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SIGSEGV for address: 0x0 in ConcurrentMarking::Run #37106
Description
- Version:
v14.15.4 - Platform:
Linux 3d0c8550bcf0 4.19.121-linuxkit #1 SMP Tue Dec 1 17:50:32 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux
What steps will reproduce the bug?
I wish I knew, it happens sporadically in LIVE env, started to happen right after upgrade from node 12.20.0 to 14.15.4.
How often does it reproduce? Is there a required condition?
Service has very spiky Memory usage, looks like it happens after responding with a larger response (17MB). But having only this condition is not enough, we couldn't reproduce it in staging environment.
What is the expected behavior?
No crash.
What do you see instead?
Process is crashed with segfault.
Additional information
Got stacktrace using require("segfault-handler").registerHandler:
PID 1 received SIGSEGV for address: 0x0
/app_path_replaced_for_privacy_reasons/node_modules/segfault-handler/build/Release/segfault-handler.node(+0x2d76)[0x7f2c1c0d8d76]
/lib/x86_64-linux-gnu/libpthread.so.0(+0x12980)[0x7f2c1e6e2980]
nodejs(_ZN2v88internal17ConcurrentMarking3RunEiPNS1_9TaskStateE+0x554)[0xcff9c4]
nodejs(_ZThn32_N2v88internal14CancelableTask3RunEv+0x3b)[0xc6c9eb]
nodejs[0xa71405]
/lib/x86_64-linux-gnu/libpthread.so.0(+0x76db)[0x7f2c1e6d76db]
/lib/x86_64-linux-gnu/libc.so.6(clone+0x3f)[0x7f2c1e40071f]
Activity
schamberg97 commentedon Jan 28, 2021
@bolt-juri-gavshin could you perhaps share some code that can help to reproduce the issue, please?
bolt-juri-gavshin commentedon Jan 28, 2021
I would gladly do it, if I could reproduce it myself. As I wrote in the report, the error happens on LIVE only, sporadically, probably triggered by specific endpoint call (or calls), but the same call works just fine in staging. I can start this service with additional Node flags (or libraries, like "segfault-handler") to gather more data in the event of it's untimely death, let me know which ones...
schamberg97 commentedon Jan 28, 2021
What kind of service is it then? Is it some kind of HTTP(S) service? If so, do you use any web-frameworks?
also, do you use native modules?
bolt-juri-gavshin commentedon Jan 28, 2021
This is a gateway service with HTTP (non-S) endpoints, doing HTTP (non-S) requests.
The specific endpoint is pretty simple - do single outgoing request (using "http"), that returns a large response > 15M), then that "remote" response object is cleaned up and a response is sent.
Web framework is "express".
From the logs I see, that response for the request inside the service is received and deserialized successfully, but then service dies, during either cleanup or sending.
To my knowledge the only native module which can be related to that endpoint is "unix-dgram" (for syslog).
In the background we use "deasync" (used by "node-etcd") and "worker_threads", but timing suggests segfaults are related to that super-simple, but memory-hungry endpoint.
I suspect there is a bug in memory allocation or GC. I will continue to try to reproduce it in staging environment (and maybe even have some shareable JS code to reproduce it, but I don't have high hopes for it).
Update: "deasync" is not actually used - we use "node-etcd" without the
synchronousoption.bolt-juri-gavshin commentedon Jan 28, 2021
I rechecked, this specific service calls require only for 2 native modules,
deasyncandunix-dgram.deasyncmodule is unused, thus, the only candidate native module to mess with V8 isunix-dgram.schamberg97 commentedon Jan 28, 2021
You most probably need to rebuild these modules due to your Node.JS version upgrade. I have little experience with rebuilding modules, as I practice clean installs, but I believe you should look for npm rebuild. You can also try reinstalling the package (so it will get compiled again). Lemme know if it helps
bolt-juri-gavshin commentedon Jan 28, 2021
Our deployment is Docker based and
yarn installis called for every new build (i.e. we also practice clean installs), thus, npm rebuild will not do anything. I will upgrade "deasync" and "nan" versions, just in case.Strage thing, hundreds of other services we have are working just fine, only one service (this super-simple one) is heavily affected (~4 restarts per hour during daytime). The only difference I see, is that it's CPU and RAM usage pattern is very spiky (memory usage jumps from base of 220MB up to 3x and back multiple times per hour)
schamberg97 commentedon Jan 28, 2021
@bolt-juri-gavshin I know, it’s just without ability to replicate the issue, I am trying to troubleshoot other potential causes ;)
bolt-juri-gavshin commentedon Jan 29, 2021
@schamberg97 looks like the only way forward (to gather more info) is to put debug Node into LIVE env. Is there an easy way to get a debug version of Node using
aptor building from source is the only way?bolt-juri-gavshin commentedon Feb 1, 2021
Good morning! There are some new developments:
It was quite stable before (with the official binary):
@targos , I believe the "v8 engine" tag you added and removed is also correct here. My impression is that v8 used in 14.15.4 has a bug in GC (official Node 14.15.4 release):
Maybe someone has access to the release build output and can map that instruction to specific line in the code?
bolt-juri-gavshin commentedon Feb 15, 2021
Hello!
I tried to run the service on 14.15.5 and the error is still there, however, it has changed a bit.
The "general protection fault" is the same on both versions:
but segfault is now different:
14.15.4:
14.15.5:
Note the different instruction pointer
d7bebdvs the "original"cff9c4.@schamberg97 @targos
I hope this information will give you more clues on where to look for the possible problem.
bolt-juri-gavshin commentedon Aug 30, 2021
Duplicate of #37553. No problems observed in 14.17.4