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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 20024C433F5 for ; Mon, 27 Sep 2021 02:08:22 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 7DE8860FE7 for ; Mon, 27 Sep 2021 02:08:21 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 7DE8860FE7 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=huawei.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvack.org Received: by kanga.kvack.org (Postfix) id EF46C6B0071; Sun, 26 Sep 2021 22:08:20 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id EA1F86B0072; Sun, 26 Sep 2021 22:08:20 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D9169900002; 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Mon, 27 Sep 2021 10:08:14 +0800 Received: from [10.174.177.243] (10.174.177.243) by dggpemm500001.china.huawei.com (7.185.36.107) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.8; Mon, 27 Sep 2021 10:08:13 +0800 Subject: Re: [PATCH] slub: Add back check for free nonslab objects To: , , Christoph Lameter , Pekka Enberg , David Rientjes , Joonsoo Kim , Andrew Morton , , References: <20210927020922.87449-1-wangkefeng.wang@huawei.com> From: Kefeng Wang Message-ID: <05edb377-0168-6a16-d8a4-6dda77bb10e1@huawei.com> Date: Mon, 27 Sep 2021 10:08:13 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.7.0 MIME-Version: 1.0 In-Reply-To: <20210927020922.87449-1-wangkefeng.wang@huawei.com> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Language: en-US X-Originating-IP: [10.174.177.243] X-ClientProxiedBy: dggems704-chm.china.huawei.com (10.3.19.181) To dggpemm500001.china.huawei.com (7.185.36.107) X-CFilter-Loop: Reflected X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: E0867D000097 X-Stat-Signature: dgpapedwm51kahjfqnpx9dr6p946481f Authentication-Results: imf15.hostedemail.com; dkim=none; dmarc=pass (policy=none) header.from=huawei.com; spf=pass (imf15.hostedemail.com: domain of wangkefeng.wang@huawei.com designates 45.249.212.187 as permitted sender) smtp.mailfrom=wangkefeng.wang@huawei.com X-HE-Tag: 1632708499-973513 Content-Transfer-Encoding: quoted-printable 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: sorry=EF=BC=8Cwrong patch, please ignore On 2021/9/27 10:09, Kefeng Wang wrote: > After commit ("f227f0faf63b slub: fix unreclaimable slab stat for bulk > free"), the check for free nonslab page is replaced by VM_BUG_ON_PAGE, > which only check with CONFIG_DEBUG_VM enabled, but this config may > impact performance, so it only for debug. > > Commit ("0937502af7c9 slub: Add check for kfree() of non slab objects."= ) > add the ability, which should be needed in any configs to catch the > invalid free, they even could be potential issue, eg, memory corruption= , > use after free and double free, so replace VM_BUG_ON_PAGE to WARN_ON, a= nd > add dump_page() to help use to debug the issue. > > Signed-off-by: Kefeng Wang > --- > mm/slub.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/mm/slub.c b/mm/slub.c > index 3095b889fab4..1bfe09098485 100644 > --- a/mm/slub.c > +++ b/mm/slub.c > @@ -3522,7 +3522,8 @@ static inline void free_nonslab_page(struct page = *page, void *object) > { > unsigned int order =3D compound_order(page); > =20 > - VM_BUG_ON_PAGE(!PageCompound(page), page); > + if (WARN_ON(!PageCompound(page))) > + dump_page(page); > kfree_hook(object); > mod_lruvec_page_state(page, NR_SLAB_UNRECLAIMABLE_B, -(PAGE_SIZE << = order)); > __free_pages(page, order);