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 781F2C433EF for ; Wed, 2 Mar 2022 14:57:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243311AbiCBO6W (ORCPT ); Wed, 2 Mar 2022 09:58:22 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60104 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243298AbiCBO6S (ORCPT ); Wed, 2 Mar 2022 09:58:18 -0500 Received: from mail-wm1-x32e.google.com (mail-wm1-x32e.google.com [IPv6:2a00:1450:4864:20::32e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 628D513DD7 for ; Wed, 2 Mar 2022 06:57:33 -0800 (PST) Received: by mail-wm1-x32e.google.com with SMTP id bg16-20020a05600c3c9000b00380f6f473b0so3456427wmb.1 for ; Wed, 02 Mar 2022 06:57:33 -0800 (PST) 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=wGGyr8F/4yesRnDkleDkSeBi9/XbD7YGJTcIBLykmxo=; b=YAWW5HKlB7Eey/hbn/tEyKoY+Ej9P8bjmKwFJpG4WIH2K/pus2hP+RvzIjDv6V3z5p k6x5v3LHFzzK0yNYVc3/6rqsj7QQzSFP9PqTvboq8Gd2h2U5akBPL3gjR8Gis5rXW7a5 f5Wj0QWjydNWVbiao3cyHkss6w5fRltrK3+kbwT6yAe/CdOFs42vPOp9Mksavp1FhfDg b+8kmdCZBXU7N1sbqbnIx9h7JeO+bMDEWXRboAhQXSO6FrQS9Y2kIONVMIQBVPZeWrO0 GsIgMsxoTCsl6Mtqj6TTCwunX0DqqFgLwCazwzkBeT0HF1oYRmofMt0ZOyXz8dF5vh/a nxAQ== 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=wGGyr8F/4yesRnDkleDkSeBi9/XbD7YGJTcIBLykmxo=; b=kLC/Hp0XIRzKdXLioTbCC4YPEzxAXyLz3cKvnBlH2j5UH2gaAhkpGYyI+UEH0qMrz5 a/gB4dF+qtxh/SF0sMT+YlJvfsEWZ4dpbjhT8t0vmekcAl2kVw3/Qm+gm1hwptrZ1CKO QNpJmDK6yE7yR2wSXWD4A8GzAaZPfTrNT4pfHdGEcjZRqlAOYzf5GU4g+zUh9U4QD2w4 KkMDLqLkC3YEjydTRvckIgd8KrJMVRxEELjuAAbi/+EFz/x+Sd3wlqO7D+GpLUdrE+0L TZ6qqUfVThJ2nvv4E9Csdv36zJxxz/DKgemchumYLG/kQycnZZ/fF6VWW9fimwwuhuyV 6gsA== X-Gm-Message-State: AOAM531/IL2JUuSiVRVrnF7ifw3jm+VlnL825tDRo+n2GEkPX5BH9tog 6FH7H1rZQDYIDVjVJLqdjKC1MA== X-Google-Smtp-Source: ABdhPJxDjgY35zlNFNM4bX0OTXrJd0JfiswPqCzf7heVkctOxPWyBqq7cmIrMgVAjnLfYiYdzW+RlQ== X-Received: by 2002:a05:600c:40cf:b0:381:1f87:84c4 with SMTP id m15-20020a05600c40cf00b003811f8784c4mr102404wmh.181.1646233051757; Wed, 02 Mar 2022 06:57:31 -0800 (PST) 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 o204-20020a1ca5d5000000b0038331f2f951sm4751221wme.0.2022.03.02.06.57.27 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 02 Mar 2022 06:57:31 -0800 (PST) Date: Wed, 2 Mar 2022 14:57:26 +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, syzbot+adc3cb32385586bec859@syzkaller.appspotmail.com Subject: Re: [PATCH 