Open Bug 1652498 Opened 5 years ago Updated 4 years ago

Firefox on Windows stops responding after it has been running for a while

Categories

(Toolkit :: Application Update, defect)

Product:
Toolkit
Component:
Application Update
Version:
78 Branch
Type:
defect

Tracking

()

People

(Reporter: sahbi, Unassigned)

References

Details

(Whiteboard: [fidedi-ope])

User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.11; rv:68.0) Gecko/20100101 Firefox/68.0

Steps to reproduce:

  • Open a window with just a handful of tabs and proceed to work in other applications
  • Wait for an indeterminate amount of time (see "actual results" for more details)
  • While "waiting" I also opened some other tabs in Firefox, at this point everything is still okay
  • Eventually, try to open a new tab and load any web page

Actual results:

When I open the new tab and type in an address, the tab will change to its loading state but it will never actually finish. Trying to close the tab results in no change whatsoever, or Firefox may even hang completely (classic Windows-style white screen with "not responding" in the title bar). Opening a new tab or going back to ones that were already open doesn't work either, Firefox is stuck on the loading one.

Eventually Firefox does unfreeze but the tab is still "loading". I can't click on the "Send feedback" menu option (presumably because it wants to open a tab?) but "About Firefox" still works. Other menu options such as "Add-ons" expectedly don't work either. This particular freeze happened a couple of times over different Firefox versions, but I think in all cases Firefox was ready to restart to apply an update. In this case it was from 78.0.0 to 78.0.2 if I remember correctly (currently not near the device it's running on).

I also tried to kill the tab's process, but apparently every window is its own process and every tab is merely a thread inside of that. Shutting down and reopening Firefox does resolve the immediate problem of not being able to load new pages, but the underlying issue is likely still there.

This particular Firefox install is and always has been as vanilla as can be; it doesn't even have an ad-blocker add-on installed. If I remember it right, it doesn't even have Sync enabled either.

Expected results:

Tab should've loaded within seconds.

Hi sahbi,

It would help us if you can provide a memory report from about:memory.

Also, if you could reproduce this issue on our latest Nightly build, it can be downloaded from here: https://nightly.mozilla.org/
Then capture a performance profile using the Cleopatra add-on. You can get more info on how to install and use the Cleopatra add-on (that helps you get the performance profile) by going to:

https://developer.mozilla.org/en-US/docs/Mozilla/Performance/Profiling_with_the_Built-in_Profiler
https://perf-html.io/
Please also note that this add-on works only on FF Nightly, so that means you need to be able to reproduce the issue on Nightly first.

I will move this over to a component so developers can take a look over it. If is not the correct component please feel free to change it to an appropriate one.

Thanks for the report.

Best regards, Clara.

Component: Untriaged → Performance
Flags: needinfo?(sahbi)
Product: Firefox → Core

Hmm, if regular web pages won't open, the profiler likely won't be able to open either.

This sounds like a plain bug rather than like a performance problem. Two things that might cause this come to mind:

  • The event loop in the parent process might be in a bad state where only OS events (clicks etc) get processed but no Gecko events (timers, other delayed runnables).
  • Or the communication with child processes might be broken.

(In reply to sahbi from comment #0)

When I open the new tab and type in an address, the tab will change to its loading state but it will never actually finish.

Does the tab throbber animation play in this state?

Eventually Firefox does unfreeze but the tab is still "loading".

In this state, do toolbar button hover effects still work? Do tooltips appear?

I can't click on the "Send feedback" menu option (presumably because it wants to open a tab?) but "About Firefox" still works.

This indicates that the parent process at least responds to native events and can draw things.

Other menu options such as "Add-ons" expectedly don't work either.

"Add-ons" runs in the parent process though, so the "broken content process communication" hypothesis is weakened by this piece of evidence.

This particular freeze happened a couple of times over different Firefox versions, but I think in all cases Firefox was ready to restart to apply an update.

This again gives more evidence to the content process theory. If an update has been applied in the background, starting new content processes will fail.

I also tried to kill the tab's process, but apparently every window is its own process and every tab is merely a thread inside of that.

No, all windows run in the parent process. The tab contents are rendered by content processes (not necessarily one process per tab though).

Moving to DOM: Content Processes for now, but it could also be an Updater problem.

Component: Performance → DOM: Content Processes

This sounds like some updater issue, if this happens when "I think in all cases Firefox was ready to restart to apply an update"

(In reply to Clara Guerrero from comment #1)

Hi sahbi,
It would help us if you can provide a memory report from about:memory.

