Bug#918764: udev: "udevadm control --reload-rules" kills all processes except init

[Axel Beckert]

Control: reopen -1
Control: found -1 240-3

Hi Michael,

Michael Biebl wrote:
> > I luckily can no more reproduce this with udev 240-3 and kernel
> > 4.19.13-1 or 4.20-1~exp1.
> 
> Ok, thanks for testing.

*sigh* I'm sorry to say, but it just happened again with udev 240-3
and kernel 4.20-1~exp1.

> > Since I can no more reproduce this with the versions above and I'm
> > also affected by (parts of) #918590 which make every reboot taking
> > about 8 to 9 minutes due to waiting for LVM (
> 
> If I would have to guess, I'd say it's another instance of
> https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=908796
> 
> You could try to add a sleep 5 at around line 179 in /etc/init.d/udev
> right before the udevadm calls.

Did that. And since the grub update (which calls LVM commands en
masse) took ages, I thought that I can maybe speed that up by
restarting udev with the modified init script:

"service udev restart" clearly didn't call "sleep 5", exited
successfully within a second or so.

So I did a "service udev stop" and a few seconds later a "service udev
start". After that 5 seconds of nothing, I got about a dozen lines of
warnings (something about mtp devices with I/O errors, maybe related
to my USB card reader without cards in it) and then was suddenly back
on my console login's getty.

Afterwards only init and the gettys were running.

Not sure if the still running grub package configuration triggered it
or part of the udev init script.

Another "service udev stop" and "service udev start" though didn't
trigger the issue again. Will try "udevadm control --reload-rules"
once grub is finished updating and then will reboot, see if that
changes anything (startup delays or process killings) and report more
details.

		Regards, Axel
-- 
 ,''`.  |  Axel Beckert <abe at debian.org>, https://people.debian.org/~abe/
: :' :  |  Debian Developer, ftp.ch.debian.org Admin
`. `'   |  4096R: 2517 B724 C5F6 CA99 5329  6E61 2FF9 CD59 6126 16B5
  `-    |  1024D: F067 EA27 26B9 C3FC 1486  202E C09E 1D89 9593 0EDE