Re: [clear_page] 0ad07c8104 BUG: unable to handle kernel NULL pointer dereference at 0000000000000040

[Fengguang Wu]

On Sun, Feb 19, 2017 at 01:10:47AM +0100, Borislav Petkov wrote:
> Hey Fengguang,
>
> On Sun, Feb 19, 2017 at 07:29:50AM +0800, Fengguang Wu wrote:
> > Good point! I noticed it too while sending out the report. It'll be
> > showed as this in future:
> >
> >        https://github.com/0day-ci/linux/commits/Borislav-Petkov/x86-Optimize-clear_page/20170210-053052
>
> How about pointing to the patch directly?
>
> https://github.com/0day-ci/linux/commit/0ad07c8104eb5c12dfcb86581c1cc657183496cc

Yes if we add it as a line below the branch URL, it could be a time saver.

> > Sorry the 2nd report was send out manually and I only checked the
> > emails in my _current_ mbox. Since the previous report email has been
> > archived, it slipped through the duplication check.
>
> No worries - this was all a prelude to me hinting at the email-based
> talking to the bot :-)
>
> > CC Xiaolong. It's possible to automate the test-of-fixup-patches.
> > Firstly find out the original email report by the Message-ID being
> > replied to. Then fetch all the information required for deciding where
> > the patch should be applied to, parameters to auto-testing the patch.
>
> Sounds like a plan.
>
> It would probably even be easier for the bot if the reply-mail contained
> specially-formatted hints like:
>
> TEST-WITH-BELOW-PATCH: ...
>
> or so.

Since it's hard to teach ALL people about the rule, it'd be best if we
can work w/o any rules -- unless you want to be accurate&helpful or to
customize test behaviors.

Since we already tested the original patch/commit (hence the report),
we should know where the fixup should be applied to. And it'd be
reasonably easy to tell whether the fix is incremental or a
replacement -- just try git-am onto the original commit first, if
failed, continue to try the parent commit. For old bugs the fix could
be against linus/master or linux-next/master, which could be tried too.

> Btw, another nice aspect of this talking back to the bot is that before
> I, as a recipient of the bug report, go and try to prepare a guest or
> find a machine to reproduce properly, I can send a quick diff to the bot
> in the meantime and say, "try this on the guest. I have a hunch it might
> fix it."

Yes, that'd be most convenient. In general the email interface could
be something like this:

       # "key: value" fields; if you Re: to an earlier bug report, they can be auto retrieved
       compiler: gcc-6 # optional
       base-commit: v4.10-rc8 # the robot knows kernel commits from hundreds of public git trees
       ---
       the patch
       ---
       attach kconfig files

> > Yeah we have a TODO to do email based on-demand service, which looks
> > close to your proposal.
>
> Cool. Ping me if you need testers.
>
> Thanks!

Thanks,
Fengguang