From patchwork Sun Sep 25 07:12:07 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chao Yu X-Patchwork-Id: 12988011 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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 08F73C54EE9 for ; Sun, 25 Sep 2022 15:23:18 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 1C9E98E001B; Sun, 25 Sep 2022 11:23:18 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 17BB68E0007; Sun, 25 Sep 2022 11:23:18 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 040E68E001B; Sun, 25 Sep 2022 11:23:17 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id E93398E0007 for ; Sun, 25 Sep 2022 11:23:17 -0400 (EDT) Received: from smtpin04.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay06.hostedemail.com (Postfix) with ESMTP id AAA5CAAB3B for ; Sun, 25 Sep 2022 15:23:17 +0000 (UTC) X-FDA: 79950976434.04.B8B74DA Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by imf17.hostedemail.com (Postfix) with ESMTP id 5CC5A40004 for ; Sun, 25 Sep 2022 15:23:17 +0000 (UTC) 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 67BB861375; Sun, 25 Sep 2022 15:23:16 +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 ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1664119397; a=rsa-sha256; cv=none; b=HGeiSBjup/5cB3Q84Tk9sL22EtaF5kaYothxe2nxZzQamuBcr26f0OIyfex3tecepAFZSp dhquih7Y/pWg7tzYpWyNARDIV3G64F4MczgGwBSRcFjZi5bWo95/cB3f1Ssx7kKkc2udQP N1ewTEH66g6krmS5x6b82GNA8o49mOk= ARC-Authentication-Results: i=1; imf17.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=pGG7sCCh; spf=pass (imf17.hostedemail.com: domain of chao@kernel.org designates 139.178.84.217 as permitted sender) smtp.mailfrom=chao@kernel.org; dmarc=pass (policy=none) header.from=kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1664119397; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-transfer-encoding:content-transfer-encoding: in-reply-to:references:dkim-signature; bh=I2YrKj0KZ6PK0i8HF3ExRdsWzEEndu4M3H7TwG0i8Ao=; b=bZBLWckZsLfGOfoFebz7oNjIIAY4UJcSQmYdyLKHB0y5XWh7nLoVgdo6+ZokP9UPKiB4R+ RN9PJwWKfAc1dXwIAWLM99MSypK1gLhwibbB4ZePK4lxYLkxmJ7ZOq2gmv0VjH9bbKtbx0 OqPEHqMtitBEXq9YBG4D6658nK/e61g= X-Stat-Signature: 3wx41cxaswdbpbytsc531cy3yw8bmant X-Rspam-User: Authentication-Results: imf17.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=pGG7sCCh; spf=pass (imf17.hostedemail.com: domain of chao@kernel.org designates 139.178.84.217 as permitted sender) smtp.mailfrom=chao@kernel.org; dmarc=pass (policy=none) header.from=kernel.org X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 5CC5A40004 X-HE-Tag: 1664119397-753177 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: 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_cache *s) return slab_kset; } -#define ID_STR_LENGTH 64 +#define ID_STR_LENGTH 32 /* Create a unique string id for a slab cache: * @@ -5924,9 +5924,13 @@ static char *create_unique_id(struct kmem_cache *s) *p++ = 'A'; if (p != name + 1) *p++ = '-'; - p += sprintf(p, "%07u", s->size); + p += snprintf(p, ID_STR_LENGTH - 1 - (p - name), "%07u", s->size); - 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; }