1067194 - libxul.so uses 100% CPU

Status: RESOLVED INCOMPLETE

(Firefox :: Untriaged, defect)

Description

[xrs]

User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:32.0) Gecko/20100101 Firefox/32.0
Build ID: 20140911151253

Steps to reproduce:

I started firefox, initiated my session with my session manager. All my windows and tabs opened. After a while of browsing cpu started to burst at 100%. 


Actual results:

There is a firefox thread which is highly using cpu. 

Using gdb to inspect the thread I see:
(gdb) bt
#0  0x00007f47180cd63c in ?? () from /opt/firefox/libxul.so
#1  0x00007f47181afdf1 in ?? () from /opt/firefox/libxul.so
#2  0x00007f47181cd1b3 in ?? () from /opt/firefox/libxul.so
#3  0x00007f47181cd377 in ?? () from /opt/firefox/libxul.so
#4  0x00007f47181cd412 in ?? () from /opt/firefox/libxul.so
#5  0x00007f47181cfc52 in ?? () from /opt/firefox/libxul.so
#6  0x00007f47181d374f in ?? () from /opt/firefox/libxul.so
#7  0x00007f4717e385d4 in ?? () from /opt/firefox/libxul.so
#8  0x00007f47181d3857 in ?? () from /opt/firefox/libxul.so
#9  0x00007f471caeaa05 in ?? () from /opt/firefox/libnspr4.so
#10 0x00007f471dd99b50 in start_thread (arg=<optimized out>) at pthread_create.c:304
#11 0x00007f471cf38e6d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:112
#12 0x0000000000000000 in ?? ()

That's what "perf top" shows. 
75,73%  libxul.so                          [.] 0x1b21d0
  2,05%  libpthread-2.13.so                 [.] pthread_mutex_lock
  2,01%  libpthread-2.13.so                 [.] __pthread_mutex_unlock_usercnt
  1,95%  python2.7                          [.] 0x95c82
  1,34%  libavcodec.so.53.35.0              [.] 0x207c02
  1,01%  libsamplerate.so.0.1.8             [.] 0x3d7a
  0,87%  libpthread-2.13.so                 [.] pthread_self

Comment 1

[xrs]

Side note: I disabled all my firefox addons. The performance issue remained.

Comment 2

[[:Aleksej]]

Thanks for the report.

If you find that it's caused by a particular page being open, you can use the JS profiler to find out why (Shift-F5).

Else, maybe https://developer.mozilla.org/en-US/docs/Mozilla/Performance/Profiling_with_the_Built-in_Profiler

Comment 3

[[:Aleksej]]

(I've never used the latter, and don't know if that makes sense.)

Comment 4

[Liviu Cirdei]

Due to the lack of response from the reporter I will change the status of this bug to Resolved:Incomplete.

Reporter, fell free to reopen it if you still have the issue on latest Firefox versions.