Introduce __GFP_NO_OBJ_EXT flag in order to prevent recursive allocations
when allocating slabobj_ext on a slab.
Signed-off-by: Suren Baghdasaryan <surenb@xxxxxxxxxx>
Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx>
---
include/linux/gfp_types.h | 11 +++++++++++
mm/slub.c | 2 ++
2 files changed, 13 insertions(+)
diff --git a/include/linux/gfp_types.h b/include/linux/gfp_types.h
index 868c8fb1bbc1..e36e168d8cfd 100644
--- a/include/linux/gfp_types.h
+++ b/include/linux/gfp_types.h
@@ -52,6 +52,9 @@ enum {
#endif
#ifdef CONFIG_LOCKDEP
___GFP_NOLOCKDEP_BIT,
+#endif
+#ifdef CONFIG_SLAB_OBJ_EXT
+ ___GFP_NO_OBJ_EXT_BIT,
#endif
___GFP_LAST_BIT
};
@@ -93,6 +96,11 @@ enum {
#else
#define ___GFP_NOLOCKDEP 0
#endif
+#ifdef CONFIG_SLAB_OBJ_EXT
+#define ___GFP_NO_OBJ_EXT BIT(___GFP_NO_OBJ_EXT_BIT)
+#else
+#define ___GFP_NO_OBJ_EXT 0
+#endif
/*
* Physical address zone modifiers (see linux/mmzone.h - low four bits)
@@ -133,12 +141,15 @@ enum {
* node with no fallbacks or placement policy enforcements.
*
* %__GFP_ACCOUNT causes the allocation to be accounted to kmemcg.
+ *
+ * %__GFP_NO_OBJ_EXT causes slab allocation to have no object extension.
*/
#define __GFP_RECLAIMABLE ((__force gfp_t)___GFP_RECLAIMABLE)
#define __GFP_WRITE ((__force gfp_t)___GFP_WRITE)
#define __GFP_HARDWALL ((__force gfp_t)___GFP_HARDWALL)
#define __GFP_THISNODE ((__force gfp_t)___GFP_THISNODE)
#define __GFP_ACCOUNT ((__force gfp_t)___GFP_ACCOUNT)
+#define __GFP_NO_OBJ_EXT ((__force gfp_t)___GFP_NO_OBJ_EXT)
/**
* DOC: Watermark modifiers
diff --git a/mm/slub.c b/mm/slub.c
index 76fb600fbc80..ca803b2949fc 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -1899,6 +1899,8 @@ 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;
vec = kcalloc_node(objects, sizeof(struct slabobj_ext), gfp,
slab_nid(slab));
if (!vec)
--
2.44.0.rc0.258.g7320e95886-goog
