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=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, 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 81715C47083 for ; Wed, 2 Jun 2021 07:20:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5D13361375 for ; Wed, 2 Jun 2021 07:20:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231612AbhFBHVm (ORCPT ); Wed, 2 Jun 2021 03:21:42 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:40559 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230099AbhFBHVl (ORCPT ); Wed, 2 Jun 2021 03:21:41 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1622618398; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=X4nP3Ng969nG95ueTZmh5K5TsN/lZGqF7zfAlo06R84=; b=U7j2TpWJ42Qn/KFvKKkKOy7flRZKqCcy9WxDyvKeTqeqZAsoXK5k0IS5aWO7g6E01+ee+t zTC0lr8lua8F6e1QbvpzUSz07CbdqdBeTDhTeoNXps65yQNe8n6Ntpoxq2KP1OPa/JqW9Y bSISUY7eKr1lyMrz5NXy1o0QYXmZVCg= Received: from mail-pl1-f199.google.com (mail-pl1-f199.google.com [209.85.214.199]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-342-fCboMVxBNfShguC1QqU4zA-1; Wed, 02 Jun 2021 03:19:57 -0400 X-MC-Unique: fCboMVxBNfShguC1QqU4zA-1 Received: by mail-pl1-f199.google.com with SMTP id o9-20020a1709026b09b0290102b8314d05so652770plk.8 for ; Wed, 02 Jun 2021 00:19:57 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-transfer-encoding :content-language; bh=X4nP3Ng969nG95ueTZmh5K5TsN/lZGqF7zfAlo06R84=; b=JbDK4d4DjVWMgGp90REJeULObtmjwFJDJG3cgo7p69P5H4eBRwOG/rDcpkjlTZ4mUk tWuiW1pozAKBi17zDKAMi9fO0+GYfmexjnf+oo2SNtqYuRoxT7+NEddh4G8DFyP9W3HD V8GbOy/q3EJTDG6ftu+aaizQHswKdZoZj7x0OTWH1Bb2DHDtnp1GlL5jn6ewX3hNyFZA m6YBxbMr794jm9LS+rZQ7w7aSByMawDMvsPR9e4noHpxKplAq24qjlbIEmcwUpWg+rhS W8NLPh7Qs5lwSxRk/hE29e7LRwf1poOBM2/yyLymVlBsp7tfzVTfrIno9cbOtbvKta6T JmVw== X-Gm-Message-State: AOAM5326x/IyJPHqQIJNLGcbLcZ8RSMj4sm8GTyMgKHe757kcX63/G2B 1ClHeL29L3pWCAkAZ+Rb1pPnftHQnFt8QGml2CjTaw7JmPdS+59gWuWtd/BMrSfINav32MPQPND AU3pS7AjRBdBbymNe X-Received: by 2002:a62:cd46:0:b029:2ea:299c:d7bd with SMTP id o67-20020a62cd460000b02902ea299cd7bdmr490447pfg.72.1622618396346; Wed, 02 Jun 2021 00:19:56 -0700 (PDT) X-Google-Smtp-Source: ABdhPJzZ645Is1tmz07mckMTyAA4Mz50hpb0lkW6SxhGDP6TZI8rBAamuObw3kS2TVn4LZecUfJFGQ== X-Received: by 2002:a62:cd46:0:b029:2ea:299c:d7bd with SMTP id o67-20020a62cd460000b02902ea299cd7bdmr490428pfg.72.1622618396110; Wed, 02 Jun 2021 00:19:56 -0700 (PDT) Received: from wangxiaodeMacBook-Air.local ([209.132.188.80]) by smtp.gmail.com with ESMTPSA id p11sm15880530pgn.65.2021.06.02.00.19.52 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 