1/1] vhost: Protect the virtqueue from being cleared whilst still in use Message-ID: References: <20220302075421.2131221-1-lee.jones@linaro.org> <20220302082021-mutt-send-email-mst@kernel.org> <20220302095045-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: <20220302095045-mutt-send-email-mst@kernel.org> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 02 Mar 2022, Michael S. Tsirkin wrote: > On Wed, Mar 02, 2022 at 01:56:35PM +0000, Lee Jones wrote: > > On Wed, 02 Mar 2022, Michael S. Tsirkin wrote: > > > > > On Wed, Mar 02, 2022 at 07:54:21AM +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 is take the same lock > > > > during virtqueue clean-up and we mitigate the reported issues. > > > > > > > > Link: https://syzkaller.appspot.com/bug?extid=279432d30d825e63ba00 > > > > > > > > Cc: > > > > Reported-by: syzbot+adc3cb32385586bec859@syzkaller.appspotmail.com > > > > Signed-off-by: Lee Jones > > > > --- > > > > drivers/vhost/vhost.c | 2 ++ > > > > 1 file changed, 2 insertions(+) > > > > > > > > diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c > > > > index 59edb5a1ffe28..bbaff6a5e21b8 100644 > > > > --- a/drivers/vhost/vhost.c > > > > +++ b/drivers/vhost/vhost.c > > > > @@ -693,6 +693,7 @@ void vhost_dev_cleanup(struct vhost_dev *dev) > > > > int i; > > > > > > > > for (i = 0; i < dev->nvqs; ++i) { > > > > + mutex_lock(&dev->vqs[i]->mutex); > > > > if (dev->vqs[i]->error_ctx) > > > > eventfd_ctx_put(dev->vqs[i]->error_ctx); > > > > if (dev->vqs[i]->kick) > > > > @@ -700,6 +701,7 @@ void vhost_dev_cleanup(struct vhost_dev *dev) > > > > if (dev->vqs[i]->call_ctx.ctx) > > > > eventfd_ctx_put(dev->vqs[i]->call_ctx.ctx); > > > > vhost_vq_reset(dev, dev->vqs[i]); > > > > + mutex_unlock(&dev->vqs[i]->mutex); > > > > } > > > > > > So this is a mitigation plan but the bug is still there though > > > we don't know exactly what it is. I would prefer adding something like > > > WARN_ON(mutex_is_locked(vqs[i]->mutex) here - does this make sense? > > > > As a rework to this, or as a subsequent patch? > > Can be a separate patch. > > > Just before the first lock I assume? > > I guess so, yes. No problem. Patch to follow. I'm also going to attempt to debug the root cause, but I'm new to this subsystem to it might take a while for me to get my head around. -- Lee Jones [李琼斯] Principal Technical Lead - Developer Services