Also, if you could reproduce this issue on our latest Nightly build, it can be downloaded from here: https://nightly.mozilla.org/
Then capture a performance profile using the Cleopatra add-on.

Well as Markus pointed out, if I can't open any tabs then I can't open about:memory either. And depending on how Cleopatra works I may not be able to get to the necessary information from that as well.

(In reply to Markus Stange [:mstange] from comment #2)

When I open the new tab and type in an address, the tab will change to its loading state but it will never actually finish.

Does the tab throbber animation play in this state?

If by "tab throbber" you mean the following icon, then yes I do see that: chrome://global/skin/icons/loading.png
That's actually what I meant by "changes to its loading state". :>

Eventually Firefox does unfreeze but the tab is still "loading".

In this state, do toolbar button hover effects still work? Do tooltips appear?

If I recall correctly both hover effects and tooltips still work. Over the last 2 weeks or so we were doing some mass reshuffling a couple of times so I had to shut down the computer altogether, so unfortunately my most recent memory of this is from almost 3 weeks ago.

This particular freeze happened a couple of times over different Firefox versions, but I think in all cases Firefox was ready to restart to apply an update.

This again gives more evidence to the content process theory. If an update has been applied in the background, starting new content processes will fail.

Not sure if it qualifies as a new content process, but I noticed that refreshing a tab may also cause the issue.

I also tried to kill the tab's process, but apparently every window is its own process and every tab is merely a thread inside of that.

No, all windows run in the parent process. The tab contents are rendered by content processes (not necessarily one process per tab though).

Odd, in Windows's task manager I saw X Firefox processes (where X = the number of windows I had). I could expand the section and it would show additional entries, one for each tab inside that window. Since only the expandable entry had a PID, the childs must be threads. I didn't see the "master" process that is the ultimate (grand)parent of all. Not really that important here I guess, though.

Additionally, I believe I already tried to disable hardware acceleration but my computer has gotten a GPU upgrade yesterday. I don't think it has anything to do with the problem though, just mentioning it for completeness.

And lastly, I will be away from this particular Firefox instance for about 2 weeks, so I won't be able to generate any form of debugging information in the meantime. I can still clarify anything if necessary, however (as shown above).

All right, thanks. I can't think of any further questions. I agree with Olli that it does sound like an Updater problem, so I'll move the bug there.

Component: DOM: Content Processes → Application Update
Product: Core → Toolkit

(In reply to sahbi from comment #4)

Odd, in Windows's task manager I saw X Firefox processes (where X = the number of windows I had). I could expand the section and it would show additional entries, one for each tab inside that window. Since only the expandable entry had a PID, the childs must be threads. I didn't see the "master" process that is the ultimate (grand)parent of all. Not really that important here I guess, though.

This is indeed odd. Task Manager's groups are by application, not based on individual windows; normally, opening a second Firefox window does not create a second entry there or have any other observable effects in Task Manager. (also, Task Manager doesn't list threads, only processes)

So that makes me suspicious that perhaps opening that second window is actually starting an entire new instance of Firefox, and that action is triggering applying the waiting update. That leaves at least two open questions though: why is that new instance happening at all, and why isn't about:restartrequired showing up in those tabs instead of the loading indicator. The second question is a bit outside my area, but to start on the first one: can you provide some info about what you're doing to launch Firefox and open new windows? Are you using the default shortcuts the installer creates, or something customized?

Thanks again.

(In reply to Molly Howell (she/her) [:mhowell] from comment #6)

So that makes me suspicious that perhaps opening that second window is actually starting an entire new instance of Firefox, and that action is triggering applying the waiting update.

It might actually be the case that I opened a new window a while before the issue showed itself upon opening a new tab. I frequently use incognito windows for a short while, then go back to the main window.

can you provide some info about what you're doing to launch Firefox and open new windows? Are you using the default shortcuts the installer creates, or something customized?

Nothing special at all. To initially launch Firefox I simply click the taskbar icon, for new windows I just use Ctrl+N (or Ctrl+Shift+P for incognito) and Ctrl+T for tabs.

Flags: needinfo?(sahbi)

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

For more information, please visit auto_nag documentation.