02 Jun 2021 00:19:55 -0700 (PDT) Subject: Re: [PATCH] virtio-net: fix the kzalloc/kfree mismatch problem To: Leon Romanovsky Cc: Xuan Zhuo , "Guodeqing (A)" , "davem@davemloft.net" , "kuba@kernel.org" , "virtualization@lists.linux-foundation.org" , "netdev@vger.kernel.org" , Max Gurtovoy , "mst@redhat.com" References: <1621821978.04102-1-xuanzhuo@linux.alibaba.com> <36d1b92c-7dc5-f84e-ef86-980b15c39965@redhat.com> From: Jason Wang Message-ID: Date: Wed, 2 Jun 2021 15:19:46 +0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:78.0) Gecko/20100101 Thunderbird/78.10.2 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org 在 2021/6/2 下午1:50, Leon Romanovsky 写道: > On Mon, May 24, 2021 at 10:37:14AM +0800, Jason Wang wrote: >> 在 2021/5/24 上午10:06, Xuan Zhuo 写道: >>> On Mon, 24 May 2021 01:48:53 +0000, Guodeqing (A) wrote: >>>>> -----Original Message----- >>>>> From: Max Gurtovoy [mailto:mgurtovoy@nvidia.com] >>>>> Sent: Sunday, May 23, 2021 15:25 >>>>> To: Guodeqing (A) ; mst@redhat.com >>>>> Cc: jasowang@redhat.com; davem@davemloft.net; kuba@kernel.org; >>>>> virtualization@lists.linux-foundation.org; netdev@vger.kernel.org >>>>> Subject: Re: [PATCH] virtio-net: fix the kzalloc/kfree mismatch problem >>>>> >>>>> >>>>> On 5/22/2021 11:02 AM, guodeqing wrote: >>>>>> If the virtio_net device does not suppurt the ctrl queue feature, the >>>>>> vi->ctrl was not allocated, so there is no need to free it. >>>>> you don't need this check. >>>>> >>>>> from kfree doc: >>>>> >>>>> "If @objp is NULL, no operation is performed." >>>>> >>>>> This is not a bug. I've set vi->ctrl to be NULL in case !vi->has_cvq. >>>>> >>>>> >>>> yes, this is not a bug, the patch is just a optimization, because the vi->ctrl maybe >>>> be freed which was not allocated, this may give people a misunderstanding. >>>> Thanks. >>> I think it may be enough to add a comment, and the code does not need to be >>> modified. >>> >>> Thanks. >> >> Or even just leave the current code as is. A lot of kernel codes was wrote >> under the assumption that kfree() should deal with NULL. > It is not assumption but standard practice that can be seen as side > effect of "7) Centralized exiting of functions" section of coding-style.rst. > > Thanks I don't see the connection to the centralized exiting. Something like: if (foo)     kfree(foo); won't break the centralization. Thanks > 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=-5.7 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no 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 77A41C4708F for ; Wed, 2 Jun 2021 07:20:06 +0000 (UTC) Received: from smtp2.osuosl.org (smtp2.osuosl.org [140.211.166.