From f3ec502b6755a3bfb12c1c47025ef989ff9efc72 Mon Sep 17 00:00:00 2001 From: Suren Baghdasaryan Date: Wed, 25 Feb 2026 08:34:07 -0800 Subject: mm/slab: mark alloc tags empty for sheaves allocated with __GFP_NO_OBJ_EXT alloc_empty_sheaf() allocates sheaves from SLAB_KMALLOC caches using __GFP_NO_OBJ_EXT to avoid recursion, however it does not mark their allocation tags empty before freeing, which results in a warning when CONFIG_MEM_ALLOC_PROFILING_DEBUG is set. Fix this by marking allocation tags for such sheaves as empty. The problem was technically introduced in commit 4c0a17e28340 but only becomes possible to hit with commit 913ffd3a1bf5. Fixes: 4c0a17e28340 ("slab: prevent recursive kmalloc() in alloc_empty_sheaf()") Fixes: 913ffd3a1bf5 ("slab: handle kmalloc sheaves bootstrap") Reported-by: David Wang <00107082@163.com> Closes: https://lore.kernel.org/all/20260223155128.3849-1-00107082@163.com/ Analyzed-by: Harry Yoo Signed-off-by: Suren Baghdasaryan Reviewed-by: Harry Yoo Tested-by: Harry Yoo Tested-by: David Wang <00107082@163.com> Link: https://patch.msgid.link/20260225163407.2218712-1-surenb@google.com Signed-off-by: Vlastimil Babka (SUSE) --- include/linux/gfp_types.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include') diff --git a/include/linux/gfp_types.h b/include/linux/gfp_types.h index 814bb2892f99..6c75df30a281 100644 --- a/include/linux/gfp_types.h +++ b/include/linux/gfp_types.h @@ -139,6 +139,8 @@ enum { * %__GFP_ACCOUNT causes the allocation to be accounted to kmemcg. * * %__GFP_NO_OBJ_EXT causes slab allocation to have no object extension. + * mark_obj_codetag_empty() should be called upon freeing for objects allocated + * with this flag to indicate that their NULL tags are expected and normal. */ #define __GFP_RECLAIMABLE ((__force gfp_t)___GFP_RECLAIMABLE) #define __GFP_WRITE ((__force gfp_t)___GFP_WRITE) -- cgit v1.2.3