--prof hangs, dropping: overflow

[l-bujakowski]

• Version: 16.3.0, 14.17.0, 10.24.1
• Platform: Ubuntu 18.04.5 LTS (Linux 4.15.0-144-generic doc: added node-forward TC meeting 2014-10-15 #148-Ubuntu SMP Sat May 8 02:33:43 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux)
• Subsystem: profiler

What steps will reproduce the bug?

node --prof fib.js

//fib.js
function fib(n) {
 if(n > 1){
 return fib(n-1) + fib(n-2)
 } else {
 return n;
 }
}

for(var i=0; i<40; i++){
 console.log(fib(i));
}

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

I always get this issue, every time.

What is the expected behavior?

• fib.js should be run (it should print to stdout)
• node should exit after
• isolate-{something}-v8.log file should be generated
• this generated file should be readable to node --prof-process

What do you see instead?

• fib.js is never run, there is no output, even passing a file with sytax error or unexisting file, or even no filename doesn't make a difference
• node hangs, it never exists (I've waited up to 15 minutes so far)
• isolate-{something}-v8.log file is generated, but the output seems odd:

node --prof-process isolate-0x62557e0-9113-v8.log 2>err.txt >output.txt

output.txt:

Statistical profiling result from isolate-0x62557e0-9113-v8.log, (708 ticks, 0 unaccounted, 0 excluded).

 [Shared libraries]:
 ticks total nonlib name
 2 0.3% /lib/x86_64-linux-gnu/libc-2.27.so
 1 0.1% /home/lbujakowski/.nvm/versions/node/v14.15.1/bin/node

 [JavaScript]:
 ticks total nonlib name

 [C++]:
 ticks total nonlib name
 702 99.2% 99.6% __lll_lock_wait
 2 0.3% 0.3% write
 1 0.1% 0.1% do_futex_wait.constprop.1

 [Summary]:
 ticks total nonlib name
 0 0.0% 0.0% JavaScript
 705 99.6% 100.0% C++
 0 0.0% 0.0% GC
 3 0.4% Shared libraries

 [C++ entry points]:
 ticks cpp total name

 [Bottom up (heavy) profile]:
 Note: percentage shows a share of a particular caller in the total
 amount of its parent calls.
 Callers occupying less than 1.0% are not shown.

 ticks parent name
 702 99.2% __lll_lock_wait

The stderr got a lot of dropping: overflow errors:

cat err.txt | uniq -c

 697 dropping: overflow

Additional information

I'm using nvm, so I've tried this with few versions.
I have no issue with node 8.17.0 and 9.11.2. I get the bug on 10+ versions (I've tested with: 10.24.1, 14.17.0 and 16.3.0).
I've also tried using official node docker images, but same thing - old versions work, but 10+ don't.

I need to profile my app, but it seems I cannot profile at all. Does someone have an idea what might be the cause of this problem, or how to nail it?

[Ayase-252]

even passing a file with sytax error or unexisting file, or even no filename doesn't make a difference

Could you reinstall Node.js? I suspect that something might messed up in your system. By the way, I have tested on Ubuntu 21.04 and Node.js v16.3.0, it works well.

[l-bujakowski]

even passing a file with sytax error or unexisting file, or even no filename doesn't make a difference

Could you reinstall Node.js? I suspect that something might messed up in your system. By the way, I have tested on Ubuntu 21.04 and Node.js v16.3.0, it works well.

I've tried with official docker images and different node versions run by nvm.

[targos]

@nodejs/diagnostics