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: Thu, 30 Nov 2017 10:42:34 +0800 Message-ID: <68b5d4aa-1d48-d9a1-fc47-62ee8d7ad07a@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> <918c4152-bcf9-b28c-0f54-f51d07d82bfc@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit To: David Hill , Paolo Bonzini , kvm@vger.kernel.org Return-path: Received: from mx1.redhat.com ([209.132.183.28]:43914 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752506AbdK3Cmi (ORCPT ); Wed, 29 Nov 2017 21:42:38 -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 7D394C0587D9 for ; Thu, 30 Nov 2017 02:42:38 +0000 (UTC) In-Reply-To: Content-Language: en-US Sender: kvm-owner@vger.kernel.org List-ID: On 2017年11月30日 03:13, David Hill wrote: > > > On 2017-11-29 12:15 AM, Jason Wang wrote: >> >> >> 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 > > I can revert that commit in 4.15-rc1 but I can't find it in 4.14.2 > ...  Is there another commit that could affect this ? My bad, the suspicious is then: 1f8b977ab32dc5d148f103326e80d9097f1cefb5 ("sock: enable MSG_ZEROCOPY") c1d1b437816f0afa99202be3cb650c9d174667bc ("net: convert (struct ubuf_info)->refcnt to refcount_t") Thanks