How do I clear a lock so as to allow an upgrade

[J. Paul Bissonnette]

On Sun, 13 Nov 2022 08:25:06 +0800
bret at busby.net wrote:

> On 13/11/2022 08:15, Bret Busby wrote:
> > On 13/11/2022 07:59, Bret Busby wrote:
> >> On 13/11/2022 07:53, J. Paul Bissonnette wrote:
> >>> Is another program like synaptic running?
> >>>
> >>> On Sun, 13 Nov 2022 07:50:19 +0800
> >>> bret at busby.net wrote:
> >>>
> >>>> Hello.
> >>>>
> >>>> Having run
> >>>> sudo apt update
> >>>> when I try to run
> >>>> sudo apt full-upgrade -y
> >>>> I get the following error.
> >>>>
> >>>> "
> >>>> Sun Nov 13 07:33:46 bret at bret-OptiPlex-9030-AIO:~$sudo apt
> >>>> full-upgrade -y Waiting for cache lock: Could not get lock
> >>>> /var/lib/dpkg/lock-frontend. It is held by process 48429 (apt)
> >>>> Waiting for cache lock: Could not get lock
> >>>> /var/lib/dpkg/lock-frontend. It is held by process 48429 (apt)
> >>>> Waiting for cache lock: Could not get lock
> >>>> /var/lib/dpkg/lock-frontend. It is held by process 48429 (apt)
> >>>> Waiting for cache lock: Could not get lock
> >>>> /var/lib/dpkg/lock-frontend. It is held by process 48429 (apt)
> >>>> Waiting for cache lock: Could not get lock
> >>>> /var/lib/dpkg/lock-frontend. It is held by process 48429 (apt)
> >>>> Waiting for cache lock: Could not get lock
> >>>> /var/lib/dpkg/lock-frontend. It is held by process 48429 (apt)
> >>>> ^Citing for cache lock: Could not get lock
> >>>> /var/lib/dpkg/lock-frontend. It is held by process 48429
> >>>> (apt)... 6s Sun Nov 13 07:34:28 bret at bret-OptiPlex-9030-AIO:~$^C
> >>>> "
> >>>>
> >>>> How do I clear the lock, so as to allow the upgrade to proceed?
> >>>>
> >>>> I have run
> >>>> sudo kill 48429
> >>>> and that did not fix the problem, and I have rebooted the
> >>>> system, and that did not clear the lock.
> >>>>
> >>>> Also,
> >>>>
> >>>> "
> >>>> Sun Nov 13 07:44:11 bret at bret-OptiPlex-9030-AIO:~$sudo kill -9
> >>>> 48429 Sun Nov 13 07:44:23 bret at bret-OptiPlex-9030-AIO:~$ps -ax |
> >>>> grep 48429 48429 pts/1    Z      0:00 [apt] <defunct>
> >>>>    248169 pts/3    S+     0:00 grep --color=auto 48429
> >>>> Sun Nov 13 07:44:28 bret at bret-OptiPlex-9030-AIO:~$
> >>>> "
> >>>>
> >>>> I assume that the 'Z' means zombie, as it is one of the undead,
> >>>> and cannot be killed (I understand that kill -9 is the
> >>>> penultimate kill command; the kill of last resort, like a nuke).
> >>>>
> >>>> So, apart from reinstalling the system, to get to do an upgrade,
> >>>> how do I clear the lock?
> >>>>
> >>>> Thank you in anticipation.
> >>>> ..
> >>>> Bret Busby
> >>>> Armadale
> >>>> Western Australia
> >>>> (UTC+0800)
> >>>> .................
> >>>>
> >>>>
> >>>
> >>>
> >>
> >> Not synaptic.
> >>
> >> The only other possible running program, is that the System Update 
> >> applet shows that updates are available, but, the same pid applies 
> >> after rebooting and not manually loading any program, other than
> >> the sudo update
> >> and then sudo full upgrade
> >> .
> >>
> >> So, the lock and the pid are both preserved, regardless of what 
> >> happens, and, through a shutdown and reboot (shutdown -r)
> >>
> > 
> > I should maybe have explicitly clarified this; I reboot the system,
> > and then do not load any program, but run
> > sudo apt update
> > and then run (or, try to run)
> > sudo apt full upgrade -y
> > and the lock error occurs.
> > 
> > I assume that the only other possible application running, that
> > involves package management, is the Software Updater applet, which
> > shows that updates are available.
> > 
> > I have tried running the update and the upgrade commands on
> > separate lines, as above, as, as I usually run them in a
> > combination command (sudo apt update -y && sudo apt full-upgrade -y
> > && sudo apt autoremove -y && sudo apt autoclean -y)
> > , I had initially assumed that the upgrade command was trying to be
> > run, before the update command had completed, thence, the lock
> > problem. But, that assumption is apparently proved wrong.
> > 
> > 
> The other observation that I should have included, in my more
> explicit clarification, is that the lock process is shown to persist
> through the system reboots, as, in addition to the 'Z' for zombie
> flag, the same pid persists through the reboots, so that, even if I
> open and then close the Software Updater, before running the two apt
> commands, which should increment the available pid's, before running
> the apt commands, the lock pid remains the same, thus showing that it
> is resurrected each time the system boots, and, will persist until t
> is erased.
> 
> ..
> Bret Busby
> Armadale
> West Australia
> (UTC+0800)
> ..............
> 
> 

What happens if you use the system monitor to kill the process?