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 E49C4C433EF for ; Mon, 27 Sep 2021 02:08:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B5408610A2 for ; Mon, 27 Sep 2021 02:08:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232431AbhI0CJz (ORCPT ); Sun, 26 Sep 2021 22:09:55 -0400 Received: from szxga01-in.huawei.com ([45.249.212.187]:11981 "EHLO szxga01-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232289AbhI0CJx (ORCPT ); Sun, 26 Sep 2021 22:09:53 -0400 Received: from dggemv704-chm.china.huawei.com (unknown [172.30.72.53]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4HHmGp39q0zWMn5; Mon, 27 Sep 2021 10:06:58 +0800 (CST) Received: from dggpemm500001.china.huawei.com (7.185.36.107) by dggemv704-chm.china.huawei.com (10.3.19.47) 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 10:08:14 +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-Transfer-Encoding: 8bit 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 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org sorry，wrong 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, and > 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 = compound_order(page); > > - 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);