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 C9EB2C433F5 for ; Mon, 14 Mar 2022 12:48:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241519AbiCNMuC (ORCPT ); Mon, 14 Mar 2022 08:50:02 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34156 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237740AbiCNMtG (ORCPT ); Mon, 14 Mar 2022 08:49:06 -0400 Received: from mail-wr1-x434.google.com (mail-wr1-x434.google.com [IPv6:2a00:1450:4864:20::434]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5346A64FF for ; Mon, 14 Mar 2022 05:47:54 -0700 (PDT) Received: by mail-wr1-x434.google.com with SMTP id x15so23702838wru.13 for ; Mon, 14 Mar 2022 05:47:54 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:content-transfer-encoding:in-reply-to; bh=UcZz3PXNAXNeLX36v/bP5PcZAjppkzTqtYj3JQZLCdA=; b=ig3ZPDbuCYDJsY/LgK1lpVFFGCBJvNLc/orKd5+QKvhAz74QdogXuc35H6CwRfnHa+ hT4a6QXAcVyg2Z83vj3WOEp6qcGbrEEGflCZ39lr6oczDy0B3LoakQsSKEWHEhF25TGl 8hqA7CALrwlBQeqlQOh45Re1Edl+ybv98yo2khw1rSBH1+PRnC5+dhq1eAaKBczXqlJZ ul6xk3BFYCjhk7mvf7OU/zEMtmx7O3AMM19LQu/zS7QSrk84f2LvxIg8IXuLjexhJDQk I8Cyu7Kd22U9CgsLcEo1AWInzQOZJKa0GgYkv0oshHsaKztu5Zrw0S35lj3UhbLW2UTT zQNg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:content-transfer-encoding :in-reply-to; bh=UcZz3PXNAXNeLX36v/bP5PcZAjppkzTqtYj3JQZLCdA=; b=MBB2kA+TU3udfd9hxkbfBaAyQVZnE4dcMvrjo803NVGKMn3QYAiyowrrGaVFk/Nz0l SOWASPXQ4F6OAi0WV8YHj6vu+2y9ImVreDNY4iI+3begGIFaSNyp7eh/4dqvDi1kQLoh mptXSz2hNOPShrgrPCqnZ7U51+5phtKHqLrJZ4k+PsaO3fmYGrX1zt3s4Fr7xW8tYcqT XRYoGjnKf7rXY86CUBZFQ1GzOc7QxtZEOqBgXgVrYgwIzsyXtUhOC4undmCur1B5HpuR QGRPUPK9j1yCryLc/ld17Wgvxxn4jQUoiAyvWampOl5vrgrXNtq/Z1N9USmSu2bTOYkg MiWg== X-Gm-Message-State: AOAM5304HM5IEGUzMsnseHCQJYnpB9/pwNTKCRS10wVv9oAONoHYl0SR Dr2yK4l31zkpErsc7qmc4HX/FQ== X-Google-Smtp-Source: ABdhPJxbbfF5IE+ED+j6Qzjup3ymxmcmA/LwEtp0YD0fuDRr/NLeeKHy41JvH6RnmaYRzkrpBmXj8g== X-Received: by 2002:a5d:6d83:0:b0:203:6a0e:8854 with SMTP id l3-20020a5d6d83000000b002036a0e8854mr16161016wrs.259.1647262072830; Mon, 14 Mar 2022 05:47:52 -0700 (PDT) Received: from google.com (cpc155339-bagu17-2-0-cust87.1-3.cable.virginm.net. [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: linux-kernel@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