User Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:33.0) Gecko/20100101 Firefox/33.0 Build ID: 20141013200257 Steps to reproduce: I watched a couple of video's on YouTube with the HTML5 player on. Actual results: For some reason the browser wouldn't load anymore video's and I had to quit Firefox. I soon discovered that Firefox still was running in the background and taking a lot of CPU, probably max. 70%. As I can tell, this only happens to me when I play random video's on YouTube, It's not always happens tough. Expected results: The browser should have been closed when I clicked the quit button.
Thanks for the report. Some thing you could try to narrow down the problem: 1) Test in a clean profile https://support.mozilla.org/en-US/kb/profile-manager-create-and-remove-firefox-profiles 2) Make sure you disabled all plugins in the new profile (such as flash and java) 3) Disable hardware acceleration https://support.mozilla.org/en-US/kb/troubleshoot-extensions-themes-to-fix-problems#w_turn-off-hardware-acceleration 4) Test with the latest development version (still using the test profile): http://nightly.mozilla.org/ 5) If the problem still persists, obtaining the debugging symbols <https://developer.mozilla.org/en/docs/Using_the_Mozilla_symbol_server#Downloading_symbols_on_Linux_Mac_OS_X> and trying to figure out what's happening during shutdown with gdb might be the way to figure this out.
Ok I'm a little bit further now. Seems like it really is something with HTML5 because Flash works absolutely fine on YouTube. As soon as I enable the HTML5 player in YouTube the problem seems to be back. However it doesn't always happens and it worked fine until Firefox 33 came out. A new profile doesn't work, I tried that several times. I also disabled all my plugins and that doesn't solve the problem as well. I haven't tried to disable hardware acceleration yet, so I will leave that as last.
I'm experiencing more or less the same issue with Firefox 36.0.1 on Xubuntu 14.10 x86_64 after visiting certain websites (phoronix.com is one of the triggers) the CPU usage will go op to 12% and remain at that level constantly. Closing Firefox the normal way doesn't kill the process, it will remain active and consume 12% of CPU resources, i have to manually kill the process to completely shutdown Firefox.
Turns out we have a simpler way to get a stack trace from hung Firefox on Linux: https://developer.mozilla.org/en-US/docs/How_to_Report_a_Hung_Firefox I don't know of a way to get troubleshooting info about videos, so this seems like the best chance to get additional information that might shed some light on the source of the problem.
Strange, as today in Firefox 36 and foreword this doesn't seem to be happening anymore.
Based on comment 5. REOPEN this bug if it happened again.
Status: UNCONFIRMED → RESOLVED
Last Resolved: 2 years ago
Resolution: --- → WORKSFORME
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