Re: [syzbot] [crypto?] KMSAN: uninit-value in __crc32c_le_base (3)

From: Alexander Potapenko
Date: Thu Dec 14 2023 - 09:55:54 EST


On Wed, Dec 13, 2023 at 10:58 PM 'Dave Chinner' via syzkaller-bugs
<syzkaller-bugs@xxxxxxxxxxxxxxxx> wrote:
>
> On Thu, Dec 14, 2023 at 08:16:07AM +1100, Dave Chinner wrote:
> > [cc linux-xfs@xxxxxxxxxxxxxxx because that's where all questions
> > about XFS stuff should be directed, not to random individual
> > developers. ]
> >
> > On Wed, Dec 13, 2023 at 11:49:50AM +0100, Alexander Potapenko wrote:
> > > Hi Christoph, Dave,
> > >
> > > The repro provided by Xingwei indeed works.
>
> Can you please test the patch below?

It fixed the problem for me, feel free to add:

Tested-by: Alexander Potapenko <glider@xxxxxxxxxx>

As for the time needed to detect the bug, note that kmemcheck was
never used together with syzkaller, so it couldn't have the chance to
find it.

KMSAN found this bug in April
(https://syzkaller.appspot.com/bug?extid=a6d6b8fffa294705dbd8), only
half a year after we started mounting XFS images on syzbot.
Right now it is among the top crashers, so fixing it might uncover
more interesting bugs in xfs.