On Wed, Aug 13, 2025 at 02:02:07PM +0200, Pratyush Yadav wrote:
> On Wed, Aug 13 2025, Greg KH wrote:
>
> > On Tue, Aug 12, 2025 at 11:34:37PM -0700, Vipin Sharma wrote:
> >> On 2025-08-07 01:44:35, Pasha Tatashin wrote:
> >> > From: Pratyush Yadav <ptyadav@xxxxxxxxx>
> >> > +static void memfd_luo_unpreserve_folios(const struct memfd_luo_preserved_folio *pfolios,
> >> > + unsigned int nr_folios)
> >> > +{
> >> > + unsigned int i;
> >> > +
> >> > + for (i = 0; i < nr_folios; i++) {
> >> > + const struct memfd_luo_preserved_folio *pfolio = &pfolios[i];
> >> > + struct folio *folio;
> >> > +
> >> > + if (!pfolio->foliodesc)
> >> > + continue;
> >> > +
> >> > + folio = pfn_folio(PRESERVED_FOLIO_PFN(pfolio->foliodesc));
> >> > +
> >> > + kho_unpreserve_folio(folio);
> >>
> >> This one is missing WARN_ON_ONCE() similar to the one in
> >> memfd_luo_preserve_folios().
> >
> > So you really want to cause a machine to reboot and get a CVE issued for
> > this, if it could be triggered? That's bold :)
> >
> > Please don't. If that can happen, handle the issue and move on, don't
> > crash boxes.
>
> Why would a WARN() crash the machine? That is what BUG() does, not
> WARN().
See 'panic_on_warn' which is enabled in a few billion Linux systems
these days :(