Linaro.org │ Open source software for Arm SoCs Follow Linaro: Facebook | Twitter | Blog 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 smtp3.osuosl.org (smtp3.osuosl.org [140.211.166.136]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 48C91C433EF for ; Wed, 2 Mar 2022 14:57:38 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp3.osuosl.org (Postfix) with ESMTP id E27A360F00; Wed, 2 Mar 2022 14:57:37 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp3.osuosl.org ([127.0.0.1]) by localhost (smtp3.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id lcvUKY5ICWtj; Wed, 2 Mar 2022 14:57:37 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [140.211.9.56]) by smtp3.osuosl.org (Postfix) with ESMTPS id 5A5E060EFD; Wed, 2 Mar 2022 14:57:36 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id 13082C0012; Wed, 2 Mar 2022 14:57:36 +0000 (UTC) Received: from smtp4.osuosl.org (smtp4.osuosl.org [IPv6:2605:bc80:3010::137]) by lists.linuxfoundation.org (Postfix) with ESMTP id D5419C000B for ; Wed, 2 Mar 2022 14:57:34 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp4.osuosl.org (Postfix) with ESMTP id B53C74035D for ; Wed, 2 Mar 2022 14:57:34 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Authentication-Results: smtp4.osuosl.org (amavisd-new); dkim=pass (2048-bit key) header.d=linaro.org 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 gTWTjI0yla2q for ; Wed, 2 Mar 2022 14:57:33 +0000 (UTC) X-Greylist: whitelisted by SQLgrey-1.8.0 Received: from mail-wm1-x32d.google.com (mail-wm1-x32d.google.com [IPv6:2a00:1450:4864:20::32d]) by smtp4.osuosl.org (Postfix) with ESMTPS id 8A69C402F9 for ; Wed, 2 Mar 2022 14:57:33 +0000 (UTC) Received: by mail-wm1-x32d.google.com with SMTP id 19so1028897wmy.3 for ; Wed, 02 Mar 2022 06:57:33 -0800 (PST) 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=wGGyr8F/4yesRnDkleDkSeBi9/XbD7YGJTcIBLykmxo=; b=YAWW5HKlB7Eey/hbn/tEyKoY+Ej9P8bjmKwFJpG4WIH2K/pus2hP+RvzIjDv6V3z5p k6x5v3LHFzzK0yNYVc3/6rqsj7QQzSFP9PqTvboq8Gd2h2U5akBPL3gjR8Gis5rXW7a5 f5Wj0QWjydNWVbiao3cyHkss6w5fRltrK3+kbwT6yAe/CdOFs42vPOp9Mksavp1FhfDg b+8kmdCZBXU7N1sbqbnIx9h7JeO+bMDEWXRboAhQXSO6FrQS9Y2kIONVMIQBVPZeWrO0 GsIgMsxoTCsl6Mtqj6TTCwunX0DqqFgLwCazwzkBeT0HF1oYRmofMt0ZOyXz8dF5vh/a nxAQ== 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=wGGyr8F/4yesRnDkleDkSeBi9/XbD7YGJTcIBLykmxo=; b=Z0dQ2KuhOyK9UA0Y5kyTTHeP2U6rKlNCTO3VqAWk8UVsqtJCGqtFRNmNfuU//ttILd