Very similar thing happened on Lubuntu 20.04, `apt-get dist-upgrade` said Unpacking snapd (2.47.1+20.04) over (2.46.1+20.04) ... Setting up snapd (2.47.1+20.04) ... Installing new version of config file /etc/apparmor.d/usr.lib.snapd.snap-confine.real ...
and hung. `pstree` just showed `apt-get---dpkg---snapd.postinst` (no children). It ignored `SIGINT` and `SIGTERM`. `ps auxwww` shows root 4091 0.0 0.0 2608 1740 pts/1 S+ 09:42 0:00 /bin/sh /var/lib/dpkg/info/snapd.postinst configure 2.46.1+20.04 and `ls -l /proc/4091/fd` gives lrwx------ 1 root root 64 Nov 3 11:43 0 -> /dev/pts/1 l-wx------ 1 root root 64 Nov 3 11:44 1 -> /dev/null lr-x------ 1 root root 64 Nov 3 11:44 10 -> /var/lib/dpkg/info/snapd.postinst lrwx------ 1 root root 64 Nov 3 11:44 11 -> /dev/pts/1 lrwx------ 1 root root 64 Nov 3 11:44 2 -> /dev/pts/1 (timestamps being the current time of the `ls`, not the process start time which was about 2 hours earlier) I was connecting to the machine via `ssh` from elsewhere on our home network. After `kill -9 4091` the parent `dpkg` process was still hung, `ps auxwww` gives: root 4090 0.0 0.2 18092 9932 pts/1 Ss+ 09:42 0:00 /usr/bin/dpkg --status-fd 55 --configure --pending and `ls -l /proc/4090/fd` gives: lrwx------ 1 root root 64 Nov 3 11:49 0 -> /dev/pts/1 lrwx------ 1 root root 64 Nov 3 11:49 1 -> /dev/pts/1 lrwx------ 1 root root 64 Nov 3 11:49 2 -> /dev/pts/1 lrwx------ 1 root root 64 Nov 3 11:49 3 -> /var/lib/dpkg/lock l-wx------ 1 root root 64 Nov 3 11:49 4 -> /var/lib/dpkg/updates/tmp.i lrwx------ 1 root root 64 Nov 3 11:49 5 -> /var/lib/dpkg/triggers/Lock l-wx------ 1 root root 64 Nov 3 11:49 55 -> 'pipe:[55607]' lr-x------ 1 root root 64 Nov 3 11:49 6 -> /var/lib/dpkg/triggers/Unincorp l-wx------ 1 root root 64 Nov 3 11:49 7 -> /var/log/dpkg.log lr-x------ 1 root root 64 Nov 3 11:49 8 -> /var/lib/dpkg/diversions After `kill -9 4090` the original SSH session gets E: Sub-process /usr/bin/dpkg exited unexpectedly W: Operation was interrupted before it could finish and dropped back to root prompt. I then tried `dpkg --configure -a` and it apparently went straight through: Setting up snapd (2.47.1+20.04) ... snapd.failure.service is a disabled or a static unit, not starting it. snapd.snap-repair.service is a disabled or a static unit, not starting it. and then carried on setting up the other packages. So I'm logging the above in the hope that somebody can read more meaning into it than I can. -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to systemd in Ubuntu. https://bugs.launchpad.net/bugs/1868706 Title: Snapd postinst script hangs Status in snapd: Triaged Status in dpkg package in Ubuntu: Invalid Status in systemd package in Ubuntu: Invalid Bug description: On a machine which has been tracking upgrades for a while, I am unable to install new versions of snapd. The install process stalls indefinitely. Processes running suggest this is a hang in the postinst: ~$ ps ax | grep dpkg 2388 pts/1 Ss+ 0:00 /usr/bin/dpkg --status-fd 25 --configure --pending 2389 pts/1 S+ 0:00 /bin/sh /var/lib/dpkg/info/snapd.postinst configure 2.43.3+git1.8109f8 2875 pts/2 S+ 0:00 grep --color=auto dpkg ~$ pstree 2388 dpkg───snapd.postinst───systemctl───systemd-tty-ask ~$ ps ax | grep snapd 732 ? Ssl 0:00 /usr/lib/snapd/snapd 2389 pts/1 S+ 0:00 /bin/sh /var/lib/dpkg/info/snapd.postinst configure 2.43.3+git1.8109f8 2452 pts/1 S+ 0:00 /bin/systemctl start snapd.autoimport.service snapd.core-fixup.service snapd.recovery-chooser-trigger.service snapd.seeded.service snapd.service snapd.snap-repair.timer snapd.socket snapd.system-shutdown.service 2880 pts/2 S+ 0:00 grep --color=auto snapd To manage notifications about this bug go to: https://bugs.launchpad.net/snapd/+bug/1868706/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp