Messages in this thread | | | Date | Tue, 20 Jun 2023 11:01:57 +0200 | From | Borislav Petkov <> | Subject | Re: [patch v3 4/7] x86/smp: Use dedicated cache-line for mwait_play_dead() |
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On Thu, Jun 15, 2023 at 10:33:55PM +0200, Thomas Gleixner wrote: > Monitoring idletask::thread_info::flags in mwait_play_dead() has been an > obvious choice as all what is needed is a cache line which is not written > by other CPUs. > > But there is a use case where a "dead" CPU needs to be brought out of that > mwait(): kexec().
s/mwait()/wait state/
I guess.
> The CPU needs to be brought out of mwait before kexec() as kexec() can
Ditto.
> overwrite text, pagetables, stacks and the monitored cacheline of the > original kernel.
Yikes.
> The latter causes mwait to resume execution which > obviously causes havoc on the kexec kernel which results usually in triple > faults.
This sounds like a stable fix, no?
Reviewed-by: Borislav Petkov (AMD) <bp@alien8.de>
-- Regards/Gruss, Boris.
https://people.kernel.org/tglx/notes-about-netiquette
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