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dkim=pass (2048-bit key) header.d=kernel.org Received: from smtp1.osuosl.org ([127.0.0.1]) by localhost (smtp1.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 3a4cs3inBMRH for ; Wed, 2 Jun 2021 12:59:29 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.8.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp1.osuosl.org (Postfix) with ESMTPS id D2A1E825BF for ; Wed, 2 Jun 2021 12:59:29 +0000 (UTC) Received: by mail.kernel.org (Postfix) with ESMTPSA id 670E8613F0; Wed, 2 Jun 2021 12:59:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1622638769; bh=3pTJF8Uw7RKI6z+SHgf84kmB3egP8O9uPLS0sfmmP6Y=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=jJwn1XKGECVm249aCOaXizl2zxEJYlGwPip5pQSbzBVOUKTcvSD3V7A9zz/XUjvHQ 9Djj/PboHWd1g7J0td/yAkFnHr7/xp/DNc9SC6HJElgU+Yq3Pnh06qK+ukHfRtdXSy XXF3oNcIYUWB4WOFV78kiyer8pUebR94BImLxLZJ4K2hWcx7VYfSzyHsPk2Zlynwgj 9GhKGKcrYSH4iZD6S8i27OoT1OpGN43ejs6RHOBC07KsJiIGhRTNAE5WugiEg/tKUL 2CLYyn7DKXbPUlhiFDYFYujTOJzs5gD5C73M1PxgBzeNRcjel5X1Kjby1l2/XbTwGt fwoN8lqTLZKHg== Date: Wed, 2 Jun 2021 15:59:25 +0300 From: Leon Romanovsky To: Jason Wang Subject: Re: [PATCH] virtio-net: fix the kzalloc/kfree mismatch problem Message-ID: References: <1621821978.04102-1-xuanzhuo@linux.alibaba.com> <36d1b92c-7dc5-f84e-ef86-980b15c39965@redhat.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: 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-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Errors-To: virtualization-bounces@lists.linux-foundation.org Sender: "Virtualization" T24gV2VkLCBKdW4gMDIsIDIwMjEgYXQgMDM6MTk6NDZQTSArMDgwMCwgSmFzb24gV2FuZyB3cm90 ZToKPiAKPiDlnKggMjAyMS82LzIg5LiL5Y2IMTo1MCwgTGVvbiBSb21hbm92c2t5IOWGmemBkzoK PiA+IE9uIE1vbiwgTWF5IDI0LCAyMDIxIGF0IDEwOjM3OjE0QU0gKzA4MDAsIEphc29uIFdhbmcg d3JvdGU6Cj4gPiA+IOWcqCAyMDIxLzUvMjQg5LiK5Y2IMTA6MDYsIFh1YW4gWmh1byDlhpnpgZM6 Cj4gPiA+ID4gT24gTW9uLCAyNCBNYXkgMjAyMSAwMTo0ODo1MyArMDAwMCwgR3VvZGVxaW5nIChB KSA8Z2VmZnJleS5ndW9AaHVhd2VpLmNvbT4gd3JvdGU6Cj4gPiA+ID4gPiA+IC0tLS0tT3JpZ2lu YWwgTWVzc2FnZS0tLS0tCj4gPiA+ID4gPiA+IEZyb206IE1heCBHdXJ0b3ZveSBbbWFpbHRvOm1n dXJ0b3ZveUBudmlkaWEuY29tXQo+ID4gPiA+ID4gPiBTZW50OiBTdW5kYXksIE1heSAyMywgMjAy MSAxNToyNQo+ID4gPiA+ID4gPiBUbzogR3VvZGVxaW5nIChBKSA8Z2VmZnJleS5ndW9AaHVhd2Vp