1790500 - File-descriptors are not closed under heavy load

Status: UNCONFIRMED

(Core :: DOM: Networking, defect, P3)

Description

[ed]

Attachment: fd-no-gc.html

User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:104.0) Gecko/20100101 Firefox/104.0

Steps to reproduce:

When using XHR to upload several thousand files, Firefox may enter a state where it stops closing file descriptors, eventually crashing. Appears to be exacerbated by heavy DOM load

An MRE is attached which should reproduce the issue after a few attempts; screenshot @ https://ocv.me/stuff/bugs/firefox/fd-no-gc.png

Possibly Linux-only bug; very brief testing on Windows came out negative

Actual results:

Firefox runs out of file descriptors and crashes in various ways

Expected results:

The file descriptors should be closed in a timely manner once the objects are nulled in javascript

Comment 1

[BugBot [:suhaib / :marco/ :calixte]]

The Bugbug bot thinks this bug should belong to the 'Core::DOM: Networking' component, and is moving the bug to that component. Please correct in case you think the bot is wrong.

Comment 2

[ed]

Attachment: fd-no-gc.html

prevent accidental POSTing to bmoattachments.org -- encourage local-hosting the mre instead

Comment 3

[ed]

Some observations I forgot to mention:

• clicking "GC" or "Measure" in about:memory will close the FDs
  • and sometimes it'll make the GC start running at an alright pace, closing FDs periodically as expected
  • but usually the number of open FDs will just start another climb
• there's been cases where, after all the files have finished uploading, the final handful of FDs will never be closed, permanently blocking safe-removal of USB flashdrives until the browsertab is closed or a GC is performed manually
  • I'll make a separate issue for that problem once I find a way to reproduce it reliably

Comment 4

[ed]

The related issue regarding the final handful of FDs "never" getting closed has been reported as issue 1792598

While far less severe than this bug (just a user annoyance rather than a full browser crash) it should be easier to reproduce