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Diffstat (limited to 'results/classifier/014/all/80604314')
| -rw-r--r-- | results/classifier/014/all/80604314 | 1507 |
1 files changed, 1507 insertions, 0 deletions
diff --git a/results/classifier/014/all/80604314 b/results/classifier/014/all/80604314 new file mode 100644 index 000000000..0a909535e --- /dev/null +++ b/results/classifier/014/all/80604314 @@ -0,0 +1,1507 @@ +TCG: 0.923 +mistranslation: 0.922 +performance: 0.919 +device: 0.917 +peripherals: 0.905 +VMM: 0.902 +debug: 0.901 +graphic: 0.901 +operating system: 0.900 +ppc: 0.900 +PID: 0.896 +permissions: 0.892 +KVM: 0.891 +semantic: 0.890 +architecture: 0.888 +user-level: 0.887 +assembly: 0.886 +socket: 0.884 +register: 0.881 +vnc: 0.881 +risc-v: 0.880 +hypervisor: 0.877 +arm: 0.869 +network: 0.865 +files: 0.861 +virtual: 0.861 +boot: 0.860 +kernel: 0.850 +alpha: 0.834 +x86: 0.828 +i386: 0.765 + +[BUG] vhost-vdpa: qemu-system-s390x crashes with second virtio-net-ccw device + +When I start qemu with a second virtio-net-ccw device (i.e. adding +-device virtio-net-ccw in addition to the autogenerated device), I get +a segfault. gdb points to + +#0 0x000055d6ab52681d in virtio_net_get_config (vdev=<optimized out>, + config=0x55d6ad9e3f80 "RT") at /home/cohuck/git/qemu/hw/net/virtio-net.c:146 +146 if (nc->peer->info->type == NET_CLIENT_DRIVER_VHOST_VDPA) { + +(backtrace doesn't go further) + +Starting qemu with no additional "-device virtio-net-ccw" (i.e., only +the autogenerated virtio-net-ccw device is present) works. Specifying +several "-device virtio-net-pci" works as well. + +Things break with 1e0a84ea49b6 ("vhost-vdpa: introduce vhost-vdpa net +client"), 38140cc4d971 ("vhost_net: introduce set_config & get_config") +works (in-between state does not compile). + +This is reproducible with tcg as well. Same problem both with +--enable-vhost-vdpa and --disable-vhost-vdpa. + +Have not yet tried to figure out what might be special with +virtio-ccw... anyone have an idea? + +[This should probably be considered a blocker?] + +On Fri, Jul 24, 2020 at 03:27:18PM +0200, Cornelia Huck wrote: +> +When I start qemu with a second virtio-net-ccw device (i.e. adding +> +-device virtio-net-ccw in addition to the autogenerated device), I get +> +a segfault. gdb points to +> +> +#0 0x000055d6ab52681d in virtio_net_get_config (vdev=<optimized out>, +> +config=0x55d6ad9e3f80 "RT") at +> +/home/cohuck/git/qemu/hw/net/virtio-net.c:146 +> +146 if (nc->peer->info->type == NET_CLIENT_DRIVER_VHOST_VDPA) { +> +> +(backtrace doesn't go further) +> +> +Starting qemu with no additional "-device virtio-net-ccw" (i.e., only +> +the autogenerated virtio-net-ccw device is present) works. Specifying +> +several "-device virtio-net-pci" works as well. +> +> +Things break with 1e0a84ea49b6 ("vhost-vdpa: introduce vhost-vdpa net +> +client"), 38140cc4d971 ("vhost_net: introduce set_config & get_config") +> +works (in-between state does not compile). +Ouch. I didn't test all in-between states :( +But I wish we had a 0-day instrastructure like kernel has, +that catches things like that. + +> +This is reproducible with tcg as well. Same problem both with +> +--enable-vhost-vdpa and --disable-vhost-vdpa. +> +> +Have not yet tried to figure out what might be special with +> +virtio-ccw... anyone have an idea? +> +> +[This should probably be considered a blocker?] + +On Fri, 24 Jul 2020 09:30:58 -0400 +"Michael S. Tsirkin" <mst@redhat.com> wrote: + +> +On Fri, Jul 24, 2020 at 03:27:18PM +0200, Cornelia Huck wrote: +> +> When I start qemu with a second virtio-net-ccw device (i.e. adding +> +> -device virtio-net-ccw in addition to the autogenerated device), I get +> +> a segfault. gdb points to +> +> +> +> #0 0x000055d6ab52681d in virtio_net_get_config (vdev=<optimized out>, +> +> config=0x55d6ad9e3f80 "RT") at +> +> /home/cohuck/git/qemu/hw/net/virtio-net.c:146 +> +> 146 if (nc->peer->info->type == NET_CLIENT_DRIVER_VHOST_VDPA) { +> +> +> +> (backtrace doesn't go further) +The core was incomplete, but running under gdb directly shows that it +is just a bog-standard config space access (first for that device). + +The cause of the crash is that nc->peer is not set... no idea how that +can happen, not that familiar with that part of QEMU. (Should the code +check, or is that really something that should not happen?) + +What I don't understand is why it is set correctly for the first, +autogenerated virtio-net-ccw device, but not for the second one, and +why virtio-net-pci doesn't show these problems. The only difference +between -ccw and -pci that comes to my mind here is that config space +accesses for ccw are done via an asynchronous operation, so timing +might be different. + +> +> +> +> Starting qemu with no additional "-device virtio-net-ccw" (i.e., only +> +> the autogenerated virtio-net-ccw device is present) works. Specifying +> +> several "-device virtio-net-pci" works as well. +> +> +> +> Things break with 1e0a84ea49b6 ("vhost-vdpa: introduce vhost-vdpa net +> +> client"), 38140cc4d971 ("vhost_net: introduce set_config & get_config") +> +> works (in-between state does not compile). +> +> +Ouch. I didn't test all in-between states :( +> +But I wish we had a 0-day instrastructure like kernel has, +> +that catches things like