Re: [PATCH v4 0/2] kexec, panic: Making crash_kexec() NMI safe

Baoquan He
2022-07-12T02:47:59Z

Hi,

On 06/30/22 at 11:32pm, Valentin Schneider wrote:
> Hi folks,
>
> Here's ~v3~ v4 where we now completely get rid of kexec_mutex.
>
> o Patch 1 makes sure all kexec_mutex acquisitions are trylocks. This prevents
> having to add any while(atomic_cmpxchg()) loops which I'd really hate to see
> here. If that can't be done then I think we're better off with the combined
> mutex+atomic var approach.
> o Patch 2 does the mutex -> atomic var switch.

This series looks good, has it been taken into any tree?

Thanks
Baoquan

>
> Revisions
> =========
>
> v3 -> v4
> ++++++++
>
> o Someone forgot to Cc LKML on v3...
>
> v2 -> v3
> ++++++++
>
> o Dropped kexec_mutex entirely and made the atomic variable the one true lock
> for kexec (Eric)
>
> v1 -> v2
> ++++++++
>
> o Changed from Peterson-like synchronization to simpler atomic_cmpxchg
> (Petr)
> o Slightly reworded changelog
> o Added Fixes: tag. Technically should be up to since kexec can happen
> in an NMI, but that isn't such a clear target
>
> Cheers,
> Valentin
>
> Valentin Schneider (2):
> kexec: Turn all kexec_mutex acquisitions into trylocks
> panic, kexec: Make __crash_kexec() NMI safe
>
> include/linux/kexec.h | 2 +-
> kernel/kexec.c | 11 ++++-------
> kernel/kexec_core.c | 28 ++++++++++++++++------------
> kernel/kexec_file.c | 4 ++--
> kernel/kexec_internal.h | 15 ++++++++++++++-
> kernel/ksysfs.c | 7 ++++++-
> 6 files changed, 43 insertions(+), 24 deletions(-)
>
> --
> 2.31.1
>