Re: [PATCH] MIPS: math-emu: Write-protect delay slot emulation pages

[Sasha Levin]

On Fri, Dec 21, 2018 at 09:16:37PM +0000, Paul Burton wrote:
> Hi Sasha,
>
> On Thu, Dec 20, 2018 at 07:26:15PM +0000, Sasha Levin wrote:
> > Hi,
> >
> > [This is an automated email]
> >
> > This commit has been processed because it contains a "Fixes:" tag,
> > fixing commit: 432c6bacbd0c MIPS: Use per-mm page to execute branch delay slot instructions.
> >
> > The bot has tested the following trees: v4.19.10, v4.14.89, v4.9.146,
>
> Neat! I like the idea of this automation :)

Thank you! :)

> > v4.19.10: Build OK!
> > v4.14.89: Build OK!
> > v4.9.146: Failed to apply! Possible dependencies:
> >     05ce77249d50 ("userfaultfd: non-cooperative: add madvise() event for MADV_DONTNEED request")
> >     163e11bc4f6e ("userfaultfd: hugetlbfs: UFFD_FEATURE_MISSING_HUGETLBFS")
> >     67dece7d4c58 ("x86/vdso: Set vDSO pointer only after success")
> >     72f87654c696 ("userfaultfd: non-cooperative: add mremap() event")
> >     893e26e61d04 ("userfaultfd: non-cooperative: Add fork() event")
> >     897ab3e0c49e ("userfaultfd: non-cooperative: add event for memory unmaps")
> >     9cd75c3cd4c3 ("userfaultfd: non-cooperative: add ability to report non-PF events from uffd descriptor")
> >     d811914d8757 ("userfaultfd: non-cooperative: rename *EVENT_MADVDONTNEED to *EVENT_REMOVE")
>
> This list includes the correct soft dependency - commit 897ab3e0c49e
> ("userfaultfd: non-cooperative: add event for memory unmaps") which
> added an extra argument to mmap_region().
>
> > How should we proceed with this patch?
>
> The backport to v4.9 should simply drop the last argument (NULL) in the
> call to mmap_region().
>
> Is there some way I can indicate this sort of thing in future patches so
> that the automation can spot that I already know it won't apply cleanly
> to a particular range of kernel versions? Or even better, that I could
> indicate what needs to be changed when backporting to those kernel
> versions?

The "official" way of doing that is described here:

	https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/stable-kernel-rules.rst#n101

However, most people just either add a comment in the commit message, or
reply to the patch mail (or the "FAILED:" mail from Greg) saying how to
fix this. Either way works really.

Greg will also usually look up these automated mails when he adds stuff
to -stable, so if you describe how to deal with it here (like you did
above) is enough as well.

--
Thanks,
Sasha