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Getting segmentation fault after receiving some callbacks from NAN layer #1543
Description
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:
- If, I am creating my subscriber object in sample application like this:
subscriber = new subscriber(ip, port);
Result: It is working fine.
- 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.
Activity
jay11ca39 commentedon Oct 11, 2018
Full backtrace:
jay11ca39 commentedon Oct 15, 2018
Hello @gireeshpunathil ,
Can you please provide your opinion for this issue.
It will be a great help.
gireeshpunathil commentedon Oct 15, 2018
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::uvAsynCallbackas well as illustrate the pub-sub cycle with threads in view?jay11ca39 commentedon Oct 15, 2018
Hi @gireeshpunathil ,
Following is the uv callback:
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:
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 commentedon Oct 16, 2018
Hi @gireeshpunathil ,
Can you please let me know, if any other information is needed.
gireeshpunathil commentedon Oct 18, 2018
I guess the failure is coming from:
((data ->nSubscriber)->jsCallback).Call(2, argv);wherein the
jsCallbackfield (av8::Functionobject) is not created in the currentcontextthat 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 commentedon Oct 18, 2018
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 commentedon Oct 18, 2018
nodejs/nan#813 is probably unrelated, but might be worth looking at.
My guess is that
jsCallbackis not properly initialized in some way. A stack trace for anode-gyp rebuild --debugbuild might help?jay11ca39 commentedon Oct 22, 2018
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 commentedon Oct 23, 2018
Hello @addaleax and @gireeshpunathil ,
Please let me know, if any additional information is required.
jay11ca39 commentedon Oct 25, 2018
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 commentedon Oct 25, 2018
@jay11ca39 - if I understand correctly, @addaleax 's suggestion was to:
node-gyp rebuild --debugand 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 commentedon Oct 25, 2018
Hello @gireeshpunathil ,
Following I have followed:
Built the native addon with: node-gyp rebuild --debug
Ran my sample application:
$ gdb node subscriber.js
Following is the output of $ bt full
jay11ca39 commentedon Oct 25, 2018
Following are my software version:
jay11ca39 commentedon Oct 26, 2018
Hello @addaleax and @gireeshpunathil ,
As I shared earlier, there is a strange observation on my subscriber sample:
subscriber = new subscriber(ip, port);Result: It is working fine.
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 ?
jay11ca39 commentedon Nov 13, 2018
Hello @gireeshpunathil ,
Any comment on my observation ?
gireeshpunathil commentedon Jun 26, 2019
@jay11ca39 - is this resolved?
gireeshpunathil commentedon Jul 15, 2019
inactive, closing