argv);

wherein the jsCallback field (a v8::Function object) is not created in the current context that is prevalent in the JS execution context. If so, we want a new instance of this function created in the current execution context.

/cc @addaleax for an expert opinion.

[jay11ca39]

Yes @gireeshpunathil ,
You are right the issue is created by the line:
((data ->nSubscriber)->jsCallback).Call(2, argv);

When I commented this line, It was working fine.

Hello @addaleax
Can you please provide you opinion on this.

[addaleax]

nodejs/nan#813 is probably unrelated, but might be worth looking at.

My guess is that jsCallback is not properly initialized in some way. A stack trace for a node-gyp rebuild --debug build might help?

[jay11ca39]

Hello @addaleax ,

Following are the logs:

gyp info it worked if it ends with ok
gyp info using node-gyp@3.8.0
gyp info using node@8.9.4 | linux | x64
gyp info ok
gyp info it worked if it ends with ok
gyp info using node-gyp@3.8.0
gyp info using node@8.9.4 | linux | x64
gyp info spawn /usr/bin/python2
gyp info spawn args [ '/home/jack/pubsubrepo/node_modules/node-gyp/gyp/gyp_main.py',
gyp info spawn args 'binding.gyp',
gyp info spawn args '-f',
gyp info spawn args 'make',
gyp info spawn args '-I',
gyp info spawn args '/home/jack/pubsubrepo/build/config.gypi',
gyp info spawn args '-I',
gyp info spawn args '/home/jack/pubsubrepo/node_modules/node-gyp/addon.gypi',
gyp info spawn args '-I',
gyp info spawn args '/home/jack/.node-gyp/8.9.4/include/node/common.gypi',
gyp info spawn args '-Dlibrary=shared_library',
gyp info spawn args '-Dvisibility=default',
gyp info spawn args '-Dnode_root_dir=/home/jack/.node-gyp/8.9.4',
gyp info spawn args '-Dnode_gyp_dir=/home/jack/pubsubrepo/node_modules/node-gyp',
gyp info spawn args '-Dnode_lib_file=/home/jack/.node-gyp/8.9.4/<(target_arch)/node.lib',
gyp info spawn args '-Dmodule_root_dir=/home/jack/pubsubrepo/',
gyp info spawn args '-Dnode_engine=v8',
gyp info spawn args '--depth=.',
gyp info spawn args '--no-parallel',
gyp info spawn args '--generator-output',
gyp info spawn args 'build',
gyp info spawn args '-Goutput_dir=.' ]
gyp info ok
gyp info it worked if it ends with ok
gyp info using node-gyp@3.8.0
gyp info using node@8.9.4 | linux | x64
gyp info spawn make
gyp info spawn args [ 'BUILDTYPE=Release', '-C', 'build' ]
make: Entering directory `/home/jack/pubsubrepo/build'

CXX(target) Release/obj.target/npubsub/src/nmessage.o
CXX(target) Release/obj.target/npubsub/src/npublisher.o
CXX(target) Release/obj.target/npubsub/src/nsubscriber.o
../src/nsubscriber.cc: In static member function ‘static void npubsub::NSubscriber::uvAsynCallback(uv_async_t*)’:
../src/nsubscriber.cc:119:63: warning: ‘v8::Localv8::Value Nan::Callback::Call(int, v8::Localv8::Value*) const’ is deprecated [-Wdeprecated-declarations]
((data ->nSubscriber)->jsSubCallback).Call(1, argv);
^
In file included from ../src/nsubscriber.h:23:0,
from ../src/nsubscriber.cc:20:
../node_modules/nan/nan.h:1647:3: note: declared here
Call(int argc, v8::Localv8::Value argv[]) const {
^
SOLINK_MODULE(target) Release/obj.target/pubsub.node
COPY Release/pubsub.node
make: Leaving directory `/home/jack/pubsubrepo/build'
gyp info ok

[jay11ca39]

Hello @addaleax and @gireeshpunathil ,
Please let me know, if any additional information is required.

