Re: [PATCH] mm: Check writable zero page in page table check

[Huang, Shaoqin]

On 9/6/2022 2:50 AM, Edgecombe, Rick P wrote:
> On Sat, 2022-09-03 at 10:13 +0800, Huang, Shaoqin wrote:
> > > +     BUG_ON(is_zero_pfn(pfn) && rw);
> > > +
> >
> > Why we need use BUG_ON() here? Based on [1], we should avoid to use
> > the
> > BUG_ON() due to it will panic the machine.
> >
> > [1]:
> > https://lore.kernel.org/lkml/20220824163100.224449-1-david@xxxxxxxxxx/
>
> Yea, you are probably right. All the rest of this checker uses BUG_ON()
> though. Maybe they should all be something else? Just felt weird to
> have this be the only check that is different.
>
> I don't have any objections to changing it to WARN_ON(). Should I
> switch the rest of the checks here while I'm at it?

Yes. I think in most situation, WARN_ON() or WARN_ON_ONCE() is ok.