xww6QIWtoswL+R7pynzWh37r5+uydB1IIUVf1Gfh8HbVSmiG5KGRrdcvHkdhAbxTA2H2 8y+1FItghCWNH5OjrLbC/yfEm+fLu6gABFxFNZlZEw5rMnMHgIdUo4NR4+Uw3J+LOW7x u2rRZq57XFaXf6Jg8Lf38A4o5SlLt0moGT9Z1xbBbdFpFx5yM8VVevxslzg9TqHck+gF sdVUVi0GcJIUPky7/JhPRcYvk+5DSvD9VRbmhugTili4crKHIC66Hngq4tBBPxu2kAk2 vaMQ== X-Gm-Message-State: AOAM530ok78pL49yenT0pBgefNAJCpinfInoHAXxcfny35onNUzaxp0y txZgPPO2xRrCqlJbYTd2of6VPQ== X-Google-Smtp-Source: ABdhPJxDjgY35zlNFNM4bX0OTXrJd0JfiswPqCzf7heVkctOxPWyBqq7cmIrMgVAjnLfYiYdzW+RlQ== X-Received: by 2002:a05:600c:40cf:b0:381:1f87:84c4 with SMTP id m15-20020a05600c40cf00b003811f8784c4mr102404wmh.181.1646233051757; Wed, 02 Mar 2022 06:57:31 -0800 (PST) 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 o204-20020a1ca5d5000000b0038331f2f951sm4751221wme.0.2022.03.02.06.57.27 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 02 Mar 2022 06:57:31 -0800 (PST) Date: Wed, 2 Mar 2022 14:57:26 +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: <20220302075421.2131221-1-lee.jones@linaro.org> <20220302082021-mutt-send-email-mst@kernel.org> <20220302095045-mutt-send-email-mst@kernel.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20220302095045-mutt-send-email-mst@kernel.org> Cc: syzbot+adc3cb32385586bec859@syzkaller.appspotmail.com, 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" T24gV2VkLCAwMiBNYXIgMjAyMiwgTWljaGFlbCBTLiBUc2lya2luIHdyb3RlOgoKPiBPbiBXZWQs IE1hciAwMiwgMjAyMiBhdCAwMTo1NjozNVBNICswMDAwLCBMZWUgSm9uZXMgd3JvdGU6Cj4gPiBP biBXZWQsIDAyIE1hciAyMDIyLCBNaWNoYWVsIFMuIFRzaXJraW4gd3JvdGU6Cj4gPiAKPiA+ID4g T24gV2VkLCBNYXIgMDIsIDIwMjIgYXQgMDc6NTQ6MjFBTSArMDAwMCwgTGVlIEpvbmVzIHdyb3Rl Ogo+ID4gPiA+IHZob3N0X3Zzb2NrX2hhbmRsZV90eF9raWNrKCkgYWxyZWFkeSBob2xkcyB0aGUg bXV0ZXggZHVyaW5nIGl0cyBjYWxsCj4gPiA+ID4gdG8gdmhvc3RfZ2V0X3ZxX2Rlc2MoKS4gIEFs bCB3ZSBoYXZlIHRvIGRvIGlzIHRha2UgdGhlIHNhbWUgbG9jawo+ID4gPiA+IGR1cmluZyB2aXJ0 cXVldWUgY2xlYW4tdXAgYW5kIHdlIG1pdGlnYXRlIHRoZSByZXBvcnRlZCBpc3N1ZXMuCj4gPiA+ ID4gCj4gPiA+ID4gTGluazogaHR0cHM6Ly9zeXprYWxsZXIuYXBwc3BvdC5jb20vYnVnP2V4dGlk PTI3OTQzMmQzMGQ4MjVlNjNiYTAwCj4gPiA+ID4gCj4gPiA+ID4gQ2M6IDxzdGFibGVAdmdlci5r ZXJuZWwub3JnPgo+ID4gPiA+IFJlcG9ydGVkLWJ5OiBzeXpib3QrYWRjM2NiMzIzODU1ODZiZWM4 NTlAc3l6a2FsbGVyLmFwcHNwb3RtYWlsLmNvbQo+ID4gPiA+IFNpZ25lZC1vZmYtYnk6IExlZSBK b25lcyA8bGVlLmpvbmVzQGxpbmFyby5vcmc+Cj4gPiA+ID4gLS0tCj4gPiA+ID4gIGRyaXZlcnMv