[jay11ca39]

Hello @addaleax and @gireeshpunathil ,

Previously I was using:
((data ->nSubscriber)->jsCallback).Call(2, argv);

Now, I used:
Nan::Call(((data ->nSubscriber)->jsSubCallback), Nan::GetCurrentContext()->Global(), 2, argv);

But, still it is giving the same crash.. :(

Can you please help me in this.?

[gireeshpunathil]

@jay11ca39 - if I understand correctly, @addaleax 's suggestion was to:

node-gyp rebuild --debug

and then run to crash with ulimit -c unlimited, and launch the core in gdb, collect the stack trace.

will you please follow that and get the stack?

[jay11ca39]

Hello @gireeshpunathil ,
Following I have followed:

1. Built the native addon with: node-gyp rebuild --debug

2. Ran my sample application:
   $ gdb node subscriber.js

Following is the output of $ bt full

Program received signal SIGSEGV, Segmentation fault.
0x0000000000afd251 in v8::Object::CreationContext() ()
(gdb)
(gdb) bt full
#0 0x0000000000afd251 in v8::Object::CreationContext() ()
No symbol table info available.
#1 0x0000000001225044 in node::MakeCallback(v8::Isolate*, v8::Localv8::Object, v8::Localv8::Function, int, v8::Localv8::Value) ()
No symbol table info available.
#2 0x00007ffff47a09da in Nan::Callback::Call_ (this=0x23044f8, isolate=0x21e8ac0, target=..., argc=2, argv=0x7fffffff9c70) at ../node_modules/nan/nan.h:1738
scope = {scope = {v8::HandleScope = {isolate_ = 0x21e8ac0, prev_next_ = 0x223f268, prev_limit_ = 0x2240b50}, escape_slot_ = 0x223f260}}
callback = {val_ = 0x0}
#3 0x00007ffff47a093c in Nan::Callback::Call (this=0x23044f8, argc=2, argv=0x7fffffff9c70) at ../node_modules/nan/nan.h:1658
isolate = 0x21e8ac0
scope = {v8::HandleScope = {isolate_ = 0x21e8ac0, prev_next_ = 0x223f250, prev_limit_ = 0x2240b50}, escape_slot_ = 0x223f248}
#4 0x00007ffff479f09b in npubsub::NSubscriber::uvAsynCallback (handle=0x2304500) at ../src/nsubscriber.cc:128
argc = 2
topic = {val_ = 0x223f240}
argv = {{val_ = 0x223f240}, {val_ = 0x223f238}}
data = 0x7fffd400c7b0
scope = {scope = {isolate_ = 0x21e8ac0, prev_next_ = 0x223f230, prev_limit_ = 0x223f230}}
addonEvent = {val_ = 0x223f238}
lock = {_M_device = 0x223f240, _M_owns = 56}
#5 0x000000000143e44b in uv__async_io (loop=0x21d0500 <default_loop_struct>, w=, events=) at ../deps/uv/src/unix/async.c:118
buf = "\001\000\000\000\000\000\000\000\020C2\002\000\000\000\000\220\235\377\377\377\177\000\000=2\002\000\000\000\000\060\235\377\377\377\177", '\000' <repeats 18 times>, "\360\235\377\377\377\177\000\000\060\236\377\377\377\177\000\000\300\271\377\377\377\177\000\000=2\002\000\000\000\000\020C2\002\000\000\000\000О\377\377\377\177\000\000\246\261\000\001\000\000\000\000\000\000\000\000\377\177\000\000p\267\377\377\377\177\000\000\306\031\000\000\000\000\000\000\360\222\060\002\000\000\000\000\220\235\377\377\377\177\000\000\001\002\000\000\000\000\000\000\230\302#\002\000\000\000\000/\n\000\000\000\000\000\000\340\235\377\377\377\177\000\000\020\000\000\000\000\000\000\000`=2\002\000\000\000\000\000"...
r =
queue = {0x7fffffff9cc0, 0x7fffffff9cc0}
q =
h =
PRETTY_FUNCTION = "uv__async_io"
#6 0x000000000144ffa8 in uv__io_poll (loop=loop@entry=0x21d0500 <default_loop_struct>, timeout=-1) at ../deps/uv/src/unix/linux-core.c:400
no_epoll_pwait = 0
no_epoll_wait = 0
events = {{events = 1, data = 8}, {events = 4294934528, data = 140737488331279}, {events = 4294949312, data = 18446641544250294271}, {events = 32767,
data = 16851024}, {events = 36849680, data = 158211923576356864}, {events = 0, data = 140737488331760}, {events = 11889213,
data = 18446641406811308032}, {events = 32767, data = 11892500}, {events = 36863536, data = 17795858891150458880}, {events = 1,
data = 140737488331344}, {events = 15, data = 0}, {events = 0, data = 36863536}, {events = 15, data = 16416795255191371776}, {events = 32513,
data = 140737488331760}, {events = 36881120, data = 158327681534918656}, {events = 0, data = 140737488339392}, {events = 5407,
data = 18446675629110722560}, {events = 32767, data = 140737488331520}, {events = 11892961, data = 11196979740672}, {events = 97, data = 15}, {
