1833147 - Enabling Firefox Profiler on large page crashes Firefox

Status: NEW

(Core :: Gecko Profiler, defect, P2)

Description

[Teal Dulcet [:tdulcet] (TB Council)]

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:109.0) Gecko/20100101 Firefox/113.0

Steps to reproduce:

1. Enable the Firefox Profiler.
2. Load a large page like this: https://tdulcet.github.io/Missing-Words/
3. Scroll up and down quickly until Firefox freezes.

Actual results:

Firefox freezes after a few seconds and never regains responsiveness.

Expected results:

Firefox should behave the same as when the profiler is not enabled. In other words, Firefox should not crash. I was able to reproduce this issue several times.

The above page has bad performance in Firefox (it has significantly better performance in Chrome), so I was trying to record a profile so I could report this performance issue to Mozilla. However, when Firefox is frozen, I of course have no way to get the resulting profile...

Comment 1

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

The severity field is not set for this bug.
:canova, could you have a look please?

For more information, please visit BugBot documentation.

Comment 2

[Nazım Can Altınova [:canova][:canaltinova on phabricator]]

I can't reproduce this on my machine but I have a rather powerful one. Will try to check it on Windows as well. Do you have any insights that could help me reproduce it?

Comment 3

[Teal Dulcet [:tdulcet] (TB Council)]

Attachment: image.png

I also have a relatively powerful system, with 12 CPU threads and 32 GiB of RAM. I used the default "Firefox" profiler settings. It takes around 30-45 seconds of scrolling for Firefox to fully freeze/crash. See the above screenshot from the latest Firefox Nightly 117 for example (note the "not responding" in the title bar).

Comment 4

[Teal Dulcet [:tdulcet] (TB Council)]

If you enable the "Native Allocations" profiler setting, it does hard crash and open the crash reporter, but I suspect this is a different bug. See this crash report for example: https://crash-stats.mozilla.org/report/index/48e34530-6d9e-4427-931e-7d9890230621

Comment 5

[Nazım Can Altınova [:canova][:canaltinova on phabricator]]

Yeah that crash on "native allocations" sounds like a different issue. Could be worth to file a separate bug.

I managed to reproduce the hang locally after a few try now. Managed to sample using Activity Monitor on macOS. Attaching the sample file.

It looks like the main thread is mostly busy inside mozilla::detail::EventQueueInternal<16ul>::PutEvent. Not sure about the couse of this though. Will investigate more.

Comment 6

[Nazım Can Altınova [:canova][:canaltinova on phabricator]]

Attachment: Sample of Firefox Nightly.zip

(had to zip it because it was slightly larger than the 10mb limit.)