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Why is gnome-shell writing 17783 lines per second of these errors to my /var/log/syslog file?:

gnome-shell: ERROR:broker_posix.cc(46)] Received unexpected number of handles
gnome-shell: ERROR:command_buffer_proxy_impl.cc(96)] ContextResult::kFatalFailure: AllocateAndMapSharedMemory failed

Details:

My computer gave me a warning of running out of disk space this morning, so I cleared up 20 GB with rm -rf ~/.local/share/Trash/*. Running df -h showed that I had 20 GB free on the root drive.

I then left the computer alone for a few hours.

To my surprise, when I got back on it recently, it was right back down to 0 MB free again! What happened?

Running sudo ncdu / allowed me to scan around and look at disk usage, and I saw that /var/log/syslog file is 43.5 GiB. Could this be it? Did this log suddenly grow really fast, filling up the 20 GB of space I had just freed? What writes to this log file? Why? Does it normally auto-rotate, or self-limit to some max size? Should it?

Running less /var/log/syslog shows this:

Jul 16 00:06:09 gabriel-Latitude-7490 gnome-shell[503208]: [503636:1:0100/000000.711106:ERROR:broker_posix.cc(46)] Received unexpected number of handles
Jul 16 00:06:09 gabriel-Latitude-7490 gnome-shell[503208]: [503636:1:0100/000000.711119:ERROR:command_buffer_proxy_impl.cc(96)] ContextResult::kFatalFailure: AllocateAndMapSharedMemory failed
Jul 16 00:06:09 gabriel-Latitude-7490 gnome-shell[503208]: [503636:1:0100/000000.711219:ERROR:broker_posix.cc(46)] Received unexpected number of handles
Jul 16 00:06:09 gabriel-Latitude-7490 gnome-shell[503208]: [503636:1:0100/000000.711232:ERROR:command_buffer_proxy_impl.cc(96)] ContextResult::kFatalFailure: AllocateAndMapSharedMemory failed
Jul 16 00:06:09 gabriel-Latitude-7490 gnome-shell[503208]: [503636:1:0100/000000.711331:ERROR:broker_posix.cc(46)] Received unexpected number of handles
Jul 16 00:06:09 gabriel-Latitude-7490 gnome-shell[503208]: [503636:1:0100/000000.711344:ERROR:command_buffer_proxy_impl.cc(96)] ContextResult::kFatalFailure: AllocateAndMapSharedMemory failed
Jul 16 00:06:09 gabriel-Latitude-7490 gnome-shell[503208]: [503636:1:0100/000000.711445:ERROR:broker_posix.cc(46)] Received unexpected number of handles
Jul 16 00:06:09 gabriel-Latitude-7490 gnome-shell[503208]: [503636:1:0100/000000.711459:ERROR:command_buffer_proxy_impl.cc(96)] ContextResult::kFatalFailure: AllocateAndMapSharedMemory failed
Jul 16 00:06:09 gabriel-Latitude-7490 gnome-shell[503208]: [503636:1:0100/000000.711560:ERROR:broker_posix.cc(46)] Received unexpected number of handles
Jul 16 00:06:09 gabriel-Latitude-7490 gnome-shell[503208]: [503636:1:0100/000000.711573:ERROR:command_buffer_proxy_impl.cc(96)] ContextResult::kFatalFailure: AllocateAndMapSharedMemory failed
Jul 16 00:06:09 gabriel-Latitude-7490 gnome-shell[503208]: [503636:1:0100/000000.711673:ERROR:broker_posix.cc(46)] Received unexpected number of handles
Jul 16 00:06:09 gabriel-Latitude-7490 gnome-shell[503208]: [503636:1:0100/000000.711687:ERROR:command_buffer_proxy_impl.cc(96)] ContextResult::kFatalFailure: AllocateAndMapSharedMemory failed
Jul 16 00:06:09 gabriel-Latitude-7490 gnome-shell[503208]: [503636:1:0100/000000.711787:ERROR:broker_posix.cc(46)] Received unexpected number of handles
Jul 16 00:06:09 gabriel-Latitude-7490 gnome-shell[503208]: [503636:1:0100/000000.711801:ERROR:command_buffer_proxy_impl.cc(96)] ContextResult::kFatalFailure: AllocateAndMapSharedMemory failed
Jul 16 00:06:09 gabriel-Latitude-7490 gnome-shell[503208]: [503636:1:0100/000000.711902:ERROR:broker_posix.cc(46)] Received unexpected number of handles
Jul 16 00:06:09 gabriel-Latitude-7490 gnome-shell[503208]: [503636:1:0100/000000.711917:ERROR:command_buffer_proxy_impl.cc(96)] ContextResult::kFatalFailure: AllocateAndMapSharedMemory failed
Jul 16 00:06:09 gabriel-Latitude-7490 gnome-shell[503208]: [503636:1:0100/000000.712018:ERROR:broker_posix.cc(46)] Received unexpected number of handles
Jul 16 00:06:09 gabriel-Latitude-7490 gnome-shell[503208]: [503636:1:0100/000000.712031:ERROR:command_buffer_proxy_impl.cc(96)] ContextResult::kFatalFailure: AllocateAndMapSharedMemory failed
Jul 16 00:06:09 gabriel-Latitude-7490 gnome-shell[503208]: [503636:1:0100/000000.712131:ERROR:broker_posix.cc(46)] Received unexpected number of handles
Jul 16 00:06:09 gabriel-Latitude-7490 gnome-shell[503208]: [503636:1:0100/000000.712144:ERROR:command_buffer_proxy_impl.cc(96)] ContextResult::kFatalFailure: AllocateAndMapSharedMemory failed
Jul 16 00:06:09 gabriel-Latitude-7490 gnome-shell[503208]: [503636:1:0100/000000.712246:ERROR:broker_posix.cc(46)] Received unexpected number of handles
Jul 16 00:06:09 gabriel-Latitude-7490 gnome-shell[503208]: [503636:1:0100/000000.712260:ERROR:command_buffer_proxy_impl.cc(96)] ContextResult::kFatalFailure: AllocateAndMapSharedMemory failed
Jul 16 00:06:09 gabriel-Latitude-7490 gnome-shell[503208]: [503636:1:0100/000000.712361:ERROR:broker_posix.cc(46)] Received unexpected number of handles
Jul 16 00:06:09 gabriel-Latitude-7490 gnome-shell[503208]: [503636:1:0100/000000.712374:ERROR:command_buffer_proxy_impl.cc(96)] ContextResult::kFatalFailure: AllocateAndMapSharedMemory failed

As you can see, there are lots of lines of this:

Jul 16 00:06:09 gabriel-Latitude-7490 gnome-shell[503208]: [503636:1:0100/000000.711106:ERROR:broker_posix.cc(46)] Received unexpected number of handles
Jul 16 00:06:09 gabriel-Latitude-7490 gnome-shell[503208]: [503636:1:0100/000000.711119:ERROR:command_buffer_proxy_impl.cc(96)] ContextResult::kFatalFailure: AllocateAndMapSharedMemory failed

Why?

I then ran:

head -n 100000 /var/log/syslog > ~/sysloghead.txt

which created a 17.2 MB file I could open in a text editor like Sublime Text. Scanning the file shows that it was writing 17783 lines per second! The 2 lines above are 344 bytes + newlines = 346 bytes, so that equates to 17783/2*346 = 3076459 bytes/sec = 3.076459 MB/sec.

20 GB = 20000 MB / 3.076459 Mb/sec = 6500 sec / 3600 sec/hr = 1.8 hrs. It would take 1.8 hrs to use up my 20 GB I freed, at that rate.

So, what's going on? What is this error? Is this what filled up my disk space suddenly or is it possible I have a virus or something? To my knowledge, I've never had a virus in Linux before and I've been using Ubuntu as my primary OS at both home and work since 2018.

I need my space back. Can I delete /var/log/syslog to free up 44 GB of space?

I'm not sure if this is a gnome-shell bug or not, but I just reported it here: https://gitlab.gnome.org/GNOME/gnome-shell/-/issues/5662

Gabriel Staples
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    got the same today on ubuntu 22.04, my rate was 15893 lines/s :/ – mbernasocchi Jul 21 '22 at 06:56
  • @mbernasocchi, interesting. I'm surprised more people are seeing it. Any idea what triggered it? I had recently disabled hardware acceleration in Chrome and restarted Chrome due to conflicts of that with Google Meet. You? – Gabriel Staples Jul 21 '22 at 07:38
  • @mbernasocchi, Be sure to leave a comment on the Chrome bug report by the way so they can see it's affecting more people. See the bottom of my answer for the link. – Gabriel Staples Jul 21 '22 at 07:38
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    I already did that. no idea what triggered it. – mbernasocchi Jul 22 '22 at 08:05

1 Answers1

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Update: This bug has been fixed on Tue Jul 26 20:37:31 2022. See this comment response to my bug report here and this commit here: c565dd300a910b199ddef6ea83dcf4a3414525bf. Please update your Chromium-based browser.

First, I rebooted to kill and restart the process that was logging like crazy.

Next, I don't know if this is bad or not, but I just truncated my syslog file to 1 GB to free up 43 GB of space, like this:

sudo truncate -s 1G /var/log/syslog

I really need that free space.

Source: I cannot clear syslog but I can remove it?

I also reported the log messages from gnome-shell as a possible bug here: https://gitlab.gnome.org/GNOME/gnome-shell/-/issues/5662

It turns out they are Chrome errors, however, not gnome-shell errors. They only show up as gnome-shell apparently because gnome-shell is what launched Chrome. See the actual source code which printed the errors here:

  1. Line 46: https://chromium.googlesource.com/chromium/src/+/HEAD/mojo/core/broker_posix.cc#46
  2. Lines 96-97: https://chromium.googlesource.com/chromium/src/gpu/+/master/ipc/client/command_buffer_proxy_impl.cc#96

I just reported this issue to the Google Chromium team: Issue 1345116: broker_posix.cc:46 and command_buffer_proxy_impl.cc:96 log up to 17783 lines per second, filling up whole disk in hours!

And I sent this to the Google Chrome team via: click 3 dots in the top-right corner of the Chrome browser --> Help --> Report an Issue...:

Chromium log lines at broker_posix.cc line 46 and command_buffer_proxy_impl.cc line 96 log up to 17783 lines per second, filling up whole disk in hours! Please throttle the logging. See: https://bugs.chromium.org/p/chromium/issues/detail?id=1345116

Gabriel Staples
  • 9,155