events = 15, data = 1050308343}, {events = 256, data = 0}, {events = 4294951952, data = 369367220223}, {events = 0, data = 140737488339392}, {
events = 5407, data = 18446675629110722560}, {events = 32767, data = 140737488331536}, {events = 17073464, data = 18446642368883982336}, {
events = 32767, data = 16764929}, {events = 4294967295, data = 17795858891150491392}, {events = 32767, data = 3072}, {events = 52,
data = 4104198811650359296}, {events = 0, data = 128}, {events = 0, data = 18446678171731361793}, {events = 32767, data = 140737488340120}, {
events = 4294951952, data = 18446678171731394559}, {events = 32767, data = 36967536}, {events = 4294943728, data = 72314622060822527}, {events = 0,
data = 140737488337792}, {events = 25, data = 18446643193517703168}, {events = 32767, data = 3822333006}, {events = 23, data = 51063781010178048}, {
events = 0, data = 140737488331840}, {events = 11892500, data = 158327681534918656}, {events = 0, data = 4331929576}, {events = 4294943728,
data = 64424542207}, {events = 0, data = 0}, {events = 36863536, data = 64424509440}, {events = 0, data = 8117300302}, {events = 36683344,
---Type to continue, or q to quit---
data = 158403204239851524}, {events = 0, data = 36863536}, {events = 4294951360, data = 24502788456447}, {events = 0, data = 140737488339392}, {
events = 4294943904, data = 51079878547636223}, {events = 0, data = 140733193393439}, {events = 15, data = 64424509440}, {events = 1050308343,
data = 1099511627776}, {events = 2110, data = 18446678171731361792}, {events = 32767, data = 86}, {events = 4294951360, data = 24502788456447}, {
events = 0, data = 140737488339392}, {events = 4294943920, data = 73329969509466111}, {events = 0, data = 0}, {events = 36881120,
data = 18446643949431947264}, {events = 32767, data = 11891769}, {events = 36968256, data = 18446677553256071168}, {events = 32767,
data = 140737488339840}, {events = 3974, data = 18446644155590377472}, {events = 32767, data = 16722579}, {events = 4294951944,
data = 18446677553256103935}, {events = 32767, data = 140737488339976}, {events = 4294951216, data = 18446644636626747391}, {events = 32767,
data = 16837356}, {events = 23121, data = 833223622656}, {events = 6, data = 48}, {events = 96, data = 18446644774065668096}, {events = 32767,
data = 446676598790}, {events = 3974, data = 18446646835649974151}, {events = 32767, data = 140737488339840}, {events = 36962288, data = 0}, {
events = 0, data = 140737488332432}, {events = 4294944576, data = 72174086435930111}, {events = 0, data = 140733193388156}, {events = 16839629,
data = 23201413332992}, {events = 0, data = 140737488339392}, {events = 4294952088, data = 4295000063}, {events = 5406, data = 140737488332672}, {
events = 4143421280, data = 32767}, {events = 0, data = 36967688}, {events = 3974, data = 158775010968731648}, {events = 0, data = 140737488332288}, {
events = 11892500, data = 158327681534918656}, {events = 0, data = 4294967424}, {events = 4294944304, data = 30064803839}, {events = 0, data = 0}, {
events = 36863536, data = 30064771072}, {events = 0, data = 5177157262}, {events = 4294944496, data = 158403204239884287}, {events = 0,
data = 36966072}, {events = 0, data = 158774873529778176}, {events = 0, data = 36964616}, {events = 36963224, data = 51078912179961856}, {events = 0,
data = 140737488339840}, {events = 4294944656, data = 158170451372179455}, {events = 0, data = 140737488338544}, {events = 4294950528, data = 32767}, {
events = 0, data = 1407396362846208}, {events = 4294951088, data = 45788646375423}, {events = 0, data = 11889213}, {events = 4294944608,
data = 51077898567712767}, {events = 0, data = 36863536}, {events = 16764929, data = 18446646285894156289}, {events = 32767, data = 4}, {events = 0,
data = 18446675010635431936}, {events = 32767, data = 0}, {events = 36967688, data = 18446654669670318080}, {events = 32767, data = 140737488339840}, {
events = 4294944768, data = 72325655831805951}, {events = 0, data = 140737488332704}, {events = 17078425, data = 18446647041808400384}, {
