Re: [x86/mm/gup] 2947ba054a [ 71.329069] kernel BUG at include/linux/pagemap.h:151!

From: Kirill A. Shutemov
Date: Fri Mar 24 2017 - 07:50:29 EST


On Fri, Mar 24, 2017 at 11:51:53AM +0100, Peter Zijlstra wrote:
> On Fri, Mar 24, 2017 at 01:24:36PM +0300, Kirill A. Shutemov wrote:
>
> > I'm not sure what is the best way to fix this.
> > Few options:
> > - Drop the VM_BUG();
> > - Bump preempt count during __get_user_pages_fast();
> > - Use get_page() instead of page_cache_get_speculative() on x86.
> >
> > Any opinions?
>
> I think I'm in favour of the first; either remove or amend to include
> irqs_disabled() or so.
>
> This in favour of keeping the variants of GUP down.

Something like this?

-------------------8<-----------------------