Hi Tvrtko,
>
> On 17/02/2022 07:50, Vivek Kasireddy wrote:
> > While looking for next holes suitable for an allocation, although,
> > it is highly unlikely, make sure that the DECLARE_NEXT_HOLE_ADDR
> > macro is using a valid node before it extracts the rb_node from it.
>
> Was the need for this just a consequence of insufficient locking in the
> i915 patch?
[Kasireddy, Vivek] Partly, yes; but I figured since we are anyway doing
if (!entry || ..), it makes sense to dereference entry and extract the rb_node
after this check.
Thanks,
Vivek
>
> Regards,
>
> Tvrtko
>
> >
> > Cc: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxxxxxxxx>
> > Cc: Christian König <christian.koenig@xxxxxxx>
> > Signed-off-by: Vivek Kasireddy <vivek.kasireddy@xxxxxxxxx>
> > ---
> > drivers/gpu/drm/drm_mm.c | 5 +++--
> > 1 file changed, 3 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/drm_mm.c b/drivers/gpu/drm/drm_mm.c
> > index 8257f9d4f619..499d8874e4ed 100644
> > --- a/drivers/gpu/drm/drm_mm.c
> > +++ b/drivers/gpu/drm/drm_mm.c
> > @@ -389,11 +389,12 @@ first_hole(struct drm_mm *mm,
> > #define DECLARE_NEXT_HOLE_ADDR(name, first, last) \
> > static struct drm_mm_node *name(struct drm_mm_node *entry, u64 size) \
> > { \
> > - struct rb_node *parent, *node = &entry->rb_hole_addr; \
> > + struct rb_node *parent, *node; \
> > \
> > - if (!entry || RB_EMPTY_NODE(node)) \
> > + if (!entry || RB_EMPTY_NODE(&entry->rb_hole_addr)) \
> > return NULL; \
> > \
> > + node = &entry->rb_hole_addr; \
> > if (usable_hole_addr(node->first, size)) { \
> > node = node->first; \
> > while (usable_hole_addr(node->last, size)) \
