Dear Maintainer,

After extended use (several hours, heavy workload), the system fails
to complete shutdown. On one occasion I was able to see the console
output before the screen went dark: the system was stuck at
"session-2.scope/stop running" with a 1min30s timeout, hanging around
the 54s mark. After the timeout expires the screen goes dark and the
keyboard backlight stays on, but the machine never actually powers
off — no fan activity, power button LED remains lit. Only a forced
power-off (holding the power button ~10-15s) recovers the machine.
REISUB does not respond at this stage.

This does NOT happen when shutting down after only light/brief use
with the same kernel — the issue appears tied to extended uptime
under load, not to every shutdown.

I bisected this across three kernels on the same hardware/session
pattern (extended workload before shutdown):

- linux-image-6.12.96+deb13-amd64: shuts down cleanly, no issue,
  including after a full heavy workday.
- linux-image-7.0.13+deb13-amd64: shuts down cleanly, no issue,
  including after ~3/4 of a heavy workday.
- linux-image-7.1.3+deb13-amd64: fails to complete shutdown after
  extended use; reproduced on separate occasions.

Hardware: Clevo V560EU laptop.

The session-2.scope stop timeout suggests a user session process
is not terminating cleanly on SIGTERM, possibly related to GPU
state, PipeWire/audio, or another long-running session service that
only develops this state after extended uptime. I suspect a
regression introduced between 7.0.13 and 7.1.3.

I'm available to test patches or provide further logs if useful.