Re: [PATCH 6.12.y] mm, slab: clean up slab->obj_exts always

[Sasha Levin <sashal@kernel.org>]

[ Sasha's backport helper bot ]

Hi,

Summary of potential issues:
⚠️ Found matching upstream commit but patch is missing proper reference to it

Found matching upstream commit: be8250786ca94952a19ce87f98ad9906448bc9ef

WARNING: Author mismatch between patch and found commit:
Backport author: Suren Baghdasaryan<surenb@google.com>
Commit author: Zhenhua Huang<quic_zhenhuah@quicinc.com>

Status in newer kernel trees:
6.14.y | Present (different SHA1: 94107e5aed93)

Note: The patch differs from the upstream commit:
---
1:  be8250786ca94 ! 1:  86ffacf03afed mm, slab: clean up slab->obj_exts always
    @@ Commit message
         Acked-by: Suren Baghdasaryan <surenb@google.com>
         Link: https://patch.msgid.link/20250421075232.2165527-1-quic_zhenhuah@quicinc.com
         Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
    +    (cherry picked from commit be8250786ca94952a19ce87f98ad9906448bc9ef)
    +    [surenb: fixed trivial merge conflict in alloc_tagging_slab_alloc_hook(),
    +    skipped inlining free_slab_obj_exts() as it's already inline in 6.12]
    +    Signed-off-by: Suren Baghdasaryan <surenb@google.com>
     
      ## mm/slub.c ##
    -@@ mm/slub.c: int alloc_slab_obj_exts(struct slab *slab, struct kmem_cache *s,
    - 	return 0;
    - }
    - 
    --/* Should be called only if mem_alloc_profiling_enabled() */
    --static noinline void free_slab_obj_exts(struct slab *slab)
    -+static inline void free_slab_obj_exts(struct slab *slab)
    - {
    - 	struct slabobj_ext *obj_exts;
    - 
    -@@ mm/slub.c: static noinline void free_slab_obj_exts(struct slab *slab)
    +@@ mm/slub.c: static inline void free_slab_obj_exts(struct slab *slab)
      	slab->obj_exts = 0;
      }
      
    @@ mm/slub.c: static inline void free_slab_obj_exts(struct slab *slab)
      #endif /* CONFIG_SLAB_OBJ_EXT */
      
      #ifdef CONFIG_MEM_ALLOC_PROFILING
    -@@ mm/slub.c: __alloc_tagging_slab_alloc_hook(struct kmem_cache *s, void *object, gfp_t flags)
    +@@ mm/slub.c: prepare_slab_obj_exts_hook(struct kmem_cache *s, gfp_t flags, void *p)
      static inline void
      alloc_tagging_slab_alloc_hook(struct kmem_cache *s, void *object, gfp_t flags)
      {
    --	if (need_slab_obj_ext())
    -+	if (mem_alloc_profiling_enabled())
    - 		__alloc_tagging_slab_alloc_hook(s, object, flags);
    - }
    +-	if (need_slab_obj_ext()) {
    ++	if (mem_alloc_profiling_enabled()) {
    + 		struct slabobj_ext *obj_exts;
      
    + 		obj_exts = prepare_slab_obj_exts_hook(s, flags, object);
     @@ mm/slub.c: static __always_inline void account_slab(struct slab *slab, int order,
      static __always_inline void unaccount_slab(struct slab *slab, int order,
      					   struct kmem_cache *s)
---

Results of testing on various branches:

| Branch                    | Patch Apply | Build Test |
|---------------------------|-------------|------------|
| stable/linux-6.12.y       |  Success    |  Success   |