that. +Yep, that would be useful... so patchew only builds the complete series? + +> +> +> This is reproducible with tcg as well. Same problem both with +> +> --enable-vhost-vdpa and --disable-vhost-vdpa. +> +> +> +> Have not yet tried to figure out what might be special with +> +> virtio-ccw... anyone have an idea? +> +> +> +> [This should probably be considered a blocker?] +I think so, as it makes s390x unusable with more that one +virtio-net-ccw device, and I don't even see a workaround. + +On Fri, Jul 24, 2020 at 04:56:27PM +0200, Cornelia Huck wrote: +> +On Fri, 24 Jul 2020 09:30:58 -0400 +> +"Michael S. Tsirkin" <mst@redhat.com> wrote: +> +> +> On Fri, Jul 24, 2020 at 03:27:18PM +0200, Cornelia Huck wrote: +> +> > When I start qemu with a second virtio-net-ccw device (i.e. adding +> +> > -device virtio-net-ccw in addition to the autogenerated device), I get +> +> > a segfault. gdb points to +> +> > +> +> > #0 0x000055d6ab52681d in virtio_net_get_config (vdev=<optimized out>, +> +> > config=0x55d6ad9e3f80 "RT") at +> +> > /home/cohuck/git/qemu/hw/net/virtio-net.c:146 +> +> > 146 if (nc->peer->info->type == NET_CLIENT_DRIVER_VHOST_VDPA) { +> +> > +> +> > (backtrace doesn't go further) +> +> +The core was incomplete, but running under gdb directly shows that it +> +is just a bog-standard config space access (first for that device). +> +> +The cause of the crash is that nc->peer is not set... no idea how that +> +can happen, not that familiar with that part of QEMU. (Should the code +> +check, or is that really something that should not happen?) +> +> +What I don't understand is why it is set correctly for the first, +> +autogenerated virtio-net-ccw device, but not for the second one, and +> +why virtio-net-pci doesn't show these problems. The only difference +> +between -ccw and -pci that comes to my mind here is that config space +> +accesses for ccw are done via an asynchronous operation, so timing +> +might be different. +Hopefully Jason has an idea. Could you post a full command line +please? Do you need a working guest to trigger this? Does this trigger +on an x86 host? + +> +> > +> +> > Starting qemu with no additional "-device virtio-net-ccw" (i.e., only +> +> > the autogenerated virtio-net-ccw device is present) works. Specifying +> +> > several "-device virtio-net-pci" works as well. +> +> > +> +> > Things break with 1e0a84ea49b6 ("vhost-vdpa: introduce vhost-vdpa net +> +> > client"), 38140cc4d971 ("vhost_net: introduce set_config & get_config") +> +> > works (in-between state does not compile). +> +> +> +> Ouch. I didn't test all in-between states :( +> +> But I wish we had a 0-day instrastructure like kernel has, +> +> that catches things like that. +> +> +Yep, that would be useful... so patchew only builds the complete series? +> +> +> +> +> > This is reproducible with tcg as well. Same problem both with +> +> > --enable-vhost-vdpa and --disable-vhost-vdpa. +> +> > +> +> > Have not yet tried to figure out what might be special with +> +> > virtio-ccw... anyone have an idea? +> +> > +> +> > [This should probably be considered a blocker?] +> +> +I think so, as it makes s390x unusable with more that one +> +virtio-net-ccw device, and I don't even see a workaround. + +On Fri, 24 Jul 2020 11:17:57 -0400 +"Michael S. Tsirkin" <mst@redhat.com> wrote: + +> +On Fri, Jul 24, 2020 at 04:56:27PM +0200, Cornelia Huck wrote: +> +> On Fri, 24 Jul 2020 09:30:58 -0400 +> +> "Michael S. Tsirkin" <mst@redhat.com> wrote: +> +> +> +> > On Fri, Jul 24, 2020 at 03:27:18PM +0200, Cornelia Huck wrote: +> +> > > When I start qemu with a second virtio-net-ccw device (i.e. adding +> +> > > -device virtio-net-ccw in addition to the autogenerated device), I get +> +> > > a segfault. gdb points to +> +> > > +> +> > > #0 0x000055d6ab52681d in virtio_net_get_config (vdev=<optimized out>, +> +> > > config=0x55d6ad9e3f80 "RT") at +> +> > > /home/cohuck/git/qemu/hw/net/virtio-net.c:146 +> +> > > 146 if (nc->peer->info->type == NET_CLIENT_DRIVER_VHOST_VDPA) { +> +> > > +> +> > > (backtrace doesn't go further) +> +> +> +> The core was incomplete, but running under gdb directly shows that it +> +> is just a bog-standard config space access (first for that device). +> +> +> +> The cause of the crash is that nc->peer is not set... no idea how that +> +> can happen, not that familiar with that part of QEMU. (Should the code +> +> check, or is that really something that should not happen?) +> +> +> +> What I don't understand is why it is set correctly for the first, +> +> autogenerated virtio-net-ccw device, but not for the second one, and +> +> why virtio-net-pci doesn't show these problems. The only difference +> +> between -ccw and -pci that comes to my mind here is that config space +> +> accesses for ccw are done via an asynchronous operation, so timing +> +> might be different. +> +> +Hopefully Jason has an idea. Could you post a full command line +> +please? Do you need a working guest to trigger this? Does this trigger +> +on an x86 host? +Yes, it does trigger with tcg-on-x86 as well. I've been using + +s390x-softmmu/qemu-system-s390x -M s390-ccw-virtio,accel=tcg -cpu qemu,zpci=on +-m 1024 -nographic -device virtio-scsi-ccw,id=scsi0,devno=fe.0.0001 +-drive file=/path/to/image,format=qcow2,if=none,id=drive-scsi0-0-0-0 +-device +scsi-hd,bus=scsi0.0,channel=0,scsi-id=0,lun=0,drive=drive-scsi0-0-0-0,id=scsi0-0-0-0,bootindex=1 + +-device virtio-net-ccw + +It seems it needs the guest actually doing something with the nics; I +cannot reproduce the crash if I use the old advent calendar moon buggy +image and just add a virtio-net-ccw device. + +(I don't think it's a problem with my local build, as I see the problem +both on my laptop and on an LPAR.) + +> +> +> > > +> +> > > Starting qemu with no additional "-device virtio-net-ccw" (i.e., only +> +> > > the autogenerated virtio-net-ccw device is present) works. Specifying +> +> > > several "-device virtio-net-pci" works as well. +> +> > > +> +> > > Things break with 1e0a84ea49b6 ("vhost-vdpa: introduce vhost-vdpa net +> +> > > client"), 38140cc4d971 ("vhost_net: introduce set_config & get_config") +> +> > > works (in-between state does not compile). +> +> > +> +> > Ouch. I didn't test all in-between states :( +> +> > But I wish we had a 0-day instrastructure like kernel has, +> +> > that catches things like that. +> +> +> +> Yep, that would be useful... so patchew only builds the complete series? +> +> +> +> > +> +> > > This is reproducible with tcg as well. Same problem both with +> +> > > --enable-vhost-vdpa and --disable-vhost-vdpa. +> +> > > +> +> > > Have not yet tried to figure out what might be special with +> +> > > virtio-ccw... anyone have an idea? +> +> > > +> +> > > [This should probably be considered a blocker?] +> +> +> +> I think so, as it makes s390x unusable with more that one +> +> virtio-net-ccw device, and I don't even see a workaround. +> + +On 2020/7/24 ä¸å11:34, Cornelia Huck wrote: +On Fri, 24 Jul 2020 11:17:57 -0400 +"Michael S. Tsirkin"<mst@redhat.com> wrote: +On Fri, Jul 24, 2020 at 04:56:27PM +0200, Cornelia Huck wrote: +On Fri, 24 Jul 2020 09:30:58 -0400 +"Michael S. Tsirkin"<mst@redhat.com> wrote: +On Fri, Jul 24, 2020 at 03:27:18PM +0200, Cornelia Huck wrote: +When I start qemu with a second virtio-net-ccw device (i.e. adding +-device virtio-net-ccw in addition to the autogenerated device), I get +a segfault. gdb points to + +#0 0x000055d6ab52681d in virtio_net_get_config (vdev=<optimized out>, + config=0x55d6ad9e3f80 "RT") at +/home/cohuck/git/qemu/hw/net/virtio-net.c:146 +146 if (nc->peer->info->type == NET_CLIENT_DRIVER_VHOST_VDPA) { + +(backtrace doesn't go further) +The core was incomplete, but running under gdb directly shows that it +is just a bog-standard config space access (first for that device). + +The cause of the crash is that nc->peer is not set... no idea how that +can happen, not that familiar with that part of QEMU. (Should the code +check, or is that really something that should not happen?) + +What I don't understand is why it is set correctly for the first, +autogenerated virtio-net-ccw device, but not for the second one, and +why virtio-net-pci doesn't show these problems. The only difference +between -ccw and -pci that comes to my mind here is that config space +accesses for ccw are done via an asynchronous operation, so timing +might be different. +Hopefully Jason has an idea. Could you post a full command line +please? Do you need a working guest to trigger this? Does this trigger +on an x86 host? +Yes, it does trigger with tcg-on-x86 as well. I've been using + +s390x-softmmu/qemu-system-s390x -M s390-ccw-virtio,accel=tcg -cpu qemu,zpci=on +-m 1024 -nographic -device virtio-scsi-ccw,id=scsi0,devno=fe.0.0001 +-drive file=/path/to/image,format=qcow2,if=none,id=drive-scsi0-0-0-0 +-device +scsi-hd,bus=scsi0.0,channel=0,scsi-id=0,lun=0,drive=drive-scsi0-0-0-0,id=scsi0-0-0-0,bootindex=1 +-device virtio-net-ccw + +It seems it needs the guest actually doing something with the nics; I +cannot reproduce the crash if I use the old advent calendar moon buggy +image and just add a virtio-net-ccw device. + +(I don't think it's a problem with my local build, as I see the problem +both on my laptop and on an LPAR.) +It looks to me we forget the check the existence of peer. + +Please try the attached patch to see if it works. + +Thanks +0001-virtio-net-check-the-existence-of-peer-before-accesi.patch +Description: +Text Data + +On Sat, 25 Jul 2020 08:40:07 +0800 +Jason Wang <jasowang@redhat.com> wrote: + +> +On 2020/7/24 ä¸å11:34, Cornelia Huck wrote: +> +> On Fri, 24 Jul 2020 11:17:57 -0400 +> +> "Michael S. Tsirkin"<mst@redhat.com> wrote: +> +> +> +>> On Fri, Jul 24, 2020 at 04:56:27PM +0200, Cornelia Huck wrote: +> +>>> On Fri, 24 Jul 2020 09:30:58 -0400 +> +>>> "Michael S. Tsirkin"<mst@redhat.com> wrote: +> +>>> +> +>>>> On Fri, Jul 24, 2020 at 03:27:18PM +0200, Cornelia Huck wrote: +> +>>>>> When I start qemu with a second virtio-net-ccw device (i.e. adding +> +>>>>> -device virtio-net-ccw in addition to the autogenerated device), I get +> +>>>>> a segfault. gdb points to +> +>>>>> +> +>>>>> #0 0x000055d6ab52681d in virtio_net_get_config (vdev=<optimized out>, +> +>>>>> config=0x55d6ad9e3f80 "RT") at +> +>>>>> /home/cohuck/git/qemu/hw/net/virtio-net.c:146 +> +>>>>> 146 if (nc->peer->info->type == NET_CLIENT_DRIVER_VHOST_VDPA) { +> +>>>>> +> +>>>>> (backtrace doesn't go further) +> +>>> The core was incomplete, but running under gdb directly shows that it +> +>>> is just a bog-standard config space access (first for that