PROBLEM: Kernel oops when mounting a encryptData CIFS share with CONFIG_DEBUG_VIRTUAL

[Steve French]

If the patch is an improvement - I am ok with it.  Unless one of the
mm experts has better idea

On Fri, Jul 26, 2019 at 1:28 AM Cyrille Mucchietto
<cmucchietto at wallix.com> wrote:
>
> On 7/25/19 10:35 PM, Pavel Shilovsky wrote:
> ...
> >> mount works without CONFIG_DEBUG_VIRTUAL
> >>
> >> If we don't set CONFIG_VMAP_STACK mount works with CONFIG_DEBUG_VIRTUAL
> >> We have the following (very quick and dirty) patch :
> >> ...
> > Thanks for reporting this. The patch looks good to me. Did you test
> > your scenario all together with it (not only mounting)?
> >
> >
> > Best regards,
> > Pavel Shilovskiy
>
> We've done some tests (mount/unmount, copy/delete/move files) and it seems
> to be OK.
>
> We aren't sure that our patch corrects the root cause of this issue, as
> for our
> understanding, kernel stack with VMAP_STACK enabled might not be contiguous.
> If the stack is too big to be on one page and data are splitted accross non
> contiguous pages it might not work.
>
> Regards
>
> Cyrille Mucchietto
>
>


-- 
Thanks,

Steve