6.10-stable review patch. If anyone has any objections, please let me know.
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From: Rik van Riel riel@surriel.com
commit a371d558e6f3aed977a8a7346350557de5d25190 upstream.
In 782f8906f805 the freeing of kfence objects was moved from deep inside do_slab_free to the wrapper functions outside. This is a nice change, but unfortunately it missed one spot in __kmem_cache_free_bulk.
This results in a crash like this:
BUG skbuff_head_cache (Tainted: G S B E ): Padding overwritten. 0xffff88907fea0f00-0xffff88907fea0fff @offset=3840
slab_err (mm/slub.c:1129) free_to_partial_list (mm/slub.c:? mm/slub.c:4036) slab_pad_check (mm/slub.c:864 mm/slub.c:1290) check_slab (mm/slub.c:?) free_to_partial_list (mm/slub.c:3171 mm/slub.c:4036) kmem_cache_alloc_bulk (mm/slub.c:? mm/slub.c:4495 mm/slub.c:4586 mm/slub.c:4635) napi_build_skb (net/core/skbuff.c:348 net/core/skbuff.c:527 net/core/skbuff.c:549)
All the other callers to do_slab_free appear to be ok.
Add a kfence_free check in __kmem_cache_free_bulk to avoid the crash.
Reported-by: Chris Mason clm@meta.com Fixes: 782f8906f805 ("mm/slub: free KFENCE objects in slab_free_hook()") Cc: stable@kernel.org Signed-off-by: Rik van Riel riel@surriel.com Signed-off-by: Vlastimil Babka vbabka@suse.cz Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- mm/slub.c | 3 +++ 1 file changed, 3 insertions(+)
--- a/mm/slub.c +++ b/mm/slub.c @@ -4655,6 +4655,9 @@ static void __kmem_cache_free_bulk(struc if (!df.slab) continue;
+ if (kfence_free(df.freelist)) + continue; + do_slab_free(df.s, df.slab, df.freelist, df.tail, df.cnt, _RET_IP_); } while (likely(size));