linux-kernel - Re: [PATCH v3 0/2] cpuhp: fix some st->target issues

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Date:   Wed, 10 Aug 2022 10:45:18 -0400
From:   Phil Auld <pauld@...hat.com>
To:     linux-kernel@...r.kernel.org
Cc:     Thomas Gleixner <tglx@...utronix.de>,
        Peter Zijlstra <peterz@...radead.org>,
        Valentin Schneider <vschneid@...hat.com>
Subject: Re: [PATCH v3 0/2] cpuhp: fix some st->target issues

On Mon, Jul 11, 2022 at 05:16:17PM -0400 Phil Auld wrote:
> Several small fixes that clean up some cpuhp inconsistencies.
> The first prevents target_store() from calling cpu_down() when
> target == state which prevents the cpu being incorrectly marked
> as dying.  The second just makes the boot cpu have a valid cpuhp
> target rather than 0 (CPU_OFFLINE) while being in state
> CPU_ONLINE.
> 
> A further issue which these two patches don't address is that
> the cpuX/online file looks at the device->offline state and can
> thus get out of sync with the actual cpuhp state if the cpuhp
> target is used to change state.
> 
> v3: Added code to make sure st->target == target in the nop case.
> 
> Phil Auld (2):
>   cpuhp: make target_store() a nop when target == state
>   cpuhp: Set cpuhp target for boot cpu
> 
>  kernel/cpu.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> -- 
> 2.31.1
> 

Ping?

Any thoughts on this? I'm not sure what tree it needs to go in but
getting a cpu shutdown by writing the current target/state back
in here seems wrong.


Thanks,
Phil

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