Open Bug 1861870 Opened 4 months ago Updated 1 month ago

Memory leak in firefox


(Core :: Performance, defect)

Firefox 119



Performance Impact low


(Reporter: iwillnotsignin, Unassigned)


(Keywords: memory-footprint, perf:resource-use)


(3 files)

Attached file memory-report.json.gz

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:109.0) Gecko/20100101 Firefox/119.0

Steps to reproduce:

  1. Start firefox.
  2. Open youtube (or pretty much any website)
  3. Leave PC unattended for a few hours

Actual results:

Firefox Main Process memory keeps increasing (10+GB) until the PC crashes, even with just a few tabs open.
This happens within a few hours of leaving firefox open on almost any website.

Issue exists for at least the past few months, with latest firefox versions.

Expected results:

Firefox memory should not leak

Attached file about_support.txt

This ( seems to suggest some possible profiling I could run.
If any of these would be helpful, kindly let me know and I will run them.

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

Component: Untriaged → Performance
Product: Firefox → Core

More details - Once the issue starts, the memory usage seems to be increasing continuously, at around 0.1-1MB every second (according to Windows Task Manager).

This bug was moved into the Performance component.

:iwillnotsignin, could you make sure the following information is on this bug?

  • For slowness or high CPU usage, capture a profile with, upload it and share the link here.
  • ✅ For memory usage issues, capture a memory dump from about:memory and attach it to this bug.
  • Troubleshooting information: Go to about:support, click "Copy raw data to clipboard", paste it into a file, save it, and attach the file here.

If the requested information is already in the bug, please confirm it is recent.

Thank you.

Flags: needinfo?(iwillnotsignin)

About support has already been updated.
CPU usage is not high according to task manager, just the memory. And until the system RAM runs out and starts paging, everything remains responsive.
I can still run the profiler and upload it if required.

Flags: needinfo?(iwillnotsignin)
Attached file about_support_raw.json

The Performance Impact Calculator has determined this bug's performance impact to be low. If you'd like to request re-triage, you can reset the Performance Impact flag to "?" or needinfo the triage sheriff.

Platforms: Windows
Resource impact: Severe

Performance Impact: --- → low
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