napi mem leak test on valgrind

[jinfeihan57]

Version

v16.16.0

Platform

x86_64

Subsystem

Ubuntu20.04

What steps will reproduce the bug?

run this project node-addon-examples helloworld

How often does it reproduce? Is there a required condition?

Every time.

What is the expected behavior?

mem leak.
==3277602== LEAK SUMMARY:
==3277602==    definitely lost: 64 bytes in 1 blocks
==3277602==    indirectly lost: 0 bytes in 0 blocks
==3277602==      possibly lost: 304 bytes in 1 blocks
==3277602==    still reachable: 9,603 bytes in 30 blocks
==3277602==         suppressed: 0 bytes in 0 blocks
==3277602== Reachable blocks (those to which a pointer was found) are not shown.
==3277602== To see them, rerun with: --leak-check=full --show-leak-kinds=all
==3277602==
==3277602== For lists of detected and suppressed errors, rerun with: -s
==3277602== ERROR SUMMARY: 2 errors from 2 contexts (suppressed: 0 from 0)

What do you see instead?

ohos@ubuntu20:/node-addon-examples/1_hello_world/napi$ npm install --debug

> hello_world@0.0.0 install
> node-gyp rebuild

gyp info it worked if it ends with ok
gyp info using node-gyp@9.0.0
gyp info using node@16.16.0 | linux | x64
gyp info find Python using Python version 3.8.10 found at "/usr/bin/python3"
gyp info spawn /usr/bin/python3
gyp info spawn args [
gyp info spawn args   '/usr/local/lib/node_modules/npm/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/ohos/node-addon-examples/1_hello_world/napi/build/config.gypi',
gyp info spawn args   '-I',
gyp info spawn args   '/usr/local/lib/node_modules/npm/node_modules/node-gyp/addon.gypi',
gyp info spawn args   '-I',
gyp info spawn args   '/home/ohos/.cache/node-gyp/16.16.0/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/ohos/.cache/node-gyp/16.16.0',
gyp info spawn args   '-Dnode_gyp_dir=/usr/local/lib/node_modules/npm/node_modules/node-gyp',
gyp info spawn args   '-Dnode_lib_file=/home/ohos/.cache/node-gyp/16.16.0/<(target_arch)/node.lib',
gyp info spawn args   '-Dmodule_root_dir=/home/ohos/node-addon-examples/1_hello_world/napi',
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 spawn args ]
gyp info spawn make
gyp info spawn args [ 'BUILDTYPE=Debug', '-C', 'build' ]
make: Entering directory '/home/ohos/node-addon-examples/1_hello_world/napi/build'
  CC(target) Debug/obj.target/hello/hello.o
  SOLINK_MODULE(target) Debug/obj.target/hello.node
  COPY Debug/hello.node
make: Leaving directory '/home/ohos/node-addon-examples/1_hello_world/napi/build'
gyp info ok