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 2E2F361363 for ; Wed, 2 Jun 2021 07:20:06 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2E2F361363 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=virtualization-bounces@lists.linux-foundation.org Received: from localhost (localhost [127.0.0.1]) by smtp2.osuosl.org (Postfix) with ESMTP id EFBD2400D2; Wed, 2 Jun 2021 07:20:05 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp2.osuosl.org ([127.0.0.1]) by localhost (smtp2.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id wMCU1XIHt7sg; Wed, 2 Jun 2021 07:20:05 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [IPv6:2605:bc80:3010:104::8cd3:938]) by smtp2.osuosl.org (Postfix) with ESMTP id 3744D400BA; Wed, 2 Jun 2021 07:20:04 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id 0CB31C000D; Wed, 2 Jun 2021 07:20:04 +0000 (UTC) Received: from smtp4.osuosl.org (smtp4.osuosl.org [140.211.166.137]) by lists.linuxfoundation.org (Postfix) with ESMTP id B1BFBC0001 for ; Wed, 2 Jun 2021 07:20:02 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp4.osuosl.org (Postfix) with ESMTP id 9EFFA402EB for ; Wed, 2 Jun 2021 07:20:02 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Authentication-Results: smtp4.osuosl.org (amavisd-new); dkim=pass (1024-bit key) header.d=redhat.com Received: from smtp4.osuosl.org ([127.0.0.1]) by localhost (smtp4.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id kVmWtEoleV7q for ; Wed, 2 Jun 2021 07:20:00 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.8.0 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [216.205.24.124]) by smtp4.osuosl.org (Postfix) with ESMTPS id 5EF7C4029E for ; Wed, 2 Jun 2021 07:20:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1622618399; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=X4nP3Ng969nG95ueTZmh5K5TsN/lZGqF7zfAlo06R84=; b=D+7yk34r7OMmqz6aCUfwlvJ5igjOKYjeEc+zND1T+TPWPFjiMYZx3Gw4J9oRVBh5Ipois6 I4y7gSpCt1SylJ3QE/AxJJRcUR43HhzF9PsaEmNe/EozGeGuDhvEqEFKV1OXLK6oF7oviT jGbkeYHznSiHgGh9Meh2pURT/9oz1cM= Received: from mail-pg1-f199.google.com (mail-pg1-f199.google.com [209.85.215.199]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-463-HO_eQeFJNIqN5gq389KWlA-1; Wed, 02 Jun 2021 03:19:57 -0400 X-MC-Unique: HO_eQeFJNIqN5gq389KWlA-1 Received: by mail-pg1-f199.google.com with SMTP id s14-20020a63450e0000b029021f631b8861so1115935pga.20 for ; Wed, 02 Jun 2021 00:19:57 