device). +> +>>> +> +>>> The cause of the crash is that nc->peer is not set... no idea how that +> +>>> can happen, not that familiar with that part of QEMU. (Should the code +> +>>> check, or is that really something that should not happen?) +> +>>> +> +>>> What I don't understand is why it is set correctly for the first, +> +>>> autogenerated virtio-net-ccw device, but not for the second one, and +> +>>> why virtio-net-pci doesn't show these problems. The only difference +> +>>> between -ccw and -pci that comes to my mind here is that config space +> +>>> accesses for ccw are done via an asynchronous operation, so timing +> +>>> might be different. +> +>> Hopefully Jason has an idea. Could you post a full command line +> +>> please? Do you need a working guest to trigger this? Does this trigger +> +>> on an x86 host? +> +> Yes, it does trigger with tcg-on-x86 as well. I've been using +> +> +> +> s390x-softmmu/qemu-system-s390x -M s390-ccw-virtio,accel=tcg -cpu +> +> qemu,zpci=on +> +> -m 1024 -nographic -device virtio-scsi-ccw,id=scsi0,devno=fe.0.0001 +> +> -drive file=/path/to/image,format=qcow2,if=none,id=drive-scsi0-0-0-0 +> +> -device +> +> scsi-hd,bus=scsi0.0,channel=0,scsi-id=0,lun=0,drive=drive-scsi0-0-0-0,id=scsi0-0-0-0,bootindex=1 +> +> -device virtio-net-ccw +> +> +> +> It seems it needs the guest actually doing something with the nics; I +> +> cannot reproduce the crash if I use the old advent calendar moon buggy +> +> image and just add a virtio-net-ccw device. +> +> +> +> (I don't think it's a problem with my local build, as I see the problem +> +> both on my laptop and on an LPAR.) +> +> +> +It looks to me we forget the check the existence of peer. +> +> +Please try the attached patch to see if it works. +Thanks, that patch gets my guest up and running again. So, FWIW, + +Tested-by: Cornelia Huck <cohuck@redhat.com> + +Any idea why this did not hit with virtio-net-pci (or the autogenerated +virtio-net-ccw device)? + +On 2020/7/27 ä¸å2:43, Cornelia Huck wrote: +On Sat, 25 Jul 2020 08:40:07 +0800 +Jason Wang <jasowang@redhat.com> wrote: +On 2020/7/24 ä¸å11:34, Cornelia Huck wrote: +On Fri, 24 Jul 2020 11:17:57 -0400 +"Michael S. Tsirkin"<mst@redhat.com> wrote: +On Fri, Jul 24, 2020 at 04:56:27PM +0200, Cornelia Huck wrote: +On Fri, 24 Jul 2020 09:30:58 -0400 +"Michael S. Tsirkin"<mst@redhat.com> wrote: +On Fri, Jul 24, 2020 at 03:27:18PM +0200, Cornelia Huck wrote: +When I start qemu with a second virtio-net-ccw device (i.e. adding +-device virtio-net-ccw in addition to the autogenerated device), I get +a segfault. gdb points to + +#0 0x000055d6ab52681d in virtio_net_get_config (vdev=<optimized out>, + config=0x55d6ad9e3f80 "RT") at +/home/cohuck/git/qemu/hw/net/virtio-net.c:146 +146 if (nc->peer->info->type == NET_CLIENT_DRIVER_VHOST_VDPA) { + +(backtrace doesn't go further) +The core was incomplete, but running under gdb directly shows that it +is just a bog-standard config space access (first for that device). + +The cause of the crash is that nc->peer is not set... no idea how that +can happen, not that familiar with that part of QEMU. (Should the code +check, or is that really something that should not happen?) + +What I don't understand is why it is set correctly for the first, +autogenerated virtio-net-ccw device, but not for the second one, and +why virtio-net-pci doesn't show these problems. The only difference +between -ccw and -pci that comes to my mind here is that config space +accesses for ccw are done via an asynchronous operation, so timing +might be different. +Hopefully Jason has an idea. Could you post a full command line +please? Do you need a working guest to trigger this? Does this trigger +on an x86 host? +Yes, it does trigger with tcg-on-x86 as well. I've been using + +s390x-softmmu/qemu-system-s390x -M s390-ccw-virtio,accel=tcg -cpu qemu,zpci=on +-m 1024 -nographic -device virtio-scsi-ccw,id=scsi0,devno=fe.0.0001 +-drive file=/path/to/image,format=qcow2,if=none,id=drive-scsi0-0-0-0 +-device +scsi-hd,bus=scsi0.0,channel=0,scsi-id=0,lun=0,drive=drive-scsi0-0-0-0,id=scsi0-0-0-0,bootindex=1 +-device virtio-net-ccw + +It seems it needs the guest actually doing something with the nics; I +cannot reproduce the crash if I use the old advent calendar moon buggy +image and just add a virtio-net-ccw device. + +(I don't think it's a problem with my local build, as I see the problem +both on my laptop and on an LPAR.) +It looks to me we forget the check the existence of peer. + +Please try the attached patch to see if it works. +Thanks, that patch gets my guest up and running again. So, FWIW, + +Tested-by: Cornelia Huck <cohuck@redhat.com> + +Any idea why this did not hit with virtio-net-pci (or the autogenerated +virtio-net-ccw device)? +It can be hit with virtio-net-pci as well (just start without peer). +For autogenerated virtio-net-cww, I think the reason is that it has +already had a peer set. +Thanks + +On Mon, 27 Jul 2020 15:38:12 +0800 +Jason Wang <jasowang@redhat.com> wrote: + +> +On 2020/7/27 ä¸å2:43, Cornelia Huck wrote: +> +> On Sat, 25 Jul 2020 08:40:07 +0800 +> +> Jason Wang <jasowang@redhat.com> wrote: +> +> +> +>> On 2020/7/24 ä¸å11:34, Cornelia Huck wrote: +> +>>> On Fri, 24 Jul 2020 11:17:57 -0400 +> +>>> "Michael S. Tsirkin"<mst@redhat.com> wrote: +> +>>> +> +>>>> On Fri, Jul 24, 2020 at 04:56:27PM +0200, Cornelia Huck wrote: +> +>>>>> On Fri, 24 Jul 2020 09:30:58 -0400 +> +>>>>> "Michael S. Tsirkin"<mst@redhat.com> wrote: +> +>>>>> +> +>>>>>> On Fri, Jul 24, 2020 at 03:27:18PM +0200, Cornelia Huck wrote: +> +>>>>>>> When I start qemu with a second virtio-net-ccw device (i.e. adding +> +>>>>>>> -device virtio-net-ccw in addition to the autogenerated device), I get +> +>>>>>>> a segfault. gdb points to +> +>>>>>>> +> +>>>>>>> #0 0x000055d6ab52681d in virtio_net_get_config (vdev=<optimized out>, +> +>>>>>>> config=0x55d6ad9e3f80 "RT") at +> +>>>>>>> /home/cohuck/git/qemu/hw/net/virtio-net.c:146 +> +>>>>>>> 146 if (nc->peer->info->type == NET_CLIENT_DRIVER_VHOST_VDPA) { +> +>>>>>>> +> +>>>>>>> (backtrace doesn't go further) +> +>>>>> The core was incomplete, but running under gdb directly shows that it +> +>>>>> is just a bog-standard config space access (first for that device). +> +>>>>> +> +>>>>> The cause of the crash is that nc->peer is not set... no idea how that +> +>>>>> can happen, not that familiar with that part of QEMU. (Should the code +> +>>>>> check, or is that really something that should not happen?) +> +>>>>> +> +>>>>> What I don't understand is why it is set correctly for the first, +> +>>>>> autogenerated virtio-net-ccw device, but not for the second one, and +> +>>>>> why virtio-net-pci doesn't show these problems. The only difference +> +>>>>> between -ccw and -pci that comes to my mind here is that config space +> +>>>>> accesses for ccw are done via an asynchronous operation, so timing +> +>>>>> might be different. +> +>>>> Hopefully Jason has an idea. Could you post a full command line +> +>>>> please? Do you need a working guest to trigger this? Does this trigger +> +>>>> on an x86 host? +> +>>> Yes, it does trigger with tcg-on-x86 as well. I've been using +> +>>> +> +>>> s390x-softmmu/qemu-system-s390x -M s390-ccw-virtio,accel=tcg -cpu +> +>>> qemu,zpci=on +> +>>> -m 1024 -nographic -device virtio-scsi-ccw,id=scsi0,devno=fe.0.0001 +> +>>> -drive file=/path/to/image,format=qcow2,if=none,id=drive-scsi0-0-0-0 +> +>>> -device +> +>>> scsi-hd,bus=scsi0.0,channel=0,scsi-id=0,lun=0,drive=drive-scsi0-0-0-0,id=scsi0-0-0-0,bootindex=1 +> +>>> -device virtio-net-ccw +> +>>> +> +>>> It seems it needs the guest actually doing something with the nics; I +> +>>> cannot reproduce the crash if I use the old advent calendar moon buggy +> +>>> image and just add a virtio-net-ccw device. +> +>>> +> +>>> (I don't think it's a problem with my local build, as I see the problem +> +>>> both on my laptop and on an LPAR.) +> +>> +> +>> It looks to me we forget the check the existence of peer. +> +>> +> +>> Please try the attached patch to see if it works. +> +> Thanks, that patch gets my guest up and running again. So, FWIW, +> +> +> +> Tested-by: Cornelia Huck <cohuck@redhat.com> +> +> +> +> Any idea why this did not hit with virtio-net-pci (or the autogenerated +> +> virtio-net-ccw device)? +> +> +> +It can be hit with virtio-net-pci as well (just start without peer). +Hm, I had not been able to reproduce the crash with a 'naked' -device +virtio-net-pci. But checking seems to be the right idea anyway. + +> +> +For autogenerated virtio-net-cww, I think the reason is that it has +> +already had a peer set. +Ok, that might well be. + +On 2020/7/27 ä¸å4:41, Cornelia Huck wrote: +On Mon, 27 Jul 2020 15:38:12 +0800 +Jason Wang <jasowang@redhat.com> wrote: +On 2020/7/27 ä¸å2:43, Cornelia Huck wrote: +On Sat, 25 Jul 2020 08:40:07 +0800 +Jason Wang <jasowang@redhat.com> wrote: +On 2020/7/24 ä¸å11:34, Cornelia Huck wrote: +On Fri, 24 Jul 2020 11:17:57 -0400 +"Michael S. Tsirkin"<mst@redhat.com> wrote: +On Fri, Jul 24, 2020 at 04:56:27PM +0200, Cornelia Huck wrote: +On Fri, 24 Jul 2020 09:30:58 -0400 +"Michael S. Tsirkin"<mst@redhat.com> wrote: +On Fri, Jul 24, 2020 at 03:27:18PM +0200, Cornelia Huck wrote: +When I start qemu with a second virtio-net-ccw device (i.e. adding +-device virtio-net-ccw in addition to the autogenerated device), I get +a segfault. gdb points to + +#0 0x000055d6ab52681d in virtio_net_get_config (vdev=<optimized out>, + config=0x55d6ad9e3f80 "RT") at +/home/cohuck/git/qemu/hw/net/virtio-net.c:146 +146 if (nc->peer->info->type == NET_CLIENT_DRIVER_VHOST_VDPA) { + +(backtrace doesn't go further) +The core was incomplete, but running under gdb directly shows that it +is just a bog-standard config space access (first for that device). + +The cause of the crash is that nc->peer is not set... no idea how that +can happen, not that familiar with that part of QEMU. (Should the code +check, or is that really something that should not happen?) + +What I don't understand is why it is set correctly for the first, +autogenerated virtio-net-ccw device, but not for the second one, and +why virtio-net-pci doesn't show these problems. The only difference +between -ccw and -pci that comes to my mind here is that config space +accesses for ccw are done via an asynchronous operation, so timing +might be different. +Hopefully Jason has an idea. Could you post a full command line +please? Do you need a working guest to trigger this? Does this trigger +on an x86 host? +Yes, it does trigger with tcg-on-x86 as well. I've been using + +s390x-softmmu/qemu-system-s390x -M s390-ccw-virtio,accel=tcg -cpu qemu,zpci=on +-m 1024 -nographic -device virtio-scsi-ccw,id=scsi0,devno=fe.0.0001 +-drive file=/path/to/image,format=qcow2,if=none,id=drive-scsi0-0-0-0 +-device +scsi-hd,bus=scsi0.0,channel=0,scsi-id=0,lun=0,drive=drive-scsi0-0-0-0,id=scsi0-0-0-0,bootindex=1 +-device virtio-net-ccw + +It seems it needs the guest actually doing something with the nics; I +cannot reproduce the crash if I use the old advent calendar moon buggy +image and just add a virtio-net-ccw device. + +(I don't think it's a problem with my local build, as I see the problem +both on my laptop and on an LPAR.) +It looks to me we forget the check the existence of peer. + +Please try the attached patch to see if it works. +Thanks, that patch gets my guest up and running again. So, FWIW, + +Tested-by: Cornelia Huck <cohuck@redhat.com> + +Any idea why this did not hit with virtio-net-pci (or the autogenerated +virtio-net-ccw device)? +It can be hit with virtio-net-pci as well (just start without peer). +Hm, I had not been able to reproduce the crash with a 'naked' -device +virtio-net-pci. But checking seems to be the right idea anyway. +Sorry for being unclear, I meant for networking part, you just need +start without peer, and you need a real guest (any Linux) that is trying +to access the config space of virtio-net. +Thanks +For autogenerated virtio-net-cww, I think the reason is that it has +already had a peer set. +Ok, that might well be. + +On Mon, Jul 27, 2020 at 04:51:23PM +0800, Jason Wang wrote: +> +> +On 2020/7/27 ä¸å4:41, Cornelia Huck wrote: +> +> On Mon, 27 Jul 2020 15:38:12 +0800 +> +> Jason Wang <jasowang@redhat.com> wrote: +> +> +> +> > On 2020/7/27 ä¸å2:43, Cornelia Huck wrote: +> +> > > On Sat, 25 Jul 2020 08:40:07 +0800 +> +> > > Jason Wang <jasowang@redhat.com> wrote: +> +> > > > On 2020/7/24 ä¸å11:34, Cornelia Huck wrote: +> +> > > > > On Fri, 24 Jul 2020 11:17:57 -0400 +> +> > > > > "Michael S. Tsirkin"<mst@redhat.com> wrote: +> +> > > > > > On Fri, Jul 24, 2020 at 04:56:27PM +0200, Cornelia Huck wrote: +> +> > > > > > > On Fri, 24 Jul 2020 09:30:58 -0400 +> +> > > > > > > "Michael S. Tsirkin"<mst@redhat.com> wrote: +> +> > > > > > > > On Fri, Jul 24, 2020 at 03:27:18PM +0200, Cornelia Huck wrote: +> +> > > > > > > > > When I start qemu with a second virtio-net-ccw device (i.e. +> +> > > > > > > > > adding +> +> > > > > > > > > -device virtio-net-ccw in addition to the autogenerated +> +> > > > > > > > > device), I get +> +> > > > > > > > > a segfault. gdb points to +> +> > > > > > > > > +> +> > > > > > > > > #0 0x000055d6ab52681d in virtio_net_get_config +> +> > > > > > > > > (vdev=<optimized out>, +> +> > > > > > > > > config=0x55d6ad9e3f80 "RT") at +> +> > > > > > > > > /home/cohuck/git/qemu/hw/net/virtio-net.c:146 +> +> > > > > > > > > 146 if (nc->peer->info->type == +> +> > > > > > > > > NET_CLIENT_DRIVER_VHOST_VDPA) { +> +> > > > > > > > > +> +> > > > > > > > > (backtrace doesn't go further) +> +> > > > > > > The core was incomplete, but running under gdb directly shows +> +> > > > > > > that it +> +> > > > > > > is just a bog-standard config space access (first for that +> +> > > > > > > device). +> +> > > > > > > +> +> > > > > > > The cause of the crash is that nc->peer is not set... no idea +> +> > > > > > > how that +> +> > > > > > > can happen, not that familiar with that part of QEMU. (Should +> +> > > > > > > the code +> +> > > > > > > check, or is that really something that should not happen?) +> +> > > > > > > +> +> > > > > > > What I don't understand is why it is set correctly for the +> +> > > > > > > first, +> +> > > > > > > autogenerated virtio-net-ccw device, but not for the second +> +> > > > > > > one, and +> +> > > > > > > why virtio-net-pci doesn't show these problems. The only +> +> > > > > > > difference +> +> > > > > > > between -ccw and -pci that comes to my mind here is that config +> +> > > > > > > space +> +> > > > > > > accesses for ccw are done via an asynchronous operation, so +> +> > > > > > > timing +> +> > > > > > > might be different. +> +> > > > > > Hopefully Jason has an idea. Could you post a full command line +> +> > > > > > please? Do you need a working guest to trigger this? Does this +> +> > > > > > trigger +> +> > > > > > on an x86 host? +> +> > > > > Yes, it does trigger with tcg-on-x86 as well. I've been using +> +> > > > > +> +> > > > > s390x-softmmu/qemu-system-s390x -M s390-ccw-virtio,accel=tcg -cpu +> +> > > > > qemu,zpci=on +> +> > > > > -m 1024 -nographic -device virtio-scsi-ccw,id=scsi0,devno=fe.0.0001 +> +> > > > > -drive file=/path/to/image,format=qcow2,if=none,id=drive-scsi0-0-0-0 +> +> > > > > -device +> +> > > > > scsi-hd,bus=scsi0.0,channel=0,scsi-id=0,lun=0,drive=drive-scsi0-0-0-0,id=scsi0-0-0-0,bootindex=1 +> +> > > > > -device virtio-net-ccw +> +> > > > > +> +> > > > > It seems it needs the guest actually doing something with the nics; +> +> > > > > I +> +> > > > > cannot reproduce the crash if I use the old advent calendar moon +> +> > > > > buggy +> +> > > > > image and just add a virtio-net-ccw device. +> +> > > > > +> +> > > > > (I don't think it's a problem with my local build, as I see the +> +> > > > > problem +> +> > > > > both on my laptop and on an LPAR.) +> +> > > > It looks to me we forget the