added 1 package in 4s
ohos@ubuntu20:/node-addon-examples/1_hello_world/napi$ ls
binding.gyp  build  hello.c  hello.js  node_modules  package.json  package-lock.json  testvalgrind.c
ohos@ubuntu20:/node-addon-examples/1_hello_world/napi$ valgrind --leak-check=full node hello.js
==3277602== Memcheck, a memory error detector
==3277602== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al.
==3277602== Using Valgrind-3.15.0 and LibVEX; rerun with -h for copyright info
==3277602== Command: node hello.js
==3277602==
world
==3277602==
==3277602== HEAP SUMMARY:
==3277602==     in use at exit: 9,971 bytes in 32 blocks
==3277602==   total heap usage: 16,532 allocs, 16,500 frees, 15,121,778 bytes allocated
==3277602==
==3277602== 64 bytes in 1 blocks are definitely lost in loss record 13 of 32
==3277602==    at 0x4858E76: operator new(unsigned long) (vg_replace_malloc.c:344)
==3277602==    by 0xAD21C5: napi_module_register (in /usr/local/bin/node)
==3277602==    by 0x4A0D2F6: _register_hello (hello.c:23)
==3277602==    by 0x482EB99: call_init.part.0 (dl-init.c:72)
==3277602==    by 0x482ECA0: call_init (dl-init.c:30)
==3277602==    by 0x482ECA0: _dl_init (dl-init.c:119)
==3277602==    by 0x559F984: _dl_catch_exception (dl-error-skeleton.c:182)
==3277602==    by 0x48330CE: dl_open_worker (dl-open.c:758)
==3277602==    by 0x559F927: _dl_catch_exception (dl-error-skeleton.c:208)
==3277602==    by 0x4832609: _dl_open (dl-open.c:837)
==3277602==    by 0x487534B: dlopen_doit (dlopen.c:66)
==3277602==    by 0x559F927: _dl_catch_exception (dl-error-skeleton.c:208)
==3277602==    by 0x559F9F2: _dl_catch_error (dl-error-skeleton.c:227)
==3277602==
==3277602== 304 bytes in 1 blocks are possibly lost in loss record 25 of 32
==3277602==    at 0x485AB0A: calloc (vg_replace_malloc.c:762)
==3277602==    by 0x48319DA: allocate_dtv (dl-tls.c:286)
==3277602==    by 0x48319DA: _dl_allocate_tls (dl-tls.c:532)
==3277602==    by 0x49ED322: allocate_stack (allocatestack.c:622)
==3277602==    by 0x49ED322: pthread_create@@GLIBC_2.2.5 (pthread_create.c:660)
==3277602==    by 0xC11EE0: node::inspector::Agent::Start(std::string const&, node::DebugOptions const&, std::shared_ptr<node::ExclusiveAccess<node::HostPort, node::MutexBase<node::LibuvMutexTraits> > >, bool) (in /usr/local/bin/node)
==3277602==    by 0xACA168: node::Environment::InitializeInspector(std::unique_ptr<node::inspector::ParentInspectorHandle, std::default_delete<node::inspector::ParentInspectorHandle> >) (in /usr/local/bin/node)
==3277602==    by 0xB4C7B7: node::NodeMainInstance::CreateMainEnvironment(int*, node::EnvSerializeInfo const*) (in /usr/local/bin/node)
==3277602==    by 0xB4C8D6: node::NodeMainInstance::Run(node::EnvSerializeInfo const*) (in /usr/local/bin/node)
==3277602==    by 0xACE5A1: node::Start(int, char**) (in /usr/local/bin/node)
==3277602==    by 0x5463082: (below main) (libc-start.c:308)
==3277602==
==3277602== LEAK SUMMARY:
==3277602==    definitely lost: 64 bytes in 1 blocks
==3277602==    indirectly lost: 0 bytes in 0 blocks
==3277602==      possibly lost: 304 bytes in 1 blocks
==3277602==    still reachable: 9,603 bytes in 30 blocks
==3277602==         suppressed: 0 bytes in 0 blocks
==3277602== Reachable blocks (those to which a pointer was found) are not shown.
==3277602== To see them, rerun with: --leak-check=full --show-leak-kinds=all
==3277602==
==3277602== For lists of detected and suppressed errors, rerun with: -s
==3277602== ERROR SUMMARY: 2 errors from 2 contexts (suppressed: 0 from 0)
ohos@ubuntu20:/node-addon-examples/1_hello_world/napi$ node --version
v16.16.0

Additional information

No response

[legendecas]

napi_module_register is called once for each add-on at the time of dlopen. As we don't dlclose successfully registered add-ons on the main thread, deleting the module record is not feasible anyways.

This should be suppressed in the Valgrind report.

[bnoordhuis]

To expand further: node couldn't call dlclose() if it wanted to because it doesn't (and can't) know when the add-on is really, truly gone. Musl libc's dlclose() is a no-op for pretty much the same reason.

Worth mentioning that non-napi add-ons have the same issue: they're basically "forever" (until the process exits.)

I'll go ahead and close this as inactionable.

[jinfeihan57]

This should be suppressed in the Valgrind report.

How to suppressed this leak in the Valgrind report?