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 AAC32C54EE9 for ; Sun, 25 Sep 2022 15:23:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230509AbiIYPXX (ORCPT ); Sun, 25 Sep 2022 11:23:23 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49074 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229915AbiIYPXT (ORCPT ); Sun, 25 Sep 2022 11:23:19 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 642242DA96 for ; Sun, 25 Sep 2022 08:23:18 -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 ams.source.kernel.org (Postfix) with ESMTPS id 1C5A5B80A07 for ; Sun, 25 Sep 2022 15:23:17 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7F0A3C433C1; Sun, 25 Sep 2022 15:23:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1664119395; bh=mNE9p5/mRNRoN586/wzug966NONIBtlU0EfERJqekg8=; h=From:To:Cc:Subject:Date:From; b=pGG7sCChzjYrQ3TP6zxfy15lEwow248ybUpqJQRJnKuoKixP2lG/l8XhtDjX1T2KP A5LCCwlU5gft2m/+TWcFOexoy9dzW4LB1PJSUeFkeaGIoCc7aPM98+WuxXdRMF2wFX BPpjV+d0vi4oZUfp5KWuDM5Rj7soCIX1GEtjdbsGwQGtXpJKx27L81Nr3vD9mscxEd r/UkXDnr8nPsMP87zVmPLtYG+xXgMlkrwOR2ZbwFOJqRtJIb9lY0oji7UNNFMew/Ew knY5cIpiet6Pu1wueiJqi8S+jgxF1JIYRGVjmLy2Mm1Xz5/Yb3dimmdMwjgsLVb8JJ USChfrPalDuow== 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 v2] mm/slub: clean up create_unique_id() Date: Sun, 25 Sep 2022 15:12:07 +0800 Message-Id: <20220925071207.13183-1-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 --- v2: - add WARN_ON() instead of return error silently; - use snprintf instead of sprintf to avoid overflow. mm/slub.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/mm/slub.c b/mm/slub.c index 4b98dff9be8e..3d37a8a7b965 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 +5924,13 @@ 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 - 1 - (p - name), "%07u", s->size); =20 - BUG_ON(p > name + ID_STR_LENGTH - 1); + if (p > name + ID_STR_LENGTH - 1) { + WARN_ON(1); + kfree(name); + return ERR_PTR(-EINVAL); + } return name; } =20 --=20 2.36.1