Re: fs: GPF in bd_mount

From: Dmitry Vyukov
Date: Mon Sep 05 2016 - 04:43:38 EST


On Sun, Sep 4, 2016 at 4:29 PM, Al Viro <viro@xxxxxxxxxxxxxxxxxx> wrote:
> On Sun, Sep 04, 2016 at 03:06:06PM +0100, Al Viro wrote:
>
>> Said that, I'm not sure why mount_pseudo() would be returning any errors;
>> rejection should happen in the caller (due to MS_NOUSER in the flags), but
>> I don't understand what would trigger it on mount_pseudo() level...
>
> I see what's going on, but I wonder if sget() is the right place for userns
> checks...


FWIW, the upstream patch fixes the crash for me.

Do I understand it correctly that there is no perfect branch for such
testing (testing that aims at catching regressions asap and not
reporting what's already fixed)? Both mainline and linux-next miss
some fixes and functionality that is present on the other branch,
right?