Subject: Screensaver with only blank does not work after suspend

From: Klaus Ethgen <[email-masked]>
Date: Mon, 1 Jan 2024 17:21:17 +0100

Package: linux-image-6.5.0-2-amd64
Version: 6.5.6-1
Severity: critical
Tags: security

I report that bug here as debian systemd evangelists start to even
reject bug reports that are unrelated to the location of the files just
because you don't commit to there systemd centric world.

So this is the copy of the original report that I did on debian:

It is not fully clear for me, where exactly this bug happens. First I
was thinking about xscreensaver but that package got not updated for
ages. The bug happens with updates from kernel 6.4.0 to 6.5.0.

I use xscreensaver with fvwm3 on my amd laptop. xscreensaver is set up
to only blank the screen.

When I lock the screen and press a key or moving the mouse, everything
is fine. But when I go to suspend too ram after locking and waking up
the laptop, the password dialog gets showed as usual but I can see the
full desktop content with probably sensitive material on in. Although, I
cannot interact with the desktop, it is a security break to reveal the
content without authenticating.

It might be related, when I have a PSI chat window on the screen but on
different desktop, it gets moved to the current one. That definitively
also came with the new kernel.

Additional informations:
The bug continue up to the newest debian kernel linux-image-6.6.8-amd64.
In contrast to my informations above, it is not really clear, what
triggers the bug but it seems to be limited to AMDGPU. But independent
of the model itself as I see that behavior on two different laptops.

-- System Information:
Distributor ID:	Devuan
Description:	Devuan GNU/Linux 6 (excalibur/ceres)
Release:	6
Codename:	excalibur ceres
Architecture: x86_64

Kernel: Linux 6.4.0-4-amd64 (SMP w/16 CPU threads; PREEMPT)
Kernel taint flags: TAINT_OOT_MODULE, TAINT_UNSIGNED_MODULE
Locale: LANG=C, LC_CTYPE=C.UTF-8 (charmap=UTF-8), LANGUAGE not set
Shell: /bin/sh linked to /bin/dash
Init: sysvinit (via /sbin/init)
LSM: AppArmor: enabled

Gru?
   Klaus
-- 
Klaus Ethgen                                       http://www.ethgen.ch/
pub  4096R/4E20AF1C 2011-05-16            Klaus Ethgen <[email-masked]>
Fingerprint: 85D4 CA42 952C 949B 1753  62B3 79D0 B06F 4E20 AF1C

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From: Mark Hindley <[email-masked]>
Date: Wed, 20 Mar 2024 12:29:27 +0000

Control: tags -1 debian moreinfo

Klaus,

Thanks for this.

> because you don't commit to there systemd centric world.

Is this still an issue?

None of the packages concerned here are forked in Devuan. Can you reproduce it
on a Debian system?

Mark

---

From: Klaus Ethgen <[email-masked]>
Date: Wed, 20 Mar 2024 21:45:34 +0100

Hello Mark,

nice to see that bugs are still addressed in Devuan. Many thanks for
that.

> None of the packages concerned here are forked in Devuan. Can you reproduce it

Since the systemd debacle, I have no debian system left and will never
ever install debian again.

As for Devuan, I migrated my most important systems away to gentoo as I
cannot accept usrmerge. Sorry to say that, I was very happy to see
Devuan evolving until that recent debacle.

With that to say, I have no Devuan on desktop left and cannot verify the
bug anymore. I only use Devuan on some servers (until the support
without usrmerge runs out).

(It is not fully true, I still have my work system on Devuan but
downgraded to daedalus.)

Regards
   Klaus