On 2024-01-10 00:34:48 +0100, Ludovic Courtès wrote: > Tomas Volf <~@wolfsden.cz> skribis: > > > On 2024-01-07 15:08:59 +0100, Ludovic Courtès wrote: > > [...] > > >> ** Do not accidentally wait for Linux kernel thread completion > >> (<https://issues.guix.gnu.org/67132>) > >> > >> In cases a PID file contained a bogus PID or one that’s only valid in a > >> separate PID namespace, shepherd could end up waiting for the > >> termination of > >> what’s actually a Linux kernel thread, such as PID 2 (“kthreadd”). This > >> situation is now recognized and avoided. > > > > This is great, I will not have to remember to run `modprobe -r mt7921e' > > before > > each shutdown anymore. I hope. Looking forward to getting it in the Guix > > :) > > D’oh, why did you have to do that?
Otherwise the shepherd would be stuck on shutdown waiting for process named
[mt76-tx phy0]
to terminate with messages along the lines of:
shepherd[1]: waiting for process termination (processes left: (1 678))
It is a kernel thread as far as I can tell (based on
https://stackoverflow.com/a/12231039):
$ cd /proc/678
$ cat cmdline
$ readlink exe; echo $?
1
Removing the module mt7921e stops the thread, so shepherd does not wait for it.
> How did Shepherd end up with “wrong” PID?
That I do not know. It is visible in `ps' output, so I assume shepherd picked
it up on its own somehow.
>
> I hope this release fixes it!
As far as I can tell, the 0.10.3 was already added into guix:
$ ps 1 | cat
PID TTY STAT TIME COMMAND
1 ? Sl 0:01
/gnu/store/bhynhk0c6ssq3fqqc59fvhxjzwywsjbb-guile-3.0.9/bin/guile
--no-auto-compile
/gnu/store/06mz0yjkghi7r6d7lmhvv7gryipljhdd-shepherd-0.10.3/bin/shepherd
--config /gnu/store/klkqq2y65k141rlipq4ls0w2rlhds12h-shepherd.conf
So I have to say it sadly did not resolve this issue. I am unsure why though.
I am not familiar with Shepherd's code base, but quick look at the git log
suggested that procedure (@@ (shepherd service) pseudo-process?) is the relevant
one. When I try it from a REPL, it returns #t.
$ guix shell guile shepherd guile-fibers -- guile
GNU Guile 3.0.9
Copyright (C) 1995-2023 Free Software Foundation, Inc.
Guile comes with ABSOLUTELY NO WARRANTY; for details type `,show w'.
This program is free software, and you are welcome to redistribute it
under certain conditions; type `,show c' for details.
Enter `,help' for help.
scheme@(guile-user)> ,use (shepherd service)
scheme@(guile-user)> ((@@ (shepherd service) pseudo-process?) 688)
$1 = #t
So it *should* work? However the issue is caused by non-free WiFi driver on a
corrupted kernel, so I am not sure if it is even problem that needs to be
solved... I would (obviously) like to see it resolved, but I probably cannot
even bug report it, since it requires non-free hardware and software to
reproduce.
Tomas
PS: It is interesting that `guix shell guile shepherd' is not enough, the
guile-fibers have to be explicitly specified as well. Is that expected?
--
There are only two hard things in Computer Science:
cache invalidation, naming things and off-by-one errors.
signature.asc
Description: PGP signature
