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[86.27.177.88]) by smtp.gmail.com with ESMTPSA id f8-20020adfb608000000b0020229d72a4esm12782580wre.38.2022.03.14.05.47.52 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 14 Mar 2022 05:47:52 -0700 (PDT) Date: Mon, 14 Mar 2022 12:47:50 +0000 From: Lee Jones To: "Michael S. Tsirkin" Subject: Re: [PATCH 1/1] vhost: Protect the virtqueue from being cleared whilst still in use Message-ID: References: <20220314084302.2933167-1-lee.jones@linaro.org> <20220314072137-mutt-send-email-mst@kernel.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20220314072137-mutt-send-email-mst@kernel.org> Cc: kvm@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org, virtualization@lists.linux-foundation.org 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" T24gTW9uLCAxNCBNYXIgMjAyMiwgTWljaGFlbCBTLiBUc2lya2luIHdyb3RlOgoKPiBPbiBNb24s IE1hciAxNCwgMjAyMiBhdCAwODo0MzowMkFNICswMDAwLCBMZWUgSm9uZXMgd3JvdGU6Cj4gPiB2 aG9zdF92c29ja19oYW5kbGVfdHhfa2ljaygpIGFscmVhZHkgaG9sZHMgdGhlIG11dGV4IGR1cmlu ZyBpdHMgY2FsbAo+ID4gdG8gdmhvc3RfZ2V0X3ZxX2Rlc2MoKS4gIEFsbCB3ZSBoYXZlIHRvIGRv IGhlcmUgaXMgdGFrZSB0aGUgc2FtZSBsb2NrCj4gPiBkdXJpbmcgdmlydHF1ZXVlIGNsZWFuLXVw IGFuZCB3ZSBtaXRpZ2F0ZSB0aGUgcmVwb3J0ZWQgaXNzdWVzLgo+ID4gCj4gPiBBbHNvIFdBUk4o KSBhcyBhIHByZWNhdXRpb25hcnkgbWVhc3VyZS4gIFRoZSBwdXJwb3NlIG9mIHRoaXMgaXMgdG8K PiA+IGNhcHR1cmUgcG9zc2libGUgZnV0dXJlIHJhY2UgY29uZGl0aW9ucyB3aGljaCBtYXkgcG9w IHVwIG92ZXIgdGltZS4KPiA+IAo+ID4gQ2M6IDxzdGFibGVAdmdlci5rZXJuZWwub3JnPgo+ID4g U2lnbmVkLW9mZi1ieTogTGVlIEpvbmVzIDxsZWUuam9uZXNAbGluYXJvLm9yZz4KPiAKPiBQbHMg cmVmZXIgdG8gbXkgcHJldmlvdXMgcmVzcG9uc2VzIHRvIHRoaXMgcGF0Y2guICBJJ2QgbGlrZSB0 byBzZWUgYW4KPiBhcmd1bWVudCBmb3Igd2h5IHRoaXMgd2lsbCBtYWtlIGZ1dHVyZSBidWdzIGxl c3MgYW5kIG5vdCBtb3JlIGxpa2VseS4KCklmIHlvdSB0aGluayB0aGUgcHJldmlvdXMgJ2NoZWNr IG93bmVyJyBwYXRjaCBmaXhlcyBhbGwgb2YgdGhlCmNvbmN1cnJlbmN5IGlzc3VlcywgdGhlbiB0 aGlzIHBhdGNoIGNhbiBiZSBkcm9wcGVkLgoKLS0gCkxlZSBKb25lcyBb5p2O55C85pavXQpQcmlu Y2lwYWwgVGVjaG5pY2FsIExlYWQgLSBEZXZlbG9wZXIgU2VydmljZXMKTGluYXJvLm9yZyDilIIg T3BlbiBzb3VyY2Ugc29mdHdhcmUgZm9yIEFybSBTb0NzCkZvbGxvdyBMaW5hcm86IEZhY2Vib29r IHwgVHdpdHRlciB8IEJsb2cKX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19f X19fX19fX18KVmlydHVhbGl6YXRpb24gbWFpbGluZyBsaXN0ClZpcnR1YWxpemF0aW9uQGxpc3Rz LmxpbnV4LWZvdW5kYXRpb24ub3JnCmh0dHBzOi8vbGlzdHMubGludXhmb3VuZGF0aW9uLm9yZy9t YWlsbWFuL2xpc3RpbmZvL3ZpcnR1YWxpemF0aW9u 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 90655C433F5 for ; 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[86.27.177.88]) by smtp.gmail.com with ESMTPSA id f8-20020adfb608000000b0020229d72a4esm12782580wre.38.2022.03.14.05.47.52 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 14 Mar 2022 05:47:52 -0700 (PDT) Date: Mon, 14 Mar 2022 12:47:50 +0000 From: Lee Jones To: "Michael S. Tsirkin" Cc: jasowang@redhat.com, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, stable@vger.kernel.org Subject: Re: [PATCH 1/1] vhost: Protect the virtqueue from being cleared whilst still in use Message-ID: References: <20220314084302.2933167-1-lee.jones@linaro.org> <20220314072137-mutt-send-email-mst@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20220314072137-mutt-send-email-mst@kernel.org> Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Mon, 14 Mar 2022, Michael S. Tsirkin wrote: > On Mon, Mar 14, 2022 at 08:43:02AM +0000, Lee Jones wrote: > > vhost_vsock_handle_tx_kick() already holds the mutex during its call > > to vhost_get_vq_desc(). All we have to do here is take the same lock > > during virtqueue clean-up and we mitigate the reported issues. > > > > Also WARN() as a precautionary measure. The purpose of this is to > > capture possible future race conditions which may pop up over time. > > > > Cc: > > Signed-off-by: Lee Jones > > Pls refer to my previous responses to this patch. I'd like to see an > argument for why this will make future bugs less and not more likely. If you think the previous 'check owner' patch fixes all of the concurrency issues, then this patch can be dropped. -- Lee Jones [李琼斯] Principal Technical Lead - Developer Services Linaro.org │ Open source software for Arm SoCs Follow Linaro: Facebook | Twitter | Blog