check the existence of peer. +> +> > > > +> +> > > > Please try the attached patch to see if it works. +> +> > > Thanks, that patch gets my guest up and running again. So, FWIW, +> +> > > +> +> > > Tested-by: Cornelia Huck <cohuck@redhat.com> +> +> > > +> +> > > Any idea why this did not hit with virtio-net-pci (or the autogenerated +> +> > > virtio-net-ccw device)? +> +> > +> +> > It can be hit with virtio-net-pci as well (just start without peer). +> +> Hm, I had not been able to reproduce the crash with a 'naked' -device +> +> virtio-net-pci. But checking seems to be the right idea anyway. +> +> +> +Sorry for being unclear, I meant for networking part, you just need start +> +without peer, and you need a real guest (any Linux) that is trying to access +> +the config space of virtio-net. +> +> +Thanks +A pxe guest will do it, but that doesn't support ccw, right? + +I'm still unclear why this triggers with ccw but not pci - +any idea? + +> +> +> +> +> > For autogenerated virtio-net-cww, I think the reason is that it has +> +> > already had a peer set. +> +> Ok, that might well be. +> +> +> +> + +On 2020/7/27 ä¸å7:43, Michael S. Tsirkin wrote: +On Mon, Jul 27, 2020 at 04:51:23PM +0800, Jason Wang wrote: +On 2020/7/27 ä¸å4:41, Cornelia Huck wrote: +On Mon, 27 Jul 2020 15:38:12 +0800 +Jason Wang<jasowang@redhat.com> wrote: +On 2020/7/27 ä¸å2:43, Cornelia Huck wrote: +On Sat, 25 Jul 2020 08:40:07 +0800 +Jason Wang<jasowang@redhat.com> wrote: +On 2020/7/24 ä¸å11:34, Cornelia Huck wrote: +On Fri, 24 Jul 2020 11:17:57 -0400 +"Michael S. Tsirkin"<mst@redhat.com> wrote: +On Fri, Jul 24, 2020 at 04:56:27PM +0200, Cornelia Huck wrote: +On Fri, 24 Jul 2020 09:30:58 -0400 +"Michael S. Tsirkin"<mst@redhat.com> wrote: +On Fri, Jul 24, 2020 at 03:27:18PM +0200, Cornelia Huck wrote: +When I start qemu with a second virtio-net-ccw device (i.e. adding +-device virtio-net-ccw in addition to the autogenerated device), I get +a segfault. gdb points to + +#0 0x000055d6ab52681d in virtio_net_get_config (vdev=<optimized out>, + config=0x55d6ad9e3f80 "RT") at +/home/cohuck/git/qemu/hw/net/virtio-net.c:146 +146 if (nc->peer->info->type == NET_CLIENT_DRIVER_VHOST_VDPA) { + +(backtrace doesn't go further) +The core was incomplete, but running under gdb directly shows that it +is just a bog-standard config space access (first for that device). + +The cause of the crash is that nc->peer is not set... no idea how that +can happen, not that familiar with that part of QEMU. (Should the code +check, or is that really something that should not happen?) + +What I don't understand is why it is set correctly for the first, +autogenerated virtio-net-ccw device, but not for the second one, and +why virtio-net-pci doesn't show these problems. The only difference +between -ccw and -pci that comes to my mind here is that config space +accesses for ccw are done via an asynchronous operation, so timing +might be different. +Hopefully Jason has an idea. Could you post a full command line +please? Do you need a working guest to trigger this? Does this trigger +on an x86 host? +Yes, it does trigger with tcg-on-x86 as well. I've been using + +s390x-softmmu/qemu-system-s390x -M s390-ccw-virtio,accel=tcg -cpu qemu,zpci=on +-m 1024 -nographic -device virtio-scsi-ccw,id=scsi0,devno=fe.0.0001 +-drive file=/path/to/image,format=qcow2,if=none,id=drive-scsi0-0-0-0 +-device +scsi-hd,bus=scsi0.0,channel=0,scsi-id=0,lun=0,drive=drive-scsi0-0-0-0,id=scsi0-0-0-0,bootindex=1 +-device virtio-net-ccw + +It seems it needs the guest actually doing something with the nics; I +cannot reproduce the crash if I use the old advent calendar moon buggy +image and just add a virtio-net-ccw device. + +(I don't think it's a problem with my local build, as I see the problem +both on my laptop and on an LPAR.) +It looks to me we forget the check the existence of peer. + +Please try the attached patch to see if it works. +Thanks, that patch gets my guest up and running again. So, FWIW, + +Tested-by: Cornelia Huck<cohuck@redhat.com> + +Any idea why this did not hit with virtio-net-pci (or the autogenerated +virtio-net-ccw device)? +It can be hit with virtio-net-pci as well (just start without peer). +Hm, I had not been able to reproduce the crash with a 'naked' -device +virtio-net-pci. But checking seems to be the right idea anyway. +Sorry for being unclear, I meant for networking part, you just need start +without peer, and you need a real guest (any Linux) that is trying to access +the config space of virtio-net. + +Thanks +A pxe guest will do it, but that doesn't support ccw, right? +Yes, it depends on the cli actually. +I'm still unclear why this triggers with ccw but not pci - +any idea? +I don't test pxe but I can reproduce this with pci (just start a linux +guest without a peer). +Thanks + +On Mon, Jul 27, 2020 at 08:44:09PM +0800, Jason Wang wrote: +> +> +On 2020/7/27 ä¸å7:43, Michael S. Tsirkin wrote: +> +> On Mon, Jul 27, 2020 at 04:51:23PM +0800, Jason Wang wrote: +> +> > On 2020/7/27 ä¸å4:41, Cornelia Huck wrote: +> +> > > On Mon, 27 Jul 2020 15:38:12 +0800 +> +> > > Jason Wang<jasowang@redhat.com> wrote: +> +> > > +> +> > > > On 2020/7/27 ä¸å2:43, Cornelia Huck wrote: +> +> > > > > On Sat, 25 Jul 2020 08:40:07 +0800 +> +> > > > > Jason Wang<jasowang@redhat.com> wrote: +> +> > > > > > On 2020/7/24 ä¸å11:34, Cornelia Huck wrote: +> +> > > > > > > On Fri, 24 Jul 2020 11:17:57 -0400 +> +> > > > > > > "Michael S. Tsirkin"<mst@redhat.com> wrote: +> +> > > > > > > > On Fri, Jul 24, 2020 at 04:56:27PM +0200, Cornelia Huck wrote: +> +> > > > > > > > > On Fri, 24 Jul 2020 09:30:58 -0400 +> +> > > > > > > > > "Michael S. Tsirkin"<mst@redhat.com> wrote: +> +> > > > > > > > > > On Fri, Jul 24, 2020 at 03:27:18PM +0200, Cornelia Huck +> +> > > > > > > > > > wrote: +> +> > > > > > > > > > > When I start qemu with a second virtio-net-ccw device +> +> > > > > > > > > > > (i.e. adding +> +> > > > > > > > > > > -device virtio-net-ccw in addition to the autogenerated +> +> > > > > > > > > > > device), I get +> +> > > > > > > > > > > a segfault. gdb points to +> +> > > > > > > > > > > +> +> > > > > > > > > > > #0 0x000055d6ab52681d in virtio_net_get_config +> +> > > > > > > > > > > (vdev=<optimized out>, +> +> > > > > > > > > > > config=0x55d6ad9e3f80 "RT") at +> +> > > > > > > > > > > /home/cohuck/git/qemu/hw/net/virtio-net.c:146 +> +> > > > > > > > > > > 146 if (nc->peer->info->type == +> +> > > > > > > > > > > NET_CLIENT_DRIVER_VHOST_VDPA) { +> +> > > > > > > > > > > +> +> > > > > > > > > > > (backtrace doesn't go further) +> +> > > > > > > > > The core was incomplete, but running under gdb directly +> +> > > > > > > > > shows that it +> +> > > > > > > > > is just a bog-standard config space access (first for that +> +> > > > > > > > > device). +> +> > > > > > > > > +> +> > > > > > > > > The cause of the crash is that nc->peer is not set... no +> +> > > > > > > > > idea how that +> +> > > > > > > > > can happen, not that familiar with that part of QEMU. +> +> > > > > > > > > (Should the code +> +> > > > > > > > > check, or is that really something that should not happen?) +> +> > > > > > > > > +> +> > > > > > > > > What I don't understand is why it is set correctly for the +> +> > > > > > > > > first, +> +> > > > > > > > > autogenerated virtio-net-ccw device, but not for the second +> +> > > > > > > > > one, and +> +> > > > > > > > > why virtio-net-pci doesn't show these problems. The only +> +> > > > > > > > > difference +> +> > > > > > > > > between -ccw and -pci that comes to my mind here is that +> +> > > > > > > > > config space +> +> > > > > > > > > accesses for ccw are done via an asynchronous operation, so +> +> > > > > > > > > timing +> +> > > > > > > > > might be different. +> +> > > > > > > > Hopefully Jason has an idea. Could you post a full command +> +> > > > > > > > line +> +> > > > > > > > please? Do you need a working guest to trigger this? Does +> +> > > > > > > > this trigger +> +> > > > > > > > on an x86 host? +> +> > > > > > > Yes, it does trigger with tcg-on-x86 as well. I've been using +> +> > > > > > > +> +> > > > > > > s390x-softmmu/qemu-system-s390x -M s390-ccw-virtio,accel=tcg +> +> > > > > > > -cpu qemu,zpci=on +> +> > > > > > > -m 1024 -nographic -device +> +> > > > > > > virtio-scsi-ccw,id=scsi0,devno=fe.0.0001 +> +> > > > > > > -drive +> +> > > > > > > file=/path/to/image,format=qcow2,if=none,id=drive-scsi0-0-0-0 +> +> > > > > > > -device +> +> > > > > > > scsi-hd,bus=scsi0.0,channel=0,scsi-id=0,lun=0,drive=drive-scsi0-0-0-0,id=scsi0-0-0-0,bootindex=1 +> +> > > > > > > -device virtio-net-ccw +> +> > > > > > > +> +> > > > > > > It seems it needs the guest actually doing something with the +> +> > > > > > > nics; I +> +> > > > > > > cannot reproduce the crash if I use the old advent calendar +> +> > > > > > > moon buggy +> +> > > > > > > image and just add a virtio-net-ccw device. +> +> > > > > > > +> +> > > > > > > (I don't think it's a problem with my local build, as I see the +> +> > > > > > > problem +> +> > > > > > > both on my laptop and on an LPAR.) +> +> > > > > > It looks to me we forget the check the existence of peer. +> +> > > > > > +> +> > > > > > Please try the attached patch to see if it works. +> +> > > > > Thanks, that patch gets my guest up and running again. So, FWIW, +> +> > > > > +> +> > > > > Tested-by: Cornelia Huck<cohuck@redhat.com> +> +> > > > > +> +> > > > > Any idea why this did not hit with virtio-net-pci (or the +> +> > > > > autogenerated +> +> > > > > virtio-net-ccw device)? +> +> > > > It can be hit with virtio-net-pci as well (just start without peer). +> +> > > Hm, I had not been able to reproduce the crash with a 'naked' -device +> +> > > virtio-net-pci. But checking seems to be the right idea anyway. +> +> > Sorry for being unclear, I meant for networking part, you just need start +> +> > without peer, and you need a real guest (any Linux) that is trying to +> +> > access +> +> > the config space of virtio-net. +> +> > +> +> > Thanks +> +> A pxe guest will do it, but that doesn't support ccw, right? +> +> +> +Yes, it depends on the cli actually. +> +> +> +> +> +> I'm still unclear why this triggers with ccw but not pci - +> +> any idea? +> +> +> +I don't test pxe but I can reproduce this with pci (just start a linux guest +> +without a peer). +> +> +Thanks +> +Might be a good addition to a unit test. Not sure what would the +test do exactly: just make sure guest runs? Looks like a lot of work +for an empty test ... maybe we can poke at the guest config with +qtest commands at least. + +-- +MST + +On 2020/7/27