Flags: needinfo?(ksteuber)
Severity: -- → S2
Flags: needinfo?(ksteuber)

Alright, I've been working on the problematic computer again and the issue occurred once more. The behaviour has changed a little though:

  • When I open a new tab and enter an address, the tab almost immediately stops "loading" and the address bar is emptied along with it
  • This time around I now can open the Firefox settings, which will be properly loaded in the same non-working tab (I even seem to be able to interact with any settings)
  • Replacing about:preferences with any other URL (e.g. https://google.com) still results in the same behaviour as in point 1 (almost immediately stops loading, URL is reset to (in this case) about:preferences)
  • Firefox no longer hangs entirely waiting for the tab to load
  • I can close this tab without issues, but opening a new one results in the same behaviour

I haven't checked if there's a pending update yet, I figured it was better to report it first and see if there are any required follow-up actions. Unless I have to reboot the problematic computer entirely, I'll keep Firefox open and in this state for further debugging purposes.

Any ideas how to further debug this? The issue still occurs around every update.

I realise things might be busy, but going 8 months without a single reply shouldn't be allowed to happen imo. Just today I once again experienced this issue, again when there was an update pending to be installed.

Sorry for the delay. It's hard to figure out what to advise here, because this problem is so unusual. Because of all the uncertainties, it's very difficult to determine where to go with this next, so I'm going to ask for a lot of information. Hopefully, that will help us narrow down the cause of the problem.

First, I would like to ask some clarifying questions:

  • What operating system are you running and what version is it? I see that you mentioned the Windows Task Manager, but your bug description says "Mac OS X 10.11".
  • What channel of Firefox are you using? Release? Beta? Dev Edition? Nightly?
  • Do you ever update Firefox in any way other than the built in updater? Do you, for example, use any sort of package manager?
  • Do you always use multiple browser windows? Have you ever seen this problem occur during a session where you never opened a second browser window?
  • When this problem occurs, do all open browser windows experience the same problem?
  • Does the timing of this usually coincide with having opened a new window recently?
  • What happens if you try to open a new window when this problem occurs? Does it open? Can it load pages?

Next, I would like to gather some debugging information. Navigate to about:config and set app.update.log to true. Next, navigate to about:support and note the path listed as "Update Folder". I'd like you to put that path somewhere where you will be able to find it next time this problem happens.

When this problem happens again, I'd like you to gather some information so that I can take a look:

  1. In each open Firefox window, I'd like you to check the Firefox version. I'd like to know if the versions of each window match. Ideally, I'd like you to navigate to about:support and note the version and build ID. If you can't access that, you should be able to use "Help->About Firefox" to determine the version. You may have to tap the "Alt" key to show the menu bar, if you are on Windows.

  2. Next, I'd like you a copy of all available update logs. For each open Firefox window, try to open the Browser Console ("Hamburger Menu->Web Developer->Browser Console" or "Hamburger Menu->More Tools->Browser Console", depending on which version of Firefox you are on). Do not close the consoles afterwards. Doing this for each window should just result in a single browser console being opened (with each subsequent attempt merely focusing the already open console). But, given the weird situation that you are in, it might be possible that each window opens its own console. Let me know how many consoles open. In each console that opens, filter the log messages with the filter AUS:SVC. Post the resulting logs here so I can look at them.

  3. I'd also like you to look in the update directory that we made a note of earlier. Open that directory, then navigate within it to updates/0. Does that directory contain a file called update.status? If so, I would like to know what it contains.

  4. Next, I would like you to check what version of Firefox is actually installed, and check if that matches the version that Firefox reported. Navigate to the directory that Firefox is installed in. On Windows, you can right click firefox.exe, click Properties, then click the Details tab. The version should be listed under "Product version". On Mac, you can right click on Firefox and click "Get Info". "General->Version" should indicate the installed version of Firefox.

Flags: needinfo?(sahbi)

so I'm going to ask for a lot of information

No problem, I prefer that over "try this, report back, try this, etc" anyways. =]

What operating system are you running and what version is it? I see that you mentioned the Windows Task Manager, but your bug description says "Mac OS X 10.11".

Correct, the issue appears on Windows 10 (Pro) but I simply filed this bug using a Mac. The Windows version is 2004.

What channel of Firefox are you using? Release? Beta? Dev Edition? Nightly?

I'm using the release/stable channel, the running version at the moment is 88.0.

Do you ever update Firefox in any way other than the built in updater? Do you, for example, use any sort of package manager?

Nope, I've always updated Firefox with the built-in updater. If an update is "stuck" and somehow won't install then I'll just download the latest version straight from the Mozilla website, but that rarely ever happened (maybe once or twice).

Do you always use multiple browser windows?

