Hibernate stuck after recent kernel/workqueue.c changes in Stable 6.6.23

[Linux regression tracking (Thorsten Leemhuis)]

Hi stable team, there is a report that the recent backport of
5797b1c18919cd ("workqueue: Implement system-wide nr_active enforcement
for unbound workqueues") [from Tejun] to 6.6.y (as 5a70baec2294) broke
hibernate for a user. 6.6.24-rc1 did not fix this problem; reverting the
culprit does.

> With kernel 6.6.23 hibernating usually hangs here: the display stays
> on but the mouse pointer does not move and the keyboard does not work.
> But SysRq REISUB does reboot. Sometimes it seems to hibernate: the
> computer powers down and can be waked up and the previous display comes
> visible, but it is stuck there.

See https://bugzilla.kernel.org/show_bug.cgi?id=218658 for details.
Note, you have to use bugzilla to reach the reporter, as I sadly[1] can
not CCed them in mails like this.

Side note: there is a mainline report about problems due to
5797b1c18919cd ("workqueue: Implement system-wide nr_active enforcement
for unbound workqueues") as well, but it's about "nohz_full=0 prevents
kernel from booting":
https://bugzilla.kernel.org/show_bug.cgi?id=218665; will forward that
separately to Tejun.

Ciao, Thorsten (wearing his 'the Linux kernel's regression tracker' hat)
--
Everything you wanna know about Linux kernel regression tracking:
https://linux-regtracking.leemhuis.info/about/#tldr
If I did something stupid, please tell me, as explained on that page.

[1] because bugzilla.kernel.org tells users upon registration their
"email address will never be displayed to logged out users"

#regzbot introduced: 5a70baec2294e8a7d0fcc4558741c23e752dad
#regzbot from: Petri Kaukasoina
#regzbot duplicate: https://bugzilla.kernel.org/show_bug.cgi?id=218658
#regzbot title: workqueue: hubernate usually hangs when going to sleep
#regzbot ignore-activity