LmNvbT47IG1zdEByZWRoYXQuY29tCj4gPiA+ID4gPiA+IENjOiBqYXNvd2FuZ0ByZWRoYXQuY29t OyBkYXZlbUBkYXZlbWxvZnQubmV0OyBrdWJhQGtlcm5lbC5vcmc7Cj4gPiA+ID4gPiA+IHZpcnR1 YWxpemF0aW9uQGxpc3RzLmxpbnV4LWZvdW5kYXRpb24ub3JnOyBuZXRkZXZAdmdlci5rZXJuZWwu b3JnCj4gPiA+ID4gPiA+IFN1YmplY3Q6IFJlOiBbUEFUQ0hdIHZpcnRpby1uZXQ6IGZpeCB0aGUg a3phbGxvYy9rZnJlZSBtaXNtYXRjaCBwcm9ibGVtCj4gPiA+ID4gPiA+IAo+ID4gPiA+ID4gPiAK PiA+ID4gPiA+ID4gT24gNS8yMi8yMDIxIDExOjAyIEFNLCBndW9kZXFpbmcgd3JvdGU6Cj4gPiA+ ID4gPiA+ID4gSWYgdGhlIHZpcnRpb19uZXQgZGV2aWNlIGRvZXMgbm90IHN1cHB1cnQgdGhlIGN0 cmwgcXVldWUgZmVhdHVyZSwgdGhlCj4gPiA+ID4gPiA+ID4gdmktPmN0cmwgd2FzIG5vdCBhbGxv Y2F0ZWQsIHNvIHRoZXJlIGlzIG5vIG5lZWQgdG8gZnJlZSBpdC4KPiA+ID4gPiA+ID4geW91IGRv bid0IG5lZWQgdGhpcyBjaGVjay4KPiA+ID4gPiA+ID4gCj4gPiA+ID4gPiA+IGZyb20ga2ZyZWUg ZG9jOgo+ID4gPiA+ID4gPiAKPiA+ID4gPiA+ID4gIklmIEBvYmpwIGlzIE5VTEwsIG5vIG9wZXJh dGlvbiBpcyBwZXJmb3JtZWQuIgo+ID4gPiA+ID4gPiAKPiA+ID4gPiA+ID4gVGhpcyBpcyBub3Qg YSBidWcuIEkndmUgc2V0IHZpLT5jdHJsIHRvIGJlIE5VTEwgaW4gY2FzZSAhdmktPmhhc19jdnEu Cj4gPiA+ID4gPiA+IAo+ID4gPiA+ID4gPiAKPiA+ID4gPiA+ICAgICB5ZXMsICB0aGlzIGlzIG5v dCBhIGJ1ZywgdGhlIHBhdGNoIGlzIGp1c3QgYSBvcHRpbWl6YXRpb24sIGJlY2F1c2UgdGhlIHZp LT5jdHJsIG1heWJlCj4gPiA+ID4gPiAgICAgYmUgZnJlZWQgd2hpY2ggIHdhcyBub3QgYWxsb2Nh dGVkLCB0aGlzIG1heSBnaXZlIHBlb3BsZSBhIG1pc3VuZGVyc3RhbmRpbmcuCj4gPiA+ID4gPiAg ICAgVGhhbmtzLgo+ID4gPiA+IEkgdGhpbmsgaXQgbWF5IGJlIGVub3VnaCB0byBhZGQgYSBjb21t ZW50LCBhbmQgdGhlIGNvZGUgZG9lcyBub3QgbmVlZCB0byBiZQo+ID4gPiA+IG1vZGlmaWVkLgo+ ID4gPiA+IAo+ID4gPiA+IFRoYW5rcy4KPiA+ID4gCj4gPiA+IE9yIGV2ZW4ganVzdCBsZWF2ZSB0 aGUgY3VycmVudCBjb2RlIGFzIGlzLiBBIGxvdCBvZiBrZXJuZWwgY29kZXMgd2FzIHdyb3RlCj4g PiA+IHVuZGVyIHRoZSBhc3N1bXB0aW9uIHRoYXQga2ZyZWUoKSBzaG91bGQgZGVhbCB3aXRoIE5V TEwuCj4gPiBJdCBpcyBub3QgYXNzdW1wdGlvbiBidXQgc3RhbmRhcmQgcHJhY3RpY2UgdGhhdCBj YW4gYmUgc2VlbiBhcyBzaWRlCj4gPiBlZmZlY3Qgb2YgIjcpIENlbnRyYWxpemVkIGV4aXRpbmcg b2YgZnVuY3Rpb25zIiBzZWN0aW9uIG9mIGNvZGluZy1zdHlsZS5yc3QuCj4gPiAKPiA+IFRoYW5r cwo+IAo+IAo+IEkgZG9uJ3Qgc2VlIHRoZSBjb25uZWN0aW9uIHRvIHRoZSBjZW50cmFsaXplZCBl eGl0aW5nLgo+IAo+IFNvbWV0aGluZyBsaWtlOgo+IAo+IGlmIChmb28pCj4gwqDCoMKgIGtmcmVl KGZvbyk7Cj4gCj4gd29uJ3QgYnJlYWsgdGhlIGNlbnRyYWxpemF0aW9uLgoKVGhlIGtleSB3b3Jk cyBhcmUgInNpZGUgZWZmZWN0Ii4gT25jZSB5b3UgY2VudHJhbGl6ZSBldmVyeXRoaW5nLCB5b3UK d29uJ3Qgd2FudCB0byBzZWUgImlmIChmb28pIGtmcmVlKGZvbykiIHNwYWdoZXR0aSBjb2RlLgoK T2YgY291cnNlIHN1Y2ggY29uc3RydWN0aW9uIGRvZXNuJ3QgYnJlYWsgYW55dGhpbmcsIGJ1dCB0 