From nobody Thu Apr 2 13:36:19 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7A719C07E9D for ; Mon, 26 Sep 2022 15:37:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236411AbiIZPhl (ORCPT ); Mon, 26 Sep 2022 11:37:41 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59736 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235030AbiIZPfh (ORCPT ); Mon, 26 Sep 2022 11:35:37 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0624BBF76 for ; Mon, 26 Sep 2022 07:21:31 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 1CE9F60DE1 for ; Mon, 26 Sep 2022 14:21:31 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id DEDADC43470; Mon, 26 Sep 2022 14:21:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1664202090; bh=h7h74y8er6BoIqIK+NiPbrmtuB0Riz6+hSGGmV7Df14=; h=From:To:Cc:Subject:Date:From; b=lD8hNLrbF6sEGxqr/uldD4SMD1/tmZ91P2U76f5F94M3ttIK7XzG20QvpXfvGj6Jb byAuOwCw9q9DFaUA2ihHJmEs2/Apa+L8oF+kJ6dTBWqTFu+bGFp1k5qkrZ+sofiVDk spp+BQghx/FQTVuBbTO72vfrblLBPZNzUi0pU4cOEX9zCo/9IzhXBeA1Wp8ae3vOr5 RuzUuKqP8PekEgUcpthxxGBqASHtm5bgrdzR8/XerWfAL3+ikq7PKZIuTYSOJvLrhv GyyYv32PeOdsK+KDlCpsn3jgiU5LeuptI2idvQXUTMo3tHASXeHG89xzQOTYqEdEVx /zPc6DTKNUuXg== From: Chao Yu To: Christoph Lameter , Pekka Enberg , David Rientjes , Joonsoo Kim , Andrew Morton , Vlastimil Babka , Hugh Dickins Cc: chao@kernel.org, Chao Yu , Christophe JAILLET , Hyeonggon Yoo <42.hyeyoo@gmail.com>, Roman Gushchin , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [PATCH v3] mm/slub: clean up create_unique_id() Date: Mon, 26 Sep 2022 22:20:41 +0800 Message-Id: <20220926142042.2725-1-chao@kernel.org> X-Mailer: git-send-email 2.36.1 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Chao Yu As Christophe JAILLET suggested: In create_unique_id(), "looks that ID_STR_LENGTH could even be reduced to 32 or 16. The 2nd BUG_ON at the end of the function could certainly be just removed as well or remplaced by a: if (p > name + ID_STR_LENGTH - 1) { kfree(name); return -E; } " According to above suggestion, let's do below cleanups: 1. reduce ID_STR_LENGTH to 32, as the buffer size should be enough; 2. use WARN_ON instead of BUG_ON() and return error if check condition is true; 3. use snprintf instead of sprintf to avoid overflow. Link: https://lore.kernel.org/linux-mm/2025305d-16db-abdf-6cd3-1fb93371c2b4= @wanadoo.fr/ Fixes: 81819f0fc828 ("SLUB core") Suggested-by: Christophe JAILLET Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com> Signed-off-by: Chao Yu --- v3: - clean up codes - fix size parameter of snprintf() mm/slub.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/mm/slub.c b/mm/slub.c index 4b98dff9be8e..4d3ee0924533 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -5890,7 +5890,7 @@ static inline struct kset *cache_kset(struct kmem_cac= he *s) return slab_kset; } =20 -#define ID_STR_LENGTH 64 +#define ID_STR_LENGTH 32 =20 /* Create a unique string id for a slab cache: * @@ -5924,9 +5924,12 @@ static char *create_unique_id(struct kmem_cache *s) *p++ =3D 'A'; if (p !=3D name + 1) *p++ =3D '-'; - p +=3D sprintf(p, "%07u", s->size); + p +=3D snprintf(p, ID_STR_LENGTH - (p - name), "%07u", s->size); =20 - BUG_ON(p > name + ID_STR_LENGTH - 1); + if (WARN_ON(p > name + ID_STR_LENGTH - 1)) { + kfree(name); + return ERR_PTR(-EINVAL); + } return name; } =20 --=20 2.36.1