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 03954C433EF for ; Mon, 27 Sep 2021 03:06:34 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 4E5D660F92 for ; Mon, 27 Sep 2021 03:06:33 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 4E5D660F92 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 DC8AB6B0071; Sun, 26 Sep 2021 23:06:32 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id D78266B0072; Sun, 26 Sep 2021 23:06:32 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id C668E900002; Sun, 26 Sep 2021 23:06:32 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0028.hostedemail.com [216.40.44.28]) by kanga.kvack.org (Postfix) with ESMTP id B76E26B0071 for ; Sun, 26 Sep 2021 23:06:32 -0400 (EDT) Received: from smtpin21.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 445C82CBC1 for ; Mon, 27 Sep 2021 03:06:32 +0000 (UTC) X-FDA: 78631865424.21.742FC21 Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) by imf18.hostedemail.com (Postfix) with ESMTP id 4A21D4002088 for ; Mon, 27 Sep 2021 03:06:31 +0000 (UTC) Received: from dggemv703-chm.china.huawei.com (unknown [172.30.72.57]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4HHnZ039bYzWNSn; Mon, 27 Sep 2021 11:05:12 +0800 (CST) Received: from dggpemm500001.china.huawei.com (7.185.36.107) by dggemv703-chm.china.huawei.com (10.3.19.46) 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 11:06:28 +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 11:06:28 +0800 Subject: Re: [PATCH resend] slub: Add back check for free nonslab objects To: Matthew Wilcox CC: , , Christoph Lameter , Pekka Enberg , David Rientjes , Joonsoo Kim , Andrew Morton , , References: <20210927021538.155991-1-wangkefeng.wang@huawei.com> From: Kefeng Wang Message-ID: <5fbb67aa-9651-6fb8-4339-a74ac53acb33@huawei.com> Date: Mon, 27 Sep 2021 11:06:27 +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: Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 7bit 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: rspam02 X-Rspamd-Queue-Id: 4A21D4002088 X-Stat-Signature: haksnim484pfg9myezhksgygw6q9hk7q Authentication-Results: imf18.hostedemail.com; dkim=none; dmarc=pass (policy=none) header.from=huawei.com; spf=pass (imf18.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: 1632711991-178194 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 2021/9/27 10:42, Matthew Wilcox wrote: > On Mon, Sep 27, 2021 at 10:15:38AM +0800, Kefeng Wang wrote: >> 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. > Is dump_page() really the best way to catch such a thing? I would have > thought that printing the address of 'object' would be more helpful. With no vmcore, dump_page() do help us to find a memory corruption issue. We could add 'object ' address print too. > >> @@ -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, "invalid free nonslab page"); > . >