[regression] some Dell systems hang at shutdown due to "x86/smp: Put CPUs into INIT on shutdown if possible" (was Fwd: Kernel 6.5 hangs on shutdown)

[Linux regression tracking (Thorsten Leemhuis)]

[CCing x86 maintainers]

Hi Thomas!

On 12.10.23 11:37, Bagas Sanjaya wrote:
> 
> I notice a regression report on Bugzilla [1]. Quoting from it:
>>> I use Dell OptiPlex 7050, and kernel hangs when shutting down the
computer.
>> Similar symptom has been reported on some forums, and all of them are using
>> Dell computers:
>> https://bbs.archlinux.org/viewtopic.php?pid=2124429
>> https://www.reddit.com/r/openSUSE/comments/16qq99b/tumbleweed_shutdown_did_not_finish_completely/
>> https://forum.artixlinux.org/index.php/topic,5997.0.html

Another report: https://bugzilla.redhat.com/show_bug.cgi?id=2241279

>From all those links it seems quite a lot of users with Dell machines
are affected by this problem.

>> Tested with various kernel and this bug seems to be caused by commit: 88afbb21d4b36fee6acaa167641f9f0fc122f01b.

Thomas, turns out that bisection result was slightly wrong: a recheck
confirmed that the regression is actually caused by 45e34c8af58f23
("x86/smp: Put CPUs into INIT on shutdown if possible") [v6.5-rc1] of
yours. See https://bugzilla.kernel.org/show_bug.cgi?id=217995 for details.

Ciao, Thorsten

> Anyway, I'm adding this regression to be tracked by regzbot:
> [...]

#regzbot introduced: 45e34c8af58f
#regzbot link: https://bugzilla.redhat.com/show_bug.cgi?id=2241279