Re: port-xen/59745: guest network hosed, host says: xvif6i0 GNTTABOP_copy[0] Rx -3

[Manuel Bouyer <bouyer%antioche.eu.org@localhost>]

The following reply was made to PR port-xen/59745; it has been noted by GNATS.

From: Manuel Bouyer <bouyer%antioche.eu.org@localhost>
To: gnats-bugs%netbsd.org@localhost
Cc: port-xen-maintainer%netbsd.org@localhost, gnats-admin%netbsd.org@localhost,
        netbsd-bugs%netbsd.org@localhost
Subject: Re: port-xen/59745: guest network hosed, host says: xvif6i0
 GNTTABOP_copy[0] Rx -3
Date: Mon, 3 Nov 2025 11:31:44 +0100

 On Mon, Nov 03, 2025 at 01:25:00AM +0000, campbell+netbsd%mumble.net@localhost wrote:
 > >Number:         59745
 > >Category:       port-xen
 > >Synopsis:       guest network hosed, host says: xvif6i0 GNTTABOP_copy[0] Rx -3
 > >Confidential:   no
 > >Severity:       serious
 > >Priority:       medium
 > >Responsible:    port-xen-maintainer
 > >State:          open
 > >Class:          sw-bug
 > >Submitter-Id:   net
 > >Arrival-Date:   Mon Nov 03 01:25:00 +0000 2025
 > >Originator:     Taylor R Campbell
 > >Release:        10.1_STABLE
 > >Organization:
 > The GrantBSD Foundabop
 > >Environment:
 > NetBSD cole.netbsd.de 10.1_STABLE NetBSD 10.1_STABLE (TNF_XENSERVER_PVH) #1: Sat Oct  4 22:20:13 UTC 2025  spz%franklin.NetBSD.org@localhost:/home/netbsd/10/amd64/obj/sys/arch/amd64/compile/TNF_XENSERVER_PVH amd64
 > >Description:
 > 
 > 	In two incidents recently, we've had a guest on TNF
 > 	infrastructure become unreachable over the network -- no
 > 	response to pings or TCP connections, nothing logged in
 > 	npflog0, system mainly idle.
 > 
 > 	The host's dmesg is full of messages like this:
 > 
 > [ 2451339.802864] xvif6i0 GNTTABOP_copy[0] Rx -3
 > [ 2451339.802864] xvif6i0 GNTTABOP_copy[0] Rx -3
 > [ 2451339.802864] xvif6i0 GNTTABOP_copy[0] Rx -3
 > [ 2451339.802864] xvif6i0 GNTTABOP_copy[0] Rx -3
 > [ 2451339.802864] xvif6i0 GNTTABOP_copy[0] Rx -3
 > [ 2451339.802864] xvif6i0 GNTTABOP_copy[0] Rx -3
 > 
 > 	That's this message:
 > 
 >     638 	/*
 >     639 	 * Copy the data and ack it. Delaying it until the mbuf is
 >     640 	 * freed will stall transmit.
 >     641 	 */
 >     642 	if (HYPERVISOR_grant_table_op(GNTTABOP_copy, gop, copycnt) != 0) {
 >     643 		printf("%s: GNTTABOP_copy %s failed", ifp->if_xname, dir);
 >     644 		return EINVAL;
 >     645 	}
 
 Are you running a debug hypervisor (xen-debug.gz from the package) ?
 If so, does anything shows up in xl dmesg or on serial console ?
 
 Also you don't mention the xen version
 
 -- 
 Manuel Bouyer <bouyer%antioche.eu.org@localhost>
      NetBSD: 26 ans d'experience feront toujours la difference
 --