mm/slub: preserve original size in _kmalloc_nolock_noprof retry path

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_kmalloc_nolock_noprof() retries from the next kmalloc bucket when the
initial allocation fails. The retry currently reuses `size` as the
bucket selector and overwrites it with s->object_size + 1.

That value is later passed as the original allocation size to
__slab_alloc_node(), slab_post_alloc_hook() and kasan_kmalloc(). On a
successful retry this makes KASAN/slub-debug observe the retry bucket
selector rather than the caller requested size, potentially widening the
valid kmalloc range and hiding overflows.

Keep the caller requested size separately as orig_size and pass it to
the allocation/debug/KASAN paths. Continue using `size` as the retry cache
selector.

Fixes: af92793e52 ("slab: Introduce kmalloc_nolock() and kfree_nolock()")
Signed-off-by: Shengming Hu <hu.shengming@zte.com.cn>
Reviewed-by: Harry Yoo (Oracle) <harry@kernel.org>
Reviewed-by: Hao Li <hao.li@linux.dev>
Link: https://patch.msgid.link/202606042027323804pk3MRY42Jy7y42OHAhQZ@zte.com.cn
Signed-off-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>

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Shengming Hu 2026-06-04 20:27:32 +08:00 • committed by Vlastimil Babka (SUSE)

parent 0fc52deec1

commit 19b206b953

1 changed files with 4 additions and 3 deletions

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mm/slub.c

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