From mboxrd@z Thu Jan 1 00:00:00 1970 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 B75F7C07E9D for ; Mon, 26 Sep 2022 14:29:22 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 1376D8E005E; Mon, 26 Sep 2022 10:29:22 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 0E7778E0047; Mon, 26 Sep 2022 10:29:22 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id ECA828E005E; Mon, 26 Sep 2022 10:29:21 -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 DDEAD8E0047 for ; Mon, 26 Sep 2022 10:29:21 -0400 (EDT) Received: from smtpin30.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay02.hostedemail.com (Postfix) with ESMTP id AF49B120A26 for ; Mon, 26 Sep 2022 14:29:21 +0000 (UTC) X-FDA: 79954469322.30.A538F8A Received: from smtp-out2.suse.de (smtp-out2.suse.de [195.135.220.29]) by imf05.hostedemail.com (Postfix) with ESMTP id 415C0100008 for ; Mon, 26 Sep 2022 14:29:21 +0000 (UTC) Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out2.suse.de (Postfix) with ESMTPS id 102C91F899; Mon, 26 Sep 2022 14:29:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1664202560; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=msezDbUBbMMaEKZkaR9Cxg7iF8T83ElsnAJUDKpPaBM=; b=qPZo+vy6b2umJ1r6o0eIlrQ06OEMQ4zvC69M6QEaiJlY4+3Eivwa/ulX8MDfu2zOGJHtJo tvSai6xoNG7sTbRk80a0IjE7muA1CXjGJ++dupw47NnKxL3etjh/WTnH2FiL27s3XGsNeU dujJqNa9l6mIT7QjQ5nb+COTfmpiUPo= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1664202560; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=msezDbUBbMMaEKZkaR9Cxg7iF8T83ElsnAJUDKpPaBM=; b=Kty9zgf4Dhf1HiIqbS9E1dvVYDiIMeihfVRcBGfS2Q5OhvXsKNGUAQ6CXw7FRWeB4FA9wI 6ROk0Xl6Nnwt8YBQ== Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id BED5113486; Mon, 26 Sep 2022 14:29:19 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id WKyXLT+3MWPNCgAAMHmgww (envelope-from ); Mon, 26 Sep 2022 14:29:19 +0000 Message-ID: <61bbbf65-9397-ac7d-9b57-2bfe5f0375ff@suse.cz> Date: Mon, 26 Sep 2022 16:29:19 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.3.0 Subject: Re: [PATCH v3] mm/slub: clean up create_unique_id() Content-Language: en-US To: Chao Yu , Christoph Lameter , Pekka Enberg , David Rientjes , Joonsoo Kim , Andrew Morton , Hugh Dickins Cc: Chao Yu , Christophe JAILLET , Hyeonggon Yoo <42.hyeyoo@gmail.com>, Roman Gushchin , linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20220926142042.2725-1-chao@kernel.org> From: Vlastimil Babka In-Reply-To: <20220926142042.2725-1-chao@kernel.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1664202561; 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-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=msezDbUBbMMaEKZkaR9Cxg7iF8T83ElsnAJUDKpPaBM=; b=BjXn/H2++ugjEn06zh7gHpLvocrsG1y5ZbecKFCxYzJPBXWHzzG8tnRFgFiYBCi9YPqV1T RKau1urCx86gGuo5dJBTBRHc7uJ6loaIOfD29FuTpbXLs+j1Cb8OxaCOObpxbLgKtCE2eU 7S80IEOgERJ/hcdTNqXIWzEV3zaTKK8= ARC-Authentication-Results: i=1; imf05.hostedemail.com; dkim=pass header.d=suse.cz header.s=susede2_rsa header.b=qPZo+vy6; dkim=pass header.d=suse.cz header.s=susede2_ed25519 header.b=Kty9zgf4; dmarc=none; spf=pass (imf05.hostedemail.com: domain of vbabka@suse.cz designates 195.135.220.29 as permitted sender) smtp.mailfrom=vbabka@suse.cz ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1664202561; a=rsa-sha256; cv=none; b=wk6fGJAiB80w/B+UOdevyyqhy750cr7HdP6ngMjA05OujZ1gb8IRIeZx5vMlta2Yx+gO2s HfRarqiK7gd10PvqK7NbNZGD3iwWr5rUUzNuofg3wnbE1S0YAC1k3vByL6ZxJprBjyKOVk cjUDokIC6B/85TfydzSu0CwEJOM0GkQ= X-Rspam-User: X-Rspamd-Queue-Id: 415C0100008 X-Rspamd-Server: rspam01 X-Stat-Signature: q91rbj7twnqh9jaz7t7h5j3qmgm4jbhq Authentication-Results: imf05.hostedemail.com; dkim=pass header.d=suse.cz header.s=susede2_rsa header.b=qPZo+vy6; dkim=pass header.d=suse.cz header.s=susede2_ed25519 header.b=Kty9zgf4; dmarc=none; spf=pass (imf05.hostedemail.com: domain of vbabka@suse.cz designates 195.135.220.29 as permitted sender) smtp.mailfrom=vbabka@suse.cz X-HE-Tag: 1664202561-150679 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: On 9/26/22 16:20, Chao Yu wrote: > 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 Thanks, added to slab.git for-next. > --- > 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_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 +5924,12 @@ 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 - (p - name), "%07u", s->size); > > - 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; > } >