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