Actually most of the time I use a single window.

Have you ever seen this problem occur during a session where you never opened a second browser window?

Yes, when I wrote the previous comment from 5 days ago I was using a single window with only 4 tabs when it occurred. The computer had been restarted due to a power outage earlier that week and I only had those 4 tabs open since then.

When this problem occurs, do all open browser windows experience the same problem?

It's been a while since I used multiple windows since this issue started, but it does happen for all windows. I distinctly remember having an active incognito session and not wanting to close Firefox to temporarily fix the issue because said session would then be lost. Both windows had about 5-6 tabs each.

Does the timing of this usually coincide with having opened a new window recently?

Nope, since I'm using a single window most of the time. In most cases I have a "standard" set of tabs that I'll open right after starting up Firefox and then I won't close them (or even open new ones) for a pretty good while. I will usually refresh a couple of those tabs, however.

What happens if you try to open a new window when this problem occurs? Does it open? Can it load pages?

As I said it's been a while since I tried this, if I remember correctly I can open a new window but if I try to enter a URL it also shows the same symptoms as the first window.

Navigate to about:config and set app.update.log to true. Next, navigate to about:support and note the path listed as "Update Folder"

I've done this, but I also noticed a preference app.update.log.file so I enabled this alongside app.update.log. Not sure what the difference is though.

Next time it happens I'll try to remember as many details as possible, such as multiple windows, trying to open about:* pages, opening a developer console, etc. Some things may have changed over time since I initially reported it so I'll give a fresh full account of the circumstances and symptoms as well.

Flags: needinfo?(sahbi)

Alright, so it happened again once I went to Help > About Firefox. It started looking for an update and shortly after it prompted to restart. I closed this little window and tried to load a tab, which so far worked fine. However, about a minute later the problem started occurring again.

  1. I can still open Help > About Firefox. It says version 88.0 with a pending update (but it doesn't mention to what version). Just to be sure about the build number I checked on the .exe and it says 88.0.7775.

  2. I can also open the browser console, but I don't see any log messages matching AUS:SVC. I'm assuming you want me to check the Console tab and put the filter there, then try to load a URL within the same tab? Nothing happens in the console when I do that.

  3. The update directory does contain a file update.status, the contents of which are: applied-service. There's also a directory downloading within the update dir, but it's empty.

  4. After applying the update (I assume that's what you meant) the version reported on the .exe is 88.0.1 for Product version but 88.0.1.7794 for File version.

Now, some other details:

  • I have one non-incognito window with 6 tabs.
  • As I said I can still open About Firefox.
  • Opening a new or refreshing an existing tab both result in an infinite loading animation.
  • Opening about:* pages works, however.
  • The same goes for closing tabs, be it a stuck tab or one that's still showing an actual page.
  • Tooltips seem to still work as well, just like tab hover animations (like how it "highlights" the tab).
  • I can open a new window, but the same problem immediately occurs there.
  • For an incognito window I don’t even get a loading animation, it simply does nothing. Enter a URL, hit enter, the address bar is cleared and nothing else happens. Even better: I can’t even close this window. I can close a regular second window though.
  • Task manager lists 5 Firefox processes under Apps (I’m assuming this means foreground processes) and 5 under Background processes. All 10 of these processes have their own unique PIDs. I tried to kill the PID of the stuck window but it caused all Firefox processes to end.

Now, since Firefox has exited the update will be applied, so the problem has temporarily been resolved. I decided to downgrade Firefox back to 88.0.7775, once more had it check for updates (without applying) and tried to reproduce it again. I can still open tabs without issues. Just to be clear: I didn't restore a backup of my profile nor ProgramData, I downgraded just the application.

Everything up to this point was from last Friday. Today I checked Firefox again, the update still hasn't been applied but now the same problem occurs. After restarting Firefox the newer version is still 88.0.1.7794, just like before.

Thank you for this information, it is very helpful.

I just tried reproducing this problem again. I'm not sure what changed, because I don't think I'm doing anything differently than what I tried before, but I seem to be able to reproduce the problem now. After an update applies, if I start up another profile, I seem to get the situation you describe where new tabs just try to load forever.

I'm extremely busy at the moment, but as soon as I have some time to take a look, I'll make it a high priority to figure out what's going on here.

Status: UNCONFIRMED → NEW
Ever confirmed: true

No problem, if you need any other information just let me know.

Whiteboard: [fidedi-ope]
Severity: S2 → S3
You need to log in before you can comment on or make changes to this bug.