events = 32767, data = 17063905067009}, {events = 36863536, data = 18446678137371623424}, {events = 32767, data = 50}, {events = 35633992,
data = 18446677553256071168}, {events = 32767, data = 140737488334512}, {events = 36826928, data = 18446671986978455552}, {events = 32767,
data = 140737488338560}, {events = 4294951808, data = 18446647316686340095}, {events = 32767, data = 16733988}, {events = 4294951808,
data = 18446675010635464703}, {events = 32767, data = 140737488339840}, {events = 4294951216, data = 18446677553256103935}, {events = 32767,
data = 140737488338480}, {events = 4294944944, data = 72358095719792639}, {events = 0, data = 140737488332912}, {events = 4294951808,
data = 18446678137371656191}, {events = 32767, data = 140733193392005}, {events = 4294945296, data = 158775079688241151}, {events = 0,
data = 140737488332976}, {events = 16837060, data = 158403204239851520}, {events = 0, data = 36965912}, {events = 4294944896,
data = 18446674460879650815}, {events = 32767, data = 140737488339712}, {events = 36965912, data = 18446648622356365312}, {events = 32767,
data = 140737488339248}, {events = 4294945296, data = 17046725230591}, {events = 0, data = 140737488339248}, {events = 11889213,
data = 18446648622356365312}, {events = 32767, data = 11892500}, {events = 36863536, data = 73402296758697984}, {events = 1, data = 140737488333024}, {
events = 6, data = 0}, {events = 0, data = 36863536}, {events = 6, data = 6932845473724104704}, {events = 32513, data = 140737488333328}, {
events = 36881120, data = 158327681534918656}, {events = 0, data = 140737488339264}, {events = 3355, data = 18446675079354908672}, {events = 32767,
data = 140737488333200}, {events = 11892961, data = 18446648965953748992}, {events = 32767, data = 6}, {events = 6, data = 2764277574}, {events = 256,
data = 36863536}, {events = 4294951824, data = 369367220223}, {events = 0, data = 140737488339264}, {events = 3355, data = 18446675079354908672}, {
events = 32767, data = 140737488333216}, {events = 17073464, data = 18446649584429039616}, {events = 32767, data = 16764929}, {events = 36863536,
data = 18446675079354908672}, {events = 32767, data = 2875}, {events = 4294951232, data = 18446649721868025855}, {events = 32767, data = 11892961}, {
events = 4294951088, data = 18446677621975580671}, {events = 32767, data = 140737488339992}, {events = 4294951824, data = 18446677621975580671}, {
events = 32767, data = 11889213}, {events = 4294945424, data = 51077898567712767}, {events = 0, data = 36863536}, {events = 4294951232,
data = 18446649790587469825}, {events = 32767, data = 12}, {events = 0, data = 158327681534918656}, {events = 0, data = 12}, {events = 1189661742,
data = 18446677621975580417}, {events = 32767, data = 36881120}, {events = 36863536, data = 18446675079354908672}, {events = 32767, data = 3391}, {
events = 4294951232, data = 18446650546501746687}, {events = 32767, data = 11892961}, {events = 36863536, data = 51539607552}, {events = 0,
data = 5061911656062255116}, {events = 0, data = 256}, {events = 0, data = 140737488339856}, {events = 86, data = 18446675079354908672}, {
events = 32767, data = 3391}, {events = 4294951232, data = 18446650615221223423}, {events = 32767, data = 17073464}, {events = 4294945648,
data = 72004821774794751}, {events = 0, data = 140737488333680}, {events = 11892961, data = 18446650821379620864}, {events = 32767, data = 7}...}
pe = 0x7fffffffa1d0
e = {events = 1, data = 8}
real_timeout = -1
q =
w =
sigset = {__val = {2, 140737488336432, 0, 6451, 36737776, 36808496, 140737488331200, 7, 0, 0, 0, 0, 0, 36822480, 0, 140737336809392}}
sigmask = 0
base = 655307991
have_signals =
nevents = 0
count = 48
nfds = 1
fd =
op =
i =
PRETTY_FUNCTION = "uv__io_poll"
#7 0x000000000143edd6 in uv_run (loop=0x21d0500 <default_loop_struct>, mode=UV_RUN_DEFAULT) at ../deps/uv/src/unix/core.c:368
timeout =
r = 1
#8 0x000000000122c1bd in node::Start(uv_loop_s, int, char const* const*, int, char const* const*) ()
No symbol table info available.
#9 0x0000000001224d03 in node::Start(int, char**) ()
No symbol table info available.
#10 0x00007ffff6bd8f45 in __libc_start_main (main=0x8acef0