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-transfer-encoding :content-language; bh=X4nP3Ng969nG95ueTZmh5K5TsN/lZGqF7zfAlo06R84=; b=TBIWSqTlfOcEsV6kXn5+2gGht6yzx2SPZmdCiluru3k2/CoZtaDAbeUgLYcoGt4E+j sNo+moZf711xRmG0/A+iB8X6kTTNevFZaDM2R5Y3CrbV/64V+oHbnDgMfU12oFHST/F8 xbqqYP8bA+zX1alSq4mjSHM18WIVcCH6d2nFvmE6r4xXAAMjoNko8kOkHwNiyEuDulSY 3aIUpcpzKbm/07J/JLd4jYxaKeSNkile8qbZCzqYocDeP9H+b8EKh3wAlxwDMVdeQzdn x7jxgHW09y17LWPbA9tkRVPwe1MuWRP8Etmt4KKbHTcpBQMOu4kSeXzwG1hajv6Ovn7W pwUw== X-Gm-Message-State: AOAM532hMjWCUhlY2p6fx7mL77/pc3RpdvWu542s1TSs360lGRcLp47Q Xa1K2qFRCVXP9c9DBaXACJd2AoBgcyBhydRQ0Q2+r+qS2pjLdApxNSgFj86IhTXRlMll/lHMVpx X2pGS+IEJ9aT0fhfM5d85XTXsKEr6QbbU+dV4qlA7Kw== X-Received: by 2002:a62:cd46:0:b029:2ea:299c:d7bd with SMTP id o67-20020a62cd460000b02902ea299cd7bdmr490444pfg.72.1622618396346; Wed, 02 Jun 2021 00:19:56 -0700 (PDT) X-Google-Smtp-Source: ABdhPJzZ645Is1tmz07mckMTyAA4Mz50hpb0lkW6SxhGDP6TZI8rBAamuObw3kS2TVn4LZecUfJFGQ== X-Received: by 2002:a62:cd46:0:b029:2ea:299c:d7bd with SMTP id o67-20020a62cd460000b02902ea299cd7bdmr490428pfg.72.1622618396110; Wed, 02 Jun 2021 00:19:56 -0700 (PDT) Received: from wangxiaodeMacBook-Air.local ([209.132.188.80]) by smtp.gmail.com with ESMTPSA id p11sm15880530pgn.65.2021.06.02.00.19.52 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 02 Jun 2021 00:19:55 -0700 (PDT) Subject: Re: [PATCH] virtio-net: fix the kzalloc/kfree mismatch problem To: Leon Romanovsky References: <1621821978.04102-1-xuanzhuo@linux.alibaba.com> <36d1b92c-7dc5-f84e-ef86-980b15c39965@redhat.com> From: Jason Wang Message-ID: Date: Wed, 2 Jun 2021 15:19:46 +0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:78.0) Gecko/20100101 Thunderbird/78.10.2 MIME-Version: 1.0 In-Reply-To: Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=jasowang@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Language: en-US Cc: Max Gurtovoy , "Guodeqing \(A\)" , "netdev@vger.kernel.org" , "mst@redhat.com" , "virtualization@lists.linux-foundation.org" , "kuba@kernel.org" , "davem@davemloft.net" X-BeenThere: virtualization@lists.linux-foundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Linux virtualization List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: base64 Content-Type: text/plain; charset="utf-8"; Format="flowed" Errors-To: virtualization-bounces@lists.linux-foundation.org Sender: "Virtualization" CuWcqCAyMDIxLzYvMiDkuIvljYgxOjUwLCBMZW9uIFJvbWFub3Zza3kg5YaZ6YGTOgo+IE9uIE1v biwgTWF5IDI0LCAyMDIxIGF0IDEwOjM3OjE0QU0gKzA4MDAsIEphc29uIFdhbmcgd3JvdGU6Cj4+ IOWcqCAyMDIxLzUvMjQg5LiK5Y2IMTA6MDYsIFh1YW4gWmh1byDlhpnpgZM6Cj4+PiBPbiBNb24s IDI0IE1heSAyMDIxIDAxOjQ4OjUzICswMDAwLCBHdW9kZXFpbmcgKEEpIDxnZWZmcmV5Lmd1b0Bo dWF3ZWkuY29tPiB3cm90ZToKPj4+Pj4gLS0tLS1PcmlnaW5hbCBNZXNzYWdlLS0tLS0KPj4+Pj4g RnJvbTogTWF4IEd1cnRvdm95IFttYWlsdG86bWd1cnRvdm95QG52aWRpYS5jb21dCj4+Pj4+IFNl bnQ6IFN1bmRheSwgTWF5IDIzLCAyMDIxIDE1OjI1Cj4+Pj4+IFRvOiBHdW9kZXFpbmcgKEEpIDxn ZWZmcmV5Lmd1b0BodWF3ZWkuY29tPjsgbXN0QHJlZGhhdC5jb20KPj4+Pj4gQ2M6IGphc293YW5n QHJlZGhhdC5jb207IGRhdmVtQGRhdmVtbG9mdC5uZXQ7IGt1YmFAa2VybmVsLm9yZzsKPj4+Pj4g dmlydHVhbGl6YXRpb25AbGlzdHMubGludXgtZm91bmRhdGlvbi5vcmc7IG5ldGRldkB2Z2VyLmtl cm5lbC5vcmcKPj4+Pj4gU3ViamVjdDogUmU6IFtQQVRDSF0gdmlydGlvLW5ldDogZml4IHRoZSBr emFsbG9jL2tmcmVlIG1pc21hdGNoIHByb2JsZW0KPj4+Pj4KPj4+Pj4KPj4+Pj4gT24gNS8yMi8y MDIxIDExOjAyIEFNLCBndW9kZXFpbmcgd3JvdGU6Cj4+Pj4+PiBJZiB0aGUgdmlydGlvX25ldCBk ZXZpY2UgZG9lcyBub3Qgc3VwcHVydCB0aGUgY3RybCBxdWV1ZSBmZWF0dXJlLCB0aGUKPj4+Pj4+ IHZpLT5jdHJsIHdhcyBub3QgYWxsb2NhdGVkLCBzbyB0aGVyZSBpcyBubyBuZWVkIHRvIGZyZWUg aXQuCj4+Pj4+IHlvdSBkb24ndCBuZWVkIHRoaXMgY2hlY2suCj4+Pj4+Cj4+Pj4+IGZyb20ga2Zy ZWUgZG9jOgo+Pj4+Pgo+Pj4+PiAiSWYgQG9ianAgaXMgTlVMTCwgbm8gb3BlcmF0aW9uIGlzIHBl cmZvcm1lZC4iCj4+Pj4+Cj4+Pj4+IFRoaXMgaXMgbm90IGEgYnVnLiBJJ3ZlIHNldCB2aS0+Y3Ry bCB0byBiZSBOVUxMIGluIGNhc2UgIXZpLT5oYXNfY3ZxLgo+Pj4+Pgo+Pj4+Pgo+Pj4+ICAgICB5 ZXMsICB0aGlzIGlzIG5vdCBhIGJ1ZywgdGhlIHBhdGNoIGlzIGp1c3QgYSBvcHRpbWl6YXRpb24s IGJlY2F1c2UgdGhlIHZpLT5jdHJsIG1heWJlCj4+Pj4gICAgIGJlIGZyZWVkIHdoaWNoICB3YXMg bm90IGFsbG9jYXRlZCwgdGhpcyBtYXkgZ2l2ZSBwZW9wbGUgYSBtaXN1bmRlcnN0YW5kaW5nLgo+ Pj4+ICAgICBUaGFua3MuCj4+PiBJIHRoaW5rIGl0IG1heSBiZSBlbm91Z2ggdG8gYWRkIGEgY29t bWVudCwgYW5kIHRoZSBjb2RlIGRvZXMgbm90IG5lZWQgdG8gYmUKPj4+IG1vZGlmaWVkLgo+Pj4K Pj4+IFRoYW5rcy4KPj4KPj4gT3IgZXZlbiBqdXN0IGxlYXZlIHRoZSBjdXJyZW50IGNvZGUgYXMg aXMuIEEgbG90IG9mIGtlcm5lbCBjb2RlcyB3YXMgd3JvdGUKPj4gdW5kZXIgdGhlIGFzc3VtcHRp b24gdGhhdCBrZnJlZSgpIHNob3VsZCBkZWFsIHdpdGggTlVMTC4KPiBJdCBpcyBub3QgYXNzdW1w dGlvbiBidXQgc3RhbmRhcmQgcHJhY3RpY2UgdGhhdCBjYW4gYmUgc2VlbiBhcyBzaWRlCj4gZWZm ZWN0IG9mICI3KSBDZW50cmFsaXplZCBleGl0aW5nIG9mIGZ1bmN0aW9ucyIgc2VjdGlvbiBvZiBj b2Rpbmctc3R5bGUucnN0Lgo+Cj4gVGhhbmtzCgoKSSBkb24ndCBzZWUgdGhlIGNvbm5lY3Rpb24g dG8gdGhlIGNlbnRyYWxpemVkIGV4aXRpbmcuCgpTb21ldGhpbmcgbGlrZToKCmlmIChmb28pCiDC oMKgwqAga2ZyZWUoZm9vKTsKCndvbid0IGJyZWFrIHRoZSBjZW50cmFsaXphdGlvbi4KClRoYW5r cwoKCj4KCl9fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fClZp cnR1YWxpemF0aW9uIG1haWxpbmcgbGlzdApWaXJ0dWFsaXphdGlvbkBsaXN0cy5saW51eC1mb3Vu ZGF0aW9uLm9yZwpodHRwczovL2xpc3RzLmxpbnV4Zm91bmRhdGlvbi5vcmcvbWFpbG1hbi9saXN0 aW5mby92aXJ0dWFsaXphdGlvbg==