From owner-freebsd-xen@freebsd.org Tue Mar 16 07:06:37 2021 Return-Path: Delivered-To: freebsd-xen@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id 59A655798C6 for ; Tue, 16 Mar 2021 07:06:37 +0000 (UTC) (envelope-from buhrow@nfbcal.org) Received: from nfbcal.org (ns.NFBCAL.ORG [157.22.230.125]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "nfbcal.org", Issuer "R3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4F048W60vbz3NFV for ; Tue, 16 Mar 2021 07:06:35 +0000 (UTC) (envelope-from buhrow@nfbcal.org) Received: from nfbcal.org (localhost [127.0.0.1]) by nfbcal.org (8.15.2/8.14.1-NFBNETBSD) with ESMTPS id 12G76W3A012981 (version=TLSv1.2 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Tue, 16 Mar 2021 00:06:32 -0700 (PDT) Received: (from buhrow@localhost) by nfbcal.org (8.15.2/8.12.11) id 12G76WLQ014062; Tue, 16 Mar 2021 00:06:32 -0700 (PDT) Message-Id: <202103160706.12G76WLQ014062@nfbcal.org> From: Brian Buhrow Date: Tue, 16 Mar 2021 00:06:32 -0700 In-Reply-To: <202103152124.12FLOeeg004469@nfbcal.org> X-Mailer: Mail User's Shell (7.2.6 beta(4.pl1)+dynamic 20000103) To: freebsd-xen@freebsd.org Subject: Re: Corruption in xenstored tdb file? X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.4.3 (nfbcal.org [127.0.0.1]); Tue, 16 Mar 2021 00:06:32 -0700 (PDT) X-Rspamd-Queue-Id: 4F048W60vbz3NFV X-Spamd-Bar: -- Authentication-Results: mx1.freebsd.org; dkim=none; dmarc=none; spf=pass (mx1.freebsd.org: domain of buhrow@nfbcal.org designates 157.22.230.125 as permitted sender) smtp.mailfrom=buhrow@nfbcal.org X-Spamd-Result: default: False [-2.30 / 15.00]; SUBJECT_ENDS_QUESTION(1.00)[]; RBL_DBL_DONT_QUERY_IPS(0.00)[157.22.230.125:from]; RCVD_TLS_ALL(0.00)[]; FROM_HAS_DN(0.00)[]; R_SPF_ALLOW(-0.20)[+a:ns.nfbcal.org]; MID_RHS_MATCH_FROM(0.00)[]; MIME_GOOD(-0.10)[text/plain]; TO_DN_NONE(0.00)[]; ARC_NA(0.00)[]; DMARC_NA(0.00)[nfbcal.org]; SPAMHAUS_ZRD(0.00)[157.22.230.125:from:127.0.2.255]; TO_MATCH_ENVRCPT_SOME(0.00)[]; NEURAL_HAM_LONG(-1.00)[-1.000]; RCPT_COUNT_TWO(0.00)[2]; NEURAL_HAM_SHORT(-1.00)[-1.000]; NEURAL_HAM_MEDIUM(-1.00)[-1.000]; FROM_EQ_ENVFROM(0.00)[]; R_DKIM_NA(0.00)[]; MIME_TRACE(0.00)[0:+]; RCVD_COUNT_TWO(0.00)[2]; ASN(0.00)[asn:7091, ipnet:157.22.0.0/16, country:US]; MAILMAN_DEST(0.00)[freebsd-xen] X-BeenThere: freebsd-xen@freebsd.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Discussion of the freebsd port to xen - implementation and usage List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 16 Mar 2021 07:06:37 -0000 hello. Following up on this further, it seems there may be a timing issue related to this after all. If I bring up a NetBSD-5.2 VM, the VM comes up without a problem and xennet0 works just as it should. I can do this time and time again without any trouble. However, if I bring up a NetBSD-99.77 (current as of January 28 2021), I get the behavior I described in the previous message. It's obviously some kind of race condition, since if I reboot the NetBSD-current VM several times, I can get it to come up with a network interface occasionally. However, not enough to make it usable. Also, since I wrote last, I updated to 12.2-release--p4, just to see if that made things better. It did not. I suspect, but don't know for sure, that the issue is that NetBSD-current is issuing commands on the xenbus faster than it did in NetBSD-5. If that's true, then I think the problem lies with FreeBSD, as, in my view, a VM guest shouldn't be able to trigger a race condition in the host side of the server, which is what appears to be happening here. Is there a way to get a trace of the communications between the domU's and the dom0 so I can see the differences between what NetBSD used to do and what it does today? -thanks -Brian