, argc=8, argv=0x7fffffffe338, init=, fini=,
rtld_fini=, stack_end=0x7fffffffe328) at libc-start.c:287
result =
unwind_buf = {cancel_jmp_buf = {{jmp_buf = {0, 3985235476459678095, 9104920, 140737488347952, 0, 0, -3985235476642928241, -3985250306478577265},
mask_was_saved = 0}}, priv = {pad = {0x0, 0x0, 0x15634d0 <__libc_csu_init>, 0x7fffffffe338}, data = {prev = 0x0, cleanup = 0x0,
canceltype = 22426832}}}
not_first_call =
#11 0x00000000008aee41 in _start ()
No symbol table info available.

[jay11ca39]

Following are my software version:

• Node: v8.9.4
• npm: 5.6.0
• node-gyp: 3.8.0
• nan: 2.11.1

[jay11ca39]

Hello @addaleax and @gireeshpunathil ,
As I shared earlier, there is a strange observation on my subscriber sample:

1. If, I am creating my subscriber object in sample application like this:

subscriber = new subscriber(ip, port);

Result: It is working fine.

2. If, I am creating the subscriber object like this

var subscriber = new subscriber(ip, port);

Result: It is crashing after receiving some events.

Here, what I am suspecting is :
garbage collector is collecting subscriber object for destroying in 2nd case because I do not have any
code that is using the subscriber object after creating in sample application.

Can you please provide your opinion on this ?