aGUgaWRlYSBpcwp0byByZWR1Y2UgdXNlbGVzcyBjb2RlIGFuZCBub3QgYWRkIGl0LgoKVGhhbmtz Cgo+IAo+IFRoYW5rcwo+IAo+IAo+ID4gCj4gCl9fX19fX19fX19fX19fX19fX19fX19fX19fX19f X19fX19fX19fX19fX19fX19fClZpcnR1YWxpemF0aW9uIG1haWxpbmcgbGlzdApWaXJ0dWFsaXph dGlvbkBsaXN0cy5saW51eC1mb3VuZGF0aW9uLm9yZwpodHRwczovL2xpc3RzLmxpbnV4Zm91bmRh dGlvbi5vcmcvbWFpbG1hbi9saXN0aW5mby92aXJ0dWFsaXphdGlvbg== 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=-6.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED 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 E717CC47083 for ; Wed, 2 Jun 2021 12:59:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CDB1F613FA for ; Wed, 2 Jun 2021 12:59:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229641AbhFBNBO (ORCPT ); Wed, 2 Jun 2021 09:01:14 -0400 Received: from mail.kernel.org ([198.145.29.99]:35966 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229579AbhFBNBM (ORCPT ); Wed, 2 Jun 2021 09:01:12 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 670E8613F0; Wed, 2 Jun 2021 12:59:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1622638769; bh=3pTJF8Uw7RKI6z+SHgf84kmB3egP8O9uPLS0sfmmP6Y=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=jJwn1XKGECVm249aCOaXizl2zxEJYlGwPip5pQSbzBVOUKTcvSD3V7A9zz/XUjvHQ 9Djj/PboHWd1g7J0td/yAkFnHr7/xp/DNc9SC6HJElgU+Yq3Pnh06qK+ukHfRtdXSy XXF3oNcIYUWB4WOFV78kiyer8pUebR94BImLxLZJ4K2hWcx7VYfSzyHsPk2Zlynwgj 9GhKGKcrYSH4iZD6S8i27OoT1OpGN43ejs6RHOBC07KsJiIGhRTNAE5WugiEg/tKUL 2CLYyn7DKXbPUlhiFDYFYujTOJzs5gD5C73M1PxgBzeNRcjel5X1Kjby1l2/XbTwGt fwoN8lqTLZKHg== Date: Wed, 2 Jun 2021 15:59:25 +0300 From: Leon Romanovsky To: Jason Wang 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" Subject: Re: [PATCH] virtio-net: fix the kzalloc/kfree mismatch problem Message-ID: References: <1621821978.04102-1-xuanzhuo@linux.alibaba.com> <36d1b92c-7dc5-f84e-ef86-980b15c39965@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Wed, Jun 02, 2021 at 03:19:46PM +0800, Jason Wang wrote: > > 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. The key words are "side effect". Once you centralize everything, you won't want to see "if (foo) kfree(foo)" spaghetti code. Of course such construction doesn't break anything, but the idea is to reduce useless code and not add it. Thanks > > Thanks > > > > >