1384796 - Tabs occasionally do not work

Status: RESOLVED WORKSFORME

(Core :: Web Painting, defect, P3)

Description

[Ralf Jung]

Attachment: This is how a broken tab looks like

Once or twice a week, it happens that a tab "breaks": Instead of loading any content, all it shows is a white background and a spinner.  I tried opening the Web console, but nothing shows up.  I have to restart the browser to get this fixed.

I suspect that one of the content processes somehow stops working properly?  I tried checking about_performance.  That shows 3 content processes (so one is missing?), and it takes a while to display the web pages (timing out talking to the 4th process?).  The broken tab does not show up in the list.

Some preferences:
dom.ipc.processCount;4
dom.ipc.processCount.web;1 (this is bold, but I did not customize it.  no idea what that means.)

about:support
Multiprocess Windows 	1/1 (Enabled by default)
Web Content Processes 	4/4
Stylo 	true (enabled by user)
(However, I have seen this problem already before enabling Stylo this morning.)

This is nightly 2017-07-24 (64bit, Linux).

Comment 1

[Ralf Jung]

Actually I could not even quit Firefox cleanly -- there was a process "left behind" so when I started nightly again, it claimed Firefox was still running.  I had to kill that process manually.

Comment 2

[Ralf Jung]

Possibly the instance of this that I saw today is just <https://bugzilla.mozilla.org/show_bug.cgi?id=1384804>. However, I have seen such tab freezes earlier, and <https://bugzilla.mozilla.org/show_bug.cgi?id=1384804> is definitely something new, so I think there are two separate bugs here.

Comment 3

[Ralf Jung]

I am still seeing this issue with yesterday's nightly.  Here's what I found in the browser console:

Hey developer! Want to see more verbose logging?  util.js:14:1
Type this into the console: DEFAULT_LOG_LEVEL=1  util.js:15:1
Unchecked lastError value: Error: Could not establish connection. Receiving end does not exist.  ExtensionCommon.jsm:399
Unchecked lastError value: Error: Could not establish connection. Receiving end does not exist.  ExtensionCommon.jsm:399
Loading mixed (insecure) display content “<URL REDACTED>” on a secure page[Learn More]  rs=ACT90oG1PnI9j6pLb9VKbnMU61LUAlbUpQ:635:365
Use of attributes’ nodeValue attribute is deprecated. Use value instead.  rs=ACT90oG1PnI9j6pLb9VKbnMU61LUAlbUpQ:593:248
Unchecked lastError value: Error: Could not establish connection. Receiving end does not exist.  ExtensionCommon.jsm:399

"Receiving end does not exist" sounds bad, could that be related?

Comment 4

[Ralf Jung]

Actually I am also seeing this in stable now.  And I found a way to reproduce it, or at least make it happen with very high probability:  When I restart my window manager ("kwin --replace"), the currently active tab in Firefox dies.  I need to restart the entire browser to fix that. I found nothing correlating with that in stdout/stderr, nor in the browser console.

Comment 5

[Jet Villegas (inactive)]

Does this still reproduce for you in Nightly?

Comment 6

[Ralf Jung]

Not anymore, no. I used to also see this on Beta, and it doesn't seem to happen there any more either.

Comment 7

[J. Ryan Stinnett [:jryans] (Use needinfo, replies may be slow)]

Thanks for the reply.  It sounds like the underlying issue may have been solved then, at least for Nightly and Beta.  I am not sure we can do much more with this report as-is.

If you see the issue occur again, please re-open the bug.