Bug#1103152: Starts 2nd getty on hvc0, making console login (almost) impossible

From	Lorenzo <plorenzo@disroot.org>
Newsgroups	linux.debian.bugs.rc
Subject	Bug#1103152: Starts 2nd getty on hvc0, making console login (almost) impossible
Date	2025-04-17 00:30 +0200
Message-ID	<KCjqx-e2kV-3@gated-at.bofh.it> (permalink)
References	<KBt8C-dtFy-11@gated-at.bofh.it> <KCc5H-dXz8-3@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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Hi Andras,

On Wed, 16 Apr 2025 16:26:00 +0200 Andras Korn
<korn-debbugs@elan.rulez.org> wrote:
> On Wed, Apr 16, 2025 at 12:50:13AM +0200, Lorenzo wrote:
> 
> > > This system doesn't have a /dev/ttyS0, but that doesn't stop the
> > > getty-ttyS0 service from doing this:
> > > 
> > > --- 8< ---
> > 
> > [snip]
> > 
> > > fi
> > > + pgrep -x agetty -t hvc0
> > > + pgrep -x fgetty -t hvc0
> > > 
> > [snip]
> 
> Ah, right. It didn't catch my getty, because it's neither agetty nor
> fgetty but plain getty:
> 
> root      1979  0.0  0.0   2344   160 ?        Ss    2023   0:21  \_
> runsv getty-hvc0 root     18185  0.0  0.0   2660   944 ?        S
> Apr14   0:00  |   \_ /sbin/getty 38400 hvc0
> 
> And also because getty's controlling tty isn't /dev/hvc0; it uses
> (has an FD open for) that character device, but it's not its ctty:

does your test with fuser work?

something like
'fuser /dev/hvc0'

I don't have a VPS with hvc0 (Xen?) but I did some testing:

pgrep seems to work for physical hardware systems but it fails in
qemu and in docker (but only if unprivileged), while fuser seems to work
in all cases that I was able to test..

> I still think the best would be not to install this service by
> default, because making it robust enough would make it too complex.
ok but, for several reasons, after Trixie release. Meanwhile it's better
to fix this in some way, even if not perfect. Otherwise I'll have to
downgrade the severity and put it on hold.

Let me know,
Lorenzo

Thread

Bug#1103152: Starts 2nd getty on hvc0, making console login (almost) impossible Andras Korn <korn-debbugs@elan.rulez.org> - 2025-04-14 16:40 +0200
  Processed: Re: Bug#1103152: Starts 2nd getty on hvc0, making  console login (almost) impossible "Debian Bug Tracking System" <owner@bugs.debian.org> - 2025-04-16 01:00 +0200
  Processed: Re: Bug#1103152: Starts 2nd getty on hvc0, making  console login (almost) impossible "Debian Bug Tracking System" <owner@bugs.debian.org> - 2025-04-16 01:00 +0200
  Bug#1103152: Starts 2nd getty on hvc0, making console login (almost) impossible Lorenzo <plorenzo@disroot.org> - 2025-04-16 11:10 +0200
  Processed: Re: Bug#1103152: Starts 2nd getty on hvc0, making  console login (almost) impossible "Debian Bug Tracking System" <owner@bugs.debian.org> - 2025-04-16 11:10 +0200
  Bug#1103152: Starts 2nd getty on hvc0, making console login (almost) impossible Andras Korn <korn-debbugs@elan.rulez.org> - 2025-04-16 16:40 +0200
    Bug#1103152: Starts 2nd getty on hvc0, making console login  (almost) impossible Lorenzo <plorenzo@disroot.org> - 2025-04-17 00:30 +0200
  Bug#1103152: Starts 2nd getty on hvc0, making console login (almost) impossible Andras Korn <korn-debbugs@elan.rulez.org> - 2025-04-22 10:20 +0200
  Processed: Re: Bug#1103152: Starts 2nd getty on hvc0, making  console login  (almost) impossible "Debian Bug Tracking System" <owner@bugs.debian.org> - 2025-04-26 19:30 +0200
  Bug#1103152: marked as pending in runit Lorenzo Puliti <noreply@salsa.debian.org> - 2025-04-27 00:50 +0200
  Processed: Bug#1103152 marked as pending in runit "Debian Bug Tracking System" <owner@bugs.debian.org> - 2025-04-27 00:50 +0200
  Bug#1103152: marked as done (Starts 2nd getty on hvc0, making  console login (almost) impossible) "Debian Bug Tracking System" <owner@bugs.debian.org> - 2025-04-30 10:00 +0200

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