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 09538C433EF for ; Thu, 2 Dec 2021 02:54:16 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 504E96B0072; Wed, 1 Dec 2021 21:54:06 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 4B4B36B0073; Wed, 1 Dec 2021 21:54:06 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 3A29F6B0074; Wed, 1 Dec 2021 21:54:06 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0069.hostedemail.com [216.40.44.69]) by kanga.kvack.org (Postfix) with ESMTP id 2D7B06B0072 for ; Wed, 1 Dec 2021 21:54:06 -0500 (EST) Received: from smtpin11.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id E0C06180339B8 for ; Thu, 2 Dec 2021 02:53:55 +0000 (UTC) X-FDA: 78871334430.11.3CE6ED1 Received: from szxga08-in.huawei.com (szxga08-in.huawei.com [45.249.212.255]) by imf19.hostedemail.com (Postfix) with ESMTP id E4846B0000A2 for ; Thu, 2 Dec 2021 02:53:54 +0000 (UTC) Received: from dggpeml500021.china.huawei.com (unknown [172.30.72.53]) by szxga08-in.huawei.com (SkyGuard) with ESMTP id 4J4L7J5v4jz1DJlb; Thu, 2 Dec 2021 10:51:08 +0800 (CST) Received: from dggpeml500006.china.huawei.com (7.185.36.76) by dggpeml500021.china.huawei.com (7.185.36.21) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.20; Thu, 2 Dec 2021 10:53:51 +0800 Received: from [10.174.177.232] (10.174.177.232) by dggpeml500006.china.huawei.com (7.185.36.76) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.20; Thu, 2 Dec 2021 10:53:50 +0800 Subject: Re: [PATCH -next] mm: delete oversized WARN_ON() in kvmalloc() calls To: Bixuan Cui , , , CC: , , , References: <1638410784-48646-1-git-send-email-cuibixuan@linux.alibaba.com> From: Tang Yizhou Message-ID: <74508663-8c2d-5c83-147f-adad7b71d93b@huawei.com> Date: Thu, 2 Dec 2021 10:53:49 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.1.1 MIME-Version: 1.0 In-Reply-To: <1638410784-48646-1-git-send-email-cuibixuan@linux.alibaba.com> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.174.177.232] X-ClientProxiedBy: dggems706-chm.china.huawei.com (10.3.19.183) To dggpeml500006.china.huawei.com (7.185.36.76) X-CFilter-Loop: Reflected X-Rspamd-Queue-Id: E4846B0000A2 X-Stat-Signature: gp78etrxj4kzhq77gen5cmhi5wfuiu3p Authentication-Results: imf19.hostedemail.com; dkim=none; dmarc=pass (policy=quarantine) header.from=huawei.com; spf=pass (imf19.hostedemail.com: domain of tangyizhou@huawei.com designates 45.249.212.255 as permitted sender) smtp.mailfrom=tangyizhou@huawei.com X-Rspamd-Server: rspam02 X-HE-Tag: 1638413634-827586 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 2021/12/2 10:06, Bixuan Cui wrote: > Delete the WARN_ON() and return NULL directly for oversized parameter > in kvmalloc() calls. > Also add unlikely(). > The commit message should explain why we need to do this. Thanks. > Fixes: 7661809d493b ("mm: don't allow oversized kvmalloc() calls") > Signed-off-by: Bixuan Cui > --- > There are a lot of oversize warnings and patches about kvmalloc() calls > recently. Maybe these warnings are not very necessary. > > https://lore.kernel.org/all/YadOjJXMTjP85MQx@unreal > > The example of size check in __do_kmalloc_node(): > __do_kmalloc_node(size_t size, gfp_t flags, int node, unsigned long caller) > { > struct kmem_cache *cachep; > void *ret; > > if (unlikely(size > KMALLOC_MAX_CACHE_SIZE)) > return NULL; > cachep = kmalloc_slab(size, flags); > > mm/util.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/mm/util.c b/mm/util.c > index 7e433690..d26f19c 100644 > --- a/mm/util.c > +++ b/mm/util.c > @@ -587,7 +587,7 @@ void *kvmalloc_node(size_t size, gfp_t flags, int node) > return ret; > > /* Don't even allow crazy sizes */ > - if (WARN_ON_ONCE(size > INT_MAX)) > + if (unlikely(size > INT_MAX)) > return NULL; > > return __vmalloc_node(size, 1, flags, node, > Tang