From nobody Sun Oct 5 12:52:21 2025 Received: from mail.nfschina.com (unknown [42.101.60.213]) by smtp.subspace.kernel.org (Postfix) with SMTP id CE8121D554; Mon, 4 Aug 2025 01:46:51 +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=1754272016; cv=none; b=i54rhc05KyUs0NGQJ7Rf5oBbx5KliaadGIOkDhKZER82Ya2qeQxa/Aa2pH/kWlSwKgLEwAS6IZvCWQExwNPioo84OZklJTRePiT8DmR3xKHPshy7eWYcwk71gKqqyMsLReXmJCAA4ppYYL3di1uYr+LkCbBoh7YslTM8P4SObrw= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754272016; c=relaxed/simple; bh=2QKwTsRobFd0MuAOwfvasN22K0nOFK16xy32eEWdvPc=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=pq+Jr5DisZlNDHfBP/7jn/PFa0AW6HKLkYVJqNyAHPcg43O5l6OoZkW5Hqi6TzvThwU4lGIyr5ReFUZ7K/fSaqnwZcdadegSj41FYFUepjWcxA1+TvAeKXAjxoQrSiSBj6GAhm7ZAoRilvYL7fgxKr6kWE1QslA6PvbCZs7847A= 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 B20F7601096DA; Mon, 4 Aug 2025 09:46:45 +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 v5] mm/slub: avoid accessing metadata when pointer is invalid in object_err() Date: Mon, 4 Aug 2025 09:46:25 +0800 Message-Id: <20250804014626.134396-1-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" object_err() reports details of an object for further debugging, such as the freelist pointer, redzone, etc. However, if the pointer is invalid, attempting to access object metadata can lead to a crash since it does not point to a valid object. In case check_valid_pointer() returns false for the pointer, only print the pointer value and skip accessing metadata. Fixes: 81819f0fc828 ("SLUB core") Cc: Signed-off-by: Li Qiong Reviewed-by: Harry Yoo --- v2: - rephrase the commit message, add comment for object_err(). v3: - check object pointer in object_err(). v4: - restore changes in alloc_consistency_checks(). v5: - rephrase message, fix code style. --- mm/slub.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/mm/slub.c b/mm/slub.c index 31e11ef256f9..b3eff1476c85 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -1104,7 +1104,12 @@ 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 pointer 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