Alex's questions

Lubuntu 18.04.1 running flawlessly in VirtualBox for about two years, had a few updates to install yesterday.

After the updates both firefox and chromium cannot start. When launching them from the terminal they just throw the error Segmentation fault (core dumped) .

syslog shows this:

[ 1117.595260] firefox[1589]: segfault at 1 ip 0000000000000001 sp 00007ffc7be98758 error 14 in firefox[7faebfd8f000+9a000]
[ 1117.595270] Code: Bad RIP value.
[ 1125.775419] chromium-browse[1592]: segfault at 2 ip 000056265394fb3c sp 00007ffe209f7608 error 4 in chromium-browser[56264fa77000+9618000]
[ 1125.775423] Code: 43 40 48 c7 43 40 00 00 00 00 48 89 45 e0 48 8d 55 e0 4c 89 f7 41 ff d7 48 8b 7d e0 48 c7 45 e0 00 00 00 00 48 85 ff 74 06 48 <8b> 07 ff 50 08 48 8d 7d d0 e8 16 06 52 fd 48 83 c4 18 5b 41 5e 41

The apt logs of yesterday's updates:

Start-Date: 2020-05-17  20:48:59
Commandline: aptdaemon role='role-commit-packages' sender=':1.263'
Install: libnetplan0:amd64 (0.99-0ubuntu3~18.04.1, automatic)
Upgrade: netplan.io:amd64 (0.98-0ubuntu1~18.04.1, 0.99-0ubuntu3~18.04.1), libapt-inst2.0:amd64 (1.6.12, 1.6.12ubuntu0.1), signal-desktop:amd64 (1.33.4, 1.34.1), libsystemd0:amd64 (237-3ubuntu10.39, 237-3ubuntu10.40), libpulsedsp:amd64 (1:11.1-1ubuntu7.5, 1:11.1-1ubuntu7.7), apt:amd64 (1.6.12, 1.6.12ubuntu0.1), pulseaudio:amd64 (1:11.1-1ubuntu7.5, 1:11.1-1ubuntu7.7), udev:amd64 (237-3ubuntu10.39, 237-3ubuntu10.40), libmagic1:amd64 (1:5.32-2ubuntu0.3, 1:5.32-2ubuntu0.4), libapt-pkg5.0:amd64 (1.6.12, 1.6.12ubuntu0.1), libudev1:amd64 (237-3ubuntu10.39, 237-3ubuntu10.40), nplan:amd64 (0.98-0ubuntu1~18.04.1, 0.99-0ubuntu3~18.04.1), libexif12:amd64 (0.6.21-4ubuntu0.1, 0.6.21-4ubuntu0.2), libmagic-mgc:amd64 (1:5.32-2ubuntu0.3, 1:5.32-2ubuntu0.4), libpulse0:amd64 (1:11.1-1ubuntu7.5, 1:11.1-1ubuntu7.7), chromium-browser:amd64 (81.0.4044.122-0ubuntu0.18.04.1, 81.0.4044.138-0ubuntu0.18.04.1), gir1.2-snapd-1:amd64 (1.49-0ubuntu0.18.04.1, 1.49-0ubuntu0.18.04.2), libpulse-mainloop-glib0:amd64 (1:11.1-1ubuntu7.5, 1:11.1-1ubuntu7.7), systemd-sysv:amd64 (237-3ubuntu10.39, 237-3ubuntu10.40), firefox-locale-en:amd64 (76.0+build2-0ubuntu0.18.04.1, 76.0.1+build1-0ubuntu0.18.04.1), chromium-codecs-ffmpeg-extra:amd64 (81.0.4044.122-0ubuntu0.18.04.1, 81.0.4044.138-0ubuntu0.18.04.1), libpam-systemd:amd64 (237-3ubuntu10.39, 237-3ubuntu10.40), systemd:amd64 (237-3ubuntu10.39, 237-3ubuntu10.40), apt-utils:amd64 (1.6.12, 1.6.12ubuntu0.1), iproute2:amd64 (4.15.0-2ubuntu1, 4.15.0-2ubuntu1.1), libnss-systemd:amd64 (237-3ubuntu10.39, 237-3ubuntu10.40), file:amd64 (1:5.32-2ubuntu0.3, 1:5.32-2ubuntu0.4), firefox:amd64 (76.0+build2-0ubuntu0.18.04.1, 76.0.1+build1-0ubuntu0.18.04.1), libsnapd-glib1:amd64 (1.49-0ubuntu0.18.04.1, 1.49-0ubuntu0.18.04.2), libjson-c3:amd64 (0.12.1-1.3, 0.12.1-1.3ubuntu0.2), chromium-browser-l10n:amd64 (81.0.4044.122-0ubuntu0.18.04.1, 81.0.4044.138-0ubuntu0.18.04.1), pulseaudio-utils:amd64 (1:11.1-1ubuntu7.5, 1:11.1-1ubuntu7.7)
End-Date: 2020-05-17  20:49:55

How do I even begin to trace the cause for this segfault? I assume one of the updated packages is to blame but which packages are shared by firefox and chromiun? Can I roll these updates back?

Updated to add:

1. Other applications still launch and run successfully, including Tor Browser, Signal, Sylpheed, AbiWord and others.

2. This is the output of free -h (as requested by @heynnema in the comments):

              total        used        free      shared  buff/cache   available
Mem:           5.8G        290M        4.5G        2.7M        1.0G        5.3G
Swap:          2.0G          0B        2.0G

Sylpheed stores its data by default under ~/Mail and indeed this folder exists and even contains empty subfolders such as inbox, sent, draft etc.

However I cannot find any mail storage files even after downloading 800 messages form my IMAP mailbox. The messages are available offline so it seems they were downloaded successfully.

Any hint as to where I can find the local storage?

While playing around with a fresh installation of 18.04, I've accidentally selected a photo for my user. I couldn't find an undo or cancel or remove option, so now I'm stuck with a photo on the login screen. Is there any way to return to the default faceless gray avatar?

My workaround would be to create a new user, grab a screenshot, cut the default image and use that as my new "photo" but if there's a real removal option I'd love to know about it.

Update: I did not take a photo with the webcam, just selected one of the provided images, so there is no .face file in my home directory.