From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jason Wang Subject: Re: Shutting down a VM with Kernel 4.14 will sometime hang and a reboot is the only way to recover. Date: Wed, 29 Nov 2017 13:15:55 +0800 Message-ID: <918c4152-bcf9-b28c-0f54-f51d07d82bfc@redhat.com> References: <92c4f997-80db-fabf-98c8-fcb92da064a7@redhat.com> <7bd45f84-d07e-7fca-6ca3-07dededd092d@redhat.com> <29f8e09f-8920-52d0-02f4-c0fb779135ee@redhat.com> <9c912f3b-081c-8b02-17c8-453ebf36f42c@redhat.com> <10fe2b98-1e26-9539-9f49-0d01f8693e04@redhat.com> <6b41b4e5-6c0c-fce6-21fe-02dd8f550095@redhat.com> <634116a6-6338-4249-7d2d-430b654cc99c@redhat.com> <1f789868-7fda-3553-7078-3298873fb355@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit To: Dave Hill , Paolo Bonzini , kvm@vger.kernel.org Return-path: Received: from mx1.redhat.com ([209.132.183.28]:35098 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750778AbdK2FQK (ORCPT ); Wed, 29 Nov 2017 00:16:10 -0500 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id ACB9EA7E3 for ; Wed, 29 Nov 2017 05:16:10 +0000 (UTC) In-Reply-To: <1f789868-7fda-3553-7078-3298873fb355@redhat.com> Content-Language: en-US Sender: kvm-owner@vger.kernel.org List-ID: On 2017年11月29日 10:52, Dave Hill wrote: >>> >> >> Thanks. Zerocopy is disabled by several distribution by default. For >> upstream, the only reason to let it on is to hope more developers can >> help and fix the issues. >> >> > So I never hit this issue with previous kernel and this issue started > happening with the v4.14-rc series. Right, this still need to be investigated if it was introduced recently. Looking at git history, the only suspected commit is for 4.14 is commit 1e6f74536de08b5e50cf0e37e735911c2cef7c62 Author: Willem de Bruijn Date:   Fri Oct 6 13:22:31 2017 -0400     vhost_net: do not stall on zerocopy depletion Maybe you can try to revert it and see. If it does not solve your issue, I suspect there's bug elsewhere that cause a packet to be held for very long time. >   I'm using rawhide so perhaps this is why it isn't disabled by > default but I have to mention it's an update of FC25 up to FC28 and it > never got disabled. > Perhaps it should be disabled in Fedora too if it's not the case... > I'm not sure this is the place to discuss this ... is it? Probably not, but I guess Fedora tries to use new technology aggressively. Thanks