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 X-Spam-Level: X-Spam-Status: No, score=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, UNPARSEABLE_RELAY,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 81EAFC33CB7 for ; Mon, 27 Jan 2020 17:00:16 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 45F77214AF for ; Mon, 27 Jan 2020 17:00:16 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 45F77214AF Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.alibaba.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id E9BB96B0006; Mon, 27 Jan 2020 12:00:15 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id E248A6B0007; Mon, 27 Jan 2020 12:00:15 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D3C9F6B0008; Mon, 27 Jan 2020 12:00:15 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0222.hostedemail.com [216.40.44.222]) by kanga.kvack.org (Postfix) with ESMTP id B9BCD6B0006 for ; Mon, 27 Jan 2020 12:00:15 -0500 (EST) Received: from smtpin08.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with SMTP id 569B4824805A for ; Mon, 27 Jan 2020 17:00:15 +0000 (UTC) X-FDA: 76424027190.08.shade06_3c31ab77e1146 X-HE-Tag: shade06_3c31ab77e1146 X-Filterd-Recvd-Size: 3281 Received: from out30-132.freemail.mail.aliyun.com (out30-132.freemail.mail.aliyun.com [115.124.30.132]) by imf46.hostedemail.com (Postfix) with ESMTP for ; Mon, 27 Jan 2020 17:00:13 +0000 (UTC) X-Alimail-AntiSpam:AC=PASS;BC=-1|-1;BR=01201311R791e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e04394;MF=yang.shi@linux.alibaba.com;NM=1;PH=DS;RN=4;SR=0;TI=SMTPD_---0Tocs7WW_1580144404; Received: from US-143344MP.local(mailfrom:yang.shi@linux.alibaba.com fp:SMTPD_---0Tocs7WW_1580144404) by smtp.aliyun-inc.com(127.0.0.1); Tue, 28 Jan 2020 01:00:06 +0800 Subject: Re: [PATCH] mm: mempolicy: use VM_BUG_ON_VMA in queue_pages_test_walk() To: Li Xinhai , akpm Cc: "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" References: <1579068565-110432-1-git-send-email-yang.shi@linux.alibaba.com> <2020011520081970082765@gmail.com> <2a9ad6d6-af98-987a-0878-6058702db912@linux.alibaba.com> <20200116235250155994144@gmail.com> From: Yang Shi Message-ID: <70b6680c-7d3c-e04e-9e12-aab69a906d19@linux.alibaba.com> Date: Mon, 27 Jan 2020 08:59:59 -0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.12; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 MIME-Version: 1.0 In-Reply-To: <20200116235250155994144@gmail.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US 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: On 1/16/20 7:52 AM, Li Xinhai wrote: > On 2020-01-16=C2=A0at 01:27=C2=A0Yang Shi=C2=A0wrote: >> >> On 1/15/20 4:08 AM, Li Xinhai wrote: >>> On 2020-01-15=C2=A0at 14:09=C2=A0Yang Shi=C2=A0wrote: >>>> The VM_BUG_ON() is already used by queue_pages_test_walk(), it sound= s >>>> better to dump more debug information by using VM_BUG_ON_VMA() to he= lp >>>> debugging. >>>> >>>> Signed-off-by: Yang Shi >>> The .test_walk() is to be called from pagewalk with the rule that 'st= art' >>> and 'end' must within range of vma, in case the rule is broke, we det= ect >>> it. This is not quite relevant to a bug of particular vma. >> But when you run into VMA range check failure, isn't it helpful to dum= p >> the VMA range information to ease debugging? And, VM_BUG_ON is already >> used in the code, I'm supposed the users may prefer more debug >> information dumped for debug kernel. >> > Got your point, it is already used better put more information. Hi Andrew, Would you like to take this patch for v5.6 or v5.7? It looks Xinhai=20 agrees with my point. Thanks, Yang >>>> --- >>>> mm/mempolicy.c | 2 +- >>>> 1 file changed, 1 insertion(+), 1 deletion(-) >>>> >>>> diff --git a/mm/mempolicy.c b/mm/mempolicy.c >>>> index 067cf7d..801d45d 100644 >>>> --- a/mm/mempolicy.c >>>> +++ b/mm/mempolicy.c >>>> @@ -621,7 +621,7 @@ static int queue_pages_test_walk(unsigned long s= tart, unsigned long end, >>>> unsigned long flags =3D qp->flags; >>>> >>>> /* range check first */ >>>> - VM_BUG_ON((vma->vm_start > start) || (vma->vm_end < end)); >>>> + VM_BUG_ON_VMA((vma->vm_start > start) || (vma->vm_end < end), vma)= ; >>>> >>>> if (!qp->first) { >>>> qp->first =3D vma; >>>> -- >>>> 1.8.3.1 >>>> >>>> > >