On 2/12/24 22:38, Suren Baghdasaryan wrote: > Use __GFP_NO_OBJ_EXT to prevent recursions when allocating slabobj_ext > objects. Also prevent slabobj_ext allocations for kmem_cache objects. > > Signed-off-by: Suren Baghdasaryan <surenb@xxxxxxxxxx> > --- > mm/slab.h | 6 ++++++ > mm/slab_common.c | 2 ++ > 2 files changed, 8 insertions(+) > > diff --git a/mm/slab.h b/mm/slab.h > index 436a126486b5..f4ff635091e4 100644 > --- a/mm/slab.h > +++ b/mm/slab.h > @@ -589,6 +589,12 @@ prepare_slab_obj_exts_hook(struct kmem_cache *s, gfp_t flags, void *p) > if (!need_slab_obj_ext()) > return NULL; > > + if (s->flags & SLAB_NO_OBJ_EXT) > + return NULL; > + > + if (flags & __GFP_NO_OBJ_EXT) > + return NULL; Since we agreed to postpone this function, when it appears later it can have those in. > slab = virt_to_slab(p); > if (!slab_obj_exts(slab) && > WARN(alloc_slab_obj_exts(slab, s, flags, false), > diff --git a/mm/slab_common.c b/mm/slab_common.c > index 6bfa1810da5e..83fec2dd2e2d 100644 > --- a/mm/slab_common.c > +++ b/mm/slab_common.c > @@ -218,6 +218,8 @@ int alloc_slab_obj_exts(struct slab *slab, struct kmem_cache *s, > void *vec; > > gfp &= ~OBJCGS_CLEAR_MASK; > + /* Prevent recursive extension vector allocation */ > + gfp |= __GFP_NO_OBJ_EXT; And this could become part of 6/35 mm: introduce __GFP_NO_OBJ_EXT ... ? > vec = kcalloc_node(objects, sizeof(struct slabobj_ext), gfp, > slab_nid(slab)); > if (!vec)
