Re: www/firefox 81 opens too many files

[maya%NetBSD.org@localhost]

On Tue, Oct 13, 2020 at 12:08:09PM +0200, Marc Baudoin wrote:
> Hi,
> 
> Since www/firefox has been upgraded to version 81, it uses way
> more files than before on my system (NetBSD/amd64 9.0) after only
> a few minutes using it and either crashes leaving a core file or
> makes me quit it because other software complains there are too
> many open files.
> 
> I didn't change the maximum number of open files on the system:
> 
> % sysctl kern.maxfiles
> kern.maxfiles = 3404
> 
> and www/firefox version 80 worked perfectly that way.
> 
> Version 81.0.2 (recently committed) also shows the same problem.
> 
> Is anybody else having that problem? Does anybody know if it's
> specific to NetBSD or if it's also happening on other operating
> systems?

Hi Marc,

I have put together some websites that do this
(twitch.tv, even without any video open, tweetdeck.twitter.com)

Each of these open about 1170 fds per tab.
Easy to hit the global limit of 3404 system-wide.

I can get the number down by:
mkdir /backup
mv /usr/X11R7/lib/X11/fonts/100dpi/ /backup
mv /usr/X11R7/lib/X11/fonts/75dpi/ /backup

And it is down to 391.

It looks like these website tabs open every single font on the system.
It might be a fingerprinting technique.




----- how I found this -----

After identifying such a website, I did:

ktruss -i -o output timeout 30s firefox --safe-mode https://twitch.tv/directory/all
kdump -x output > output.kdumped

In the meantime identify the PID with many FDs opened:
for i in `pgrep firefox`; do echo $i; fstat -n -p $i |wc -l; done

grep -C 100 'PID_USING_MANY_FDS.*open' output.kdumped

grepping for NAMI,

 28715  28715 firefox  NAMI  "/usr/X11R7/lib/X11/fonts/100dpi/luBIS10-ISO8859-1.pcf.gz"
 28715  28715 firefox  NAMI  "/usr/X11R7/lib/X11/fonts/100dpi/luBIS10.bdf"
 28715  28715 firefox  NAMI  "/usr/X11R7/lib/X11/fonts/100dpi/luBIS12-ISO8859-1.pcf.gz"
 28715  28715 firefox  NAMI  "/usr/X11R7/lib/X11/fonts/100dpi/luBIS12.bdf"
 28715  28715 firefox  NAMI  "/usr/X11R7/lib/X11/fonts/100dpi/luBIS14-ISO8859-1.pcf.gz"
 28715  28715 firefox  NAMI  "/usr/X11R7/lib/X11/fonts/100dpi/luBIS14.bdf"
 28715  28715 firefox  NAMI  "/usr/X11R7/lib/X11/fonts/100dpi/luBIS18-ISO8859-1.pcf.gz"
 28715  28715 firefox  NAMI  "/usr/X11R7/lib/X11/fonts/100dpi/luBIS18.bdf"
 28715  28715 firefox  NAMI  "/usr/X11R7/lib/X11/fonts/100dpi/luBIS19-ISO8859-1.pcf.gz"
 28715  28715 firefox  NAMI  "/usr/X11R7/lib/X11/fonts/100dpi/luBIS19.bdf"
 28715  28715 firefox  NAMI  "/usr/X11R7/lib/X11/fonts/100dpi/luBIS24-ISO8859-1.pcf.gz"
 28715  28715 firefox  NAMI  "/usr/X11R7/lib/X11/fonts/100dpi/luBIS24.bdf"
 28715  28715 firefox  NAMI  "/usr/X11R7/lib/X11/fonts/100dpi/luBS08-ISO8859-1.pcf.gz"
 28715  28715 firefox  NAMI  "/usr/X11R7/lib/X11/fonts/100dpi/luBS08.bdf"
 28715  28715 firefox  NAMI  "/usr/X11R7/lib/X11/fonts/100dpi/luBS10-ISO8859-1.pcf.gz"
 28715  28715 firefox  NAMI  "/usr/X11R7/lib/X11/fonts/100dpi/luBS10.bdf"
 28715  28715 firefox  NAMI  "/usr/X11R7/lib/X11/fonts/100dpi/luBS12-ISO8859-1.pcf.gz"
...