From nobody Sun Oct 5 16:14:19 2025 Received: from mail.nfschina.com (unknown [42.101.60.213]) by smtp.subspace.kernel.org (Postfix) with SMTP id 975D42E36EA; Fri, 1 Aug 2025 06:10:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=42.101.60.213 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754028664; cv=none; b=KiIKpszFVSEus5wzPYDzJQc1w9mnNBYIqtZmUpv9LF1xryCub4qPLwYygb1uUcnZa3ZkpZcRl5y9HK6ko2jDE/dHv4XZKUerNkBSrdRg/8XhNvUSR8/9s3GdnbOG3R7xmwBkNATobC4631CH+6BLyhiYtJO/rvdLXHiIwDvTeLU= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754028664; c=relaxed/simple; bh=Ym9LS3yppxibgeF7HIrF3lh1orpt7YhnVslPDlwYK2g=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=gbaZSHnY6/dsG/sKzoeye1cL0BiYnEIe7w4YtvWbWXqP7egA5V3SdKw1kU00zJ49fu1fxU/CASdmAS6Aueyx6yafLHZhCxhKMyjFaJLtiUBgN/yeMK4X2M9vRzATcYDWZI3oMKPUjcvObU6oljusLYHIN94yLYp+zWY0/XWFIxY= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=nfschina.com; spf=pass smtp.mailfrom=nfschina.com; arc=none smtp.client-ip=42.101.60.213 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=nfschina.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=nfschina.com Received: from liqiong-suma.shanghai.nfschina.local (unknown [180.167.10.98]) by mail.nfschina.com (MailData Gateway V2.8.8) with ESMTPSA id 1632060260753; Fri, 1 Aug 2025 14:10:47 +0800 (CST) X-MD-Sfrom: liqiong@nfschina.com X-MD-SrcIP: 180.167.10.98 From: Li Qiong To: Christoph Lameter , David Rientjes , Andrew Morton , Vlastimil Babka Cc: Roman Gushchin , Harry Yoo , linux-mm@kvack.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org, Li Qiong Subject: [PATCH v4] mm: slub: avoid deref of invalid free pointer in object_err() Date: Fri, 1 Aug 2025 14:10:36 +0800 Message-Id: <20250801061036.528069-1-liqiong@nfschina.com> X-Mailer: git-send-email 2.30.2 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" For debugging, object_err() prints free pointer of the object. However, if object is a invalid pointer, dereferncing `object + s->offset` can lead to a crash. Therefore, add check_valid_pointer() for the object. Fixes: 81819f0fc828 ("SLUB core") Cc: Signed-off-by: Li Qiong --- v2: - rephrase the commit message, add comment for object_err(). v3: - check object pointer in object_err(). v4: - restore changes in alloc_consistency_checks(). --- mm/slub.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/mm/slub.c b/mm/slub.c index 31e11ef256f9..17b91e74f7d9 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -1104,7 +1104,11 @@ static void object_err(struct kmem_cache *s, struct = slab *slab, return; =20 slab_bug(s, reason); - print_trailer(s, slab, object); + if (!check_valid_pointer(s, slab, object)) { + print_slab_info(slab); + pr_err("invalid object 0x%p\n", object); + } else + print_trailer(s, slab, object); add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE); =20 WARN_ON(1); --=20 2.30.2