Firefox got maniac
Update 2018-11-06: it was a fontconfig bug that is fixed in version 2.13.1-2. I can confirm that with this version all is back to normal, finally.
I don’t know what, I don’t know why, but Firefox behaves completely maniac on one of my computers. Opening simple tabs beats up 4 Web Content threads to nearly 100% CPU time, switching tabs the same.
By now I have:
- removed all of .mozilla
- started in –safe-mode
- disabled all extensions
- tried upstream provided Firefox instead of Debian’s
- made tripple flips while balancing three raw eggs on my nose
plus some more trials like removing locally installed fonts. But nothing has helped. Firefox is maniac. Opening a new tab with my Debian Q&A page sometimes, but not always, just shoots up the CPU usage as shown above. Yes, that are *4* Web Content all around/above 60%. This is all on an up-to-date Debian/sid.
Behavior is erratic. Often after suspend to ram and wake up it is getting worse. No idea what else I could do…
Anyone having an idea, please let me know!
Update 2018-10-04: For everyone interested, I am now suspecting a problem with the fontconfig library. The reasons why I come to this proposal is:
- the turning wheel on white background I experience often, I also see when new font packages are installed and fc-cache etc is updated
- another program (electron based) started to crash in libfontconfig with:
(gdb) bt #0 0x00007f416edf1dc0 in () at /usr/lib/x86_64-linux-gnu/libfontconfig.so.1 #1 0x00007f416ede5ede in FcConfigSubstituteWithPat () at /usr/lib/x86_64-linux-gnu/libfontconfig.so.1 #2 0x00007f416edf69fd in FcFontRenderPrepare () at /usr/lib/x86_64-linux-gnu/libfontconfig.so.1 #3 0x00007f416edf6e84 in FcFontMatch () at /usr/lib/x86_64-linux-gnu/libfontconfig.so.1
I hope I can actual show that this is the problem by finding a problematic font I have installed. I have lots of fonts in /usr/local, in particular CJK fonts that sometimes are a bit challenging.