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b=afXQTfY7mlWhg66Vp8DQgnBNBuw1R80YdSq++am4RaFjH5i2h1K/w9tWb1CCQMA9n B2+xwhktTQ3oczmJe/BO3NKZ9nOROjxpaaGuvQCMt2EUiUrYilQNF0N9GsBtIZYEFM 0NhWFxTTiNAc1f/z2ck6N1neKifOxCk39hprXyWSTrcUJA/iZjlraVBanBY2DjRT8O AyxeP+SnxAHgkRjI9YLUDopGnScNZiTxVg5ZjYHAyBFcXPDd7MfvbSYcDJphLcpDUs e935zO9VR4bVKaRzo+zWWHwk+RcvqJD9+pARw3BIcYc1l/Cuu39wEsD0ufUS9k48Yu keK25jwAMDxPQ== Message-ID: Date: Fri, 5 Jun 2026 14:59:22 +0900 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2] mm/slub: preserve original size in _kmalloc_nolock_noprof retry path To: hu.shengming@zte.com.cn, vbabka@kernel.org, akpm@linux-foundation.org Cc: hao.li@linux.dev, cl@gentwo.org, rientjes@google.com, roman.gushchin@linux.dev, linux-mm@kvack.org, linux-kernel@vger.kernel.org, zhang.run@zte.com.cn, cai.qu@zte.com.cn References: <202606042027323804pk3MRY42Jy7y42OHAhQZ@zte.com.cn> Content-Language: en-US From: Harry Yoo In-Reply-To: <202606042027323804pk3MRY42Jy7y42OHAhQZ@zte.com.cn> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="------------mvMhvM0STHKjAKiB8hmyrDMn" X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 4636620004 X-Stat-Signature: gjnos5qsdzehhnrrqpk5thssg3xt5835 X-Rspam-User: X-HE-Tag: 1780639175-542832 X-HE-Meta: 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 g+MZTOG1 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 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --------------mvMhvM0STHKjAKiB8hmyrDMn Content-Type: multipart/mixed; boundary="------------UaqwdqBkjfBUljnSAbpOsztD"; protected-headers="v1" From: Harry Yoo To: hu.shengming@zte.com.cn, vbabka@kernel.org, akpm@linux-foundation.org Cc: hao.li@linux.dev, cl@gentwo.org, rientjes@google.com, roman.gushchin@linux.dev, linux-mm@kvack.org, linux-kernel@vger.kernel.org, zhang.run@zte.com.cn, cai.qu@zte.com.cn Message-ID: Subject: Re: [PATCH v2] mm/slub: preserve original size in _kmalloc_nolock_noprof retry path References: <202606042027323804pk3MRY42Jy7y42OHAhQZ@zte.com.cn> In-Reply-To: <202606042027323804pk3MRY42Jy7y42OHAhQZ@zte.com.cn> --------------UaqwdqBkjfBUljnSAbpOsztD Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable On 6/4/26 9:27 PM, hu.shengming@zte.com.cn wrote: > From: Shengming Hu >=20 > _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. >=20 > 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 th= e > valid kmalloc range and hiding overflows. >=20 > Keep the caller requested size separately as orig_size and pass it to > the allocation/debug/KASAN paths. Continue using `size` as the retry ca= che > selector. >=20 > Fixes: af92793e52c3 ("slab: Introduce kmalloc_nolock() and kfree_nolock= ()") > Signed-off-by: Shengming Hu > --- > Changes in v2: > - Use an explicit orig_size variable instead of bucket_size, as suggest= ed > by Harry and Vlastimil. > - Link to v1: https://lore.kernel.org/all/20260603211011530GqLSXP_rgcuQ= dR47IGQLL@zte.com.cn/ >=20 > --- Reviewed-by: Harry Yoo (Oracle) --=20 Cheers, Harry / Hyeonggon --------------UaqwdqBkjfBUljnSAbpOsztD-- --------------mvMhvM0STHKjAKiB8hmyrDMn Content-Type: application/pgp-signature; name="OpenPGP_signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="OpenPGP_signature.asc" -----BEGIN PGP SIGNATURE----- iHUEARYKAB0WIQQQ1ub6gR5ogjaKRmOGXBN6rc5S1gUCaiJluwAKCRCGXBN6rc5S 1mDiAQDMsuhI+fb3bj0yV2uXPZmU7SL6rZGXaVTpa+0qqfyOXAEA4c7/8ULItr0w L8g4FZ2T8JQFVYrjv1BlKTwU2h5EdAY= =ADM0 -----END PGP SIGNATURE----- --------------mvMhvM0STHKjAKiB8hmyrDMn--