dmhvc3Qvdmhvc3QuYyB8IDIgKysKPiA+ID4gPiAgMSBmaWxlIGNoYW5nZWQsIDIgaW5zZXJ0aW9u cygrKQo+ID4gPiA+IAo+ID4gPiA+IGRpZmYgLS1naXQgYS9kcml2ZXJzL3Zob3N0L3Zob3N0LmMg Yi9kcml2ZXJzL3Zob3N0L3Zob3N0LmMKPiA+ID4gPiBpbmRleCA1OWVkYjVhMWZmZTI4Li5iYmFm ZjZhNWUyMWI4IDEwMDY0NAo+ID4gPiA+IC0tLSBhL2RyaXZlcnMvdmhvc3Qvdmhvc3QuYwo+ID4g PiA+ICsrKyBiL2RyaXZlcnMvdmhvc3Qvdmhvc3QuYwo+ID4gPiA+IEBAIC02OTMsNiArNjkzLDcg QEAgdm9pZCB2aG9zdF9kZXZfY2xlYW51cChzdHJ1Y3Qgdmhvc3RfZGV2ICpkZXYpCj4gPiA+ID4g IAlpbnQgaTsKPiA+ID4gPiAgCj4gPiA+ID4gIAlmb3IgKGkgPSAwOyBpIDwgZGV2LT5udnFzOyAr K2kpIHsKPiA+ID4gPiArCQltdXRleF9sb2NrKCZkZXYtPnZxc1tpXS0+bXV0ZXgpOwo+ID4gPiA+ ICAJCWlmIChkZXYtPnZxc1tpXS0+ZXJyb3JfY3R4KQo+ID4gPiA+ICAJCQlldmVudGZkX2N0eF9w dXQoZGV2LT52cXNbaV0tPmVycm9yX2N0eCk7Cj4gPiA+ID4gIAkJaWYgKGRldi0+dnFzW2ldLT5r aWNrKQo+ID4gPiA+IEBAIC03MDAsNiArNzAxLDcgQEAgdm9pZCB2aG9zdF9kZXZfY2xlYW51cChz dHJ1Y3Qgdmhvc3RfZGV2ICpkZXYpCj4gPiA+ID4gIAkJaWYgKGRldi0+dnFzW2ldLT5jYWxsX2N0 eC5jdHgpCj4gPiA+ID4gIAkJCWV2ZW50ZmRfY3R4X3B1dChkZXYtPnZxc1tpXS0+Y2FsbF9jdHgu Y3R4KTsKPiA+ID4gPiAgCQl2aG9zdF92cV9yZXNldChkZXYsIGRldi0+dnFzW2ldKTsKPiA+ID4g PiArCQltdXRleF91bmxvY2soJmRldi0+dnFzW2ldLT5tdXRleCk7Cj4gPiA+ID4gIAl9Cj4gPiA+ IAo+ID4gPiBTbyB0aGlzIGlzIGEgbWl0aWdhdGlvbiBwbGFuIGJ1dCB0aGUgYnVnIGlzIHN0aWxs IHRoZXJlIHRob3VnaAo+ID4gPiB3ZSBkb24ndCBrbm93IGV4YWN0bHkgd2hhdCBpdCBpcy4gIEkg d291bGQgcHJlZmVyIGFkZGluZyBzb21ldGhpbmcgbGlrZQo+ID4gPiBXQVJOX09OKG11dGV4X2lz X2xvY2tlZCh2cXNbaV0tPm11dGV4KSBoZXJlIC0gZG9lcyB0aGlzIG1ha2Ugc2Vuc2U/Cj4gPiAK PiA+IEFzIGEgcmV3b3JrIHRvIHRoaXMsIG9yIGFzIGEgc3Vic2VxdWVudCBwYXRjaD8KPiAKPiBD YW4gYmUgYSBzZXBhcmF0ZSBwYXRjaC4KPiAKPiA+IEp1c3QgYmVmb3JlIHRoZSBmaXJzdCBsb2Nr IEkgYXNzdW1lPwo+IAo+IEkgZ3Vlc3Mgc28sIHllcy4KCk5vIHByb2JsZW0uICBQYXRjaCB0byBm b2xsb3cuCgpJJ20gYWxzbyBnb2luZyB0byBhdHRlbXB0IHRvIGRlYnVnIHRoZSByb290IGNhdXNl LCBidXQgSSdtIG5ldyB0byB0aGlzCnN1YnN5c3RlbSB0byBpdCBtaWdodCB0YWtlIGEgd2hpbGUg Zm9yIG1lIHRvIGdldCBteSBoZWFkIGFyb3VuZC4KCi0tIApMZWUgSm9uZXMgW+adjueQvOaWr10K UHJpbmNpcGFsIFRlY2huaWNhbCBMZWFkIC0gRGV2ZWxvcGVyIFNlcnZpY2VzCkxpbmFyby5vcmcg 4pSCIE9wZW4gc291cmNlIHNvZnR3YXJlIGZvciBBcm0gU29DcwpGb2xsb3cgTGluYXJvOiBGYWNl Ym9vayB8IFR3aXR0ZXIgfCBCbG9nCl9fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19f X19fX19fX19fX19fClZpcnR1YWxpemF0aW9uIG1haWxpbmcgbGlzdApWaXJ0dWFsaXphdGlvbkBs aXN0cy5saW51eC1mb3VuZGF0aW9uLm9yZwpodHRwczovL2xpc3RzLmxpbnV4Zm91bmRhdGlvbi5v cmcvbWFpbG1hbi9saXN0aW5mby92aXJ0dWFsaXphdGlvbg==