Re: [PATCH] mtd: mtdoops: mtdoops works with kexec correctly

From: KOSAKI Motohiro
Date: Mon Dec 21 2009 - 19:03:15 EST


> On Mon, 21 Dec 2009 19:20:35 +0900 (JST)
> KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx> wrote:
>
> > commit 2e386e4ba(mtdoops: refactor as a kmsg_dumper) is very good patch.
> > but unfortunately it doesn't works with kexec and few embedded user need
> > to use kexec. there is no reason to don't implement it. it isn't so
> > hard.
> >
> > FAQ
> > ---
> > Q. Why KMSG_DUMP_OOPS is insufficient?
> > A. Because crash_kexec() is called before KMSG_DUMP_OOPS if
> > panic_on_oops==1.
> >
> > Q. Why do you move KMSG_DUMP_PANIC call place?
> > A. Otherwise kmsg_dump() is called twice if kexec enabled.
> > it's annoy.
>
> I think it would be better to describe these comments in text instead
> of as FAQs. Because of the --- it's also removed from the git log.
> Maybe something like
>
> kmsg_dump: Dump on crash_kexec as well
>
> crash_kexec gets called before kmsg_dump(KMSG_DUMP_OOPS) if
> panic_on_oops is set, so the kernel log buffer is not stored
> for this case.
>
> This patch adds a KMSG_DUMP_KEXEC dump type which gets called
> when crash_kexec() is invoked. To avoid getting double dumps,
> the old KMSG_DUMP_PANIC is moved below crash_kexec(). The
> mtdoops driver is modified to handle KMSG_DUMP_KEXEC in the
> same way as a panic.
>
>
> Other than that, it looks fine to me. I've done basic testing against
> 2.6.33-rc1, but unfortunately without kexec support.
>
> Acked-by: Simon Kagstrom <simon.kagstrom@xxxxxxxxxxxxxx>

Thanks. Your description is obviously better.



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