Re: KASAN: stack-out-of-bounds in iov_iter_revert

[Sudip Mukherjee]

On Tue, Aug 3, 2021 at 11:34 AM Pavel Begunkov <asml.silence@xxxxxxxxx> wrote:
>
> On 8/3/21 8:47 AM, Sudip Mukherjee wrote:
> > On Mon, Aug 2, 2021 at 12:55 PM Pavel Begunkov <asml.silence@xxxxxxxxx> wrote:
> >>
> >> On 8/1/21 9:28 PM, Sudip Mukherjee wrote:
> >>> Hi Pavel,
> >>>
> >>> On Sun, Aug 1, 2021 at 9:52 AM Pavel Begunkov <asml.silence@xxxxxxxxx> wrote:
> >>>>
> >>>> On 8/1/21 1:10 AM, Pavel Begunkov wrote:
> >>>>> On 7/31/21 7:21 PM, Sudip Mukherjee wrote:
> >>>>>> Hi Jens, Pavel,
> >>>>>>
> >>>>>> We had been running syzkaller on v5.10.y and a "KASAN:
> >>>>>> stack-out-of-bounds in iov_iter_revert" was being reported on it. I
> >>>>>> got some time to check that today and have managed to get a syzkaller
> >>>>>> reproducer. I dont have a C reproducer which I can share but I can use
> >>>>>> the syz-reproducer to reproduce this with v5.14-rc3 and also with
> >>>>>> next-20210730.
> >>>>>
> >>>>> Can you try out the diff below? Not a full-fledged fix, but need to
> >>>>> check a hunch.
> >>>>>
> >>>>> If that's important, I was using this branch:
> >>>>> git://git.kernel.dk/linux-block io_uring-5.14
> >>>>
> >>>> Or better this one, just in case it ooopses on warnings.
> >>>
> >>> I tested this one on top of "git://git.kernel.dk/linux-block
> >>> io_uring-5.14" and the issue was still seen, but after the BUG trace I
> >>> got lots of "truncated wr" message. The trace is:
> >>
> >> That's interesting, thanks
> >> Can you share the syz reproducer?
> >
> > Unfortunately I dont have a C reproducer, but this is the reproducer
> > for syzkaller:
>
> Thanks. Maybe I'm not perfectly familiar with syz, but were there
> any options? Like threaded, collide, etc.?

Sorry, my  mistake. I am still learning how syzkaller works. And I
should have given the link to the report with my mail.
https://elisa-builder-00.iol.unh.edu/syzkaller/report?id=959057ecd2886ff0c38cc53fa9c8eae46c1d7496

And also, I now have a C reproducer also, if that helps.


-- 
Regards
Sudip