From nobody Sun Oct 5 22:01:43 2025 Received: from mail.nfschina.com (unknown [42.101.60.213]) by smtp.subspace.kernel.org (Postfix) with SMTP id AD51729B0; Tue, 29 Jul 2025 08:15:25 +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=1753776932; cv=none; b=afBHrYMCxXROf/vJcq5PFnTS3bqyw2A00V/0PCuC80nWY/URySbtS6GwMair/YFlQPsn9UvAEW1AqLXibt1+ZzThpZIITM//qsJaS1V0QzakEDi1ykWdy0k8UvzQhiJXj3K3wsAPlHfc6UsqIA2GhK0dD/kAiBsZHbLOVKW1HAA= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753776932; c=relaxed/simple; bh=Bs/X5R/GBALhH9VjVnGog552EPM5nbD0DNhgnYK7alc=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=MK9qVN2ynLzbIFYvposf7R6b26Nm4E4F4UR+LpvD0VjRdAp7XZgfEI8wys6HcTF+4Cw345RxmH8CkgJIu9gLubmuKZE4VftDsd4mUqyfKSGXgLgcchDVag5hKrp/DwUABV6UmwiWTpoTYyWxVYARw+mCZNXgOSDpTA1Rxegg+zA= 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 72C7D6019D27D; Tue, 29 Jul 2025 16:15:12 +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 v3] mm: slub: avoid deref of free pointer in sanity checks if object is invalid Date: Tue, 29 Jul 2025 16:14:55 +0800 Message-Id: <20250729081455.3311961-1-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 check_valid_pointer() returns false for a object, dereferncing `object + s->offset` can lead to a crash. Therefore, print the object's address in such cases. Fixes: bb192ed9aa71 ("mm/slub: Convert most struct page to struct slab by s= patch") Cc: Signed-off-by: Li Qiong --- v2: - rephrase the commit message, add comment for object_err(). v3: - check object pointer in object_err(). --- mm/slub.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/mm/slub.c b/mm/slub.c index 31e11ef256f9..d3abae5a2193 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); @@ -1587,7 +1591,7 @@ static inline int alloc_consistency_checks(struct kme= m_cache *s, return 0; =20 if (!check_valid_pointer(s, slab, object)) { - object_err(s, slab, object, "Freelist Pointer check fails"); + slab_err(s, slab, "Freelist Pointer(0x%p) check fails", object); return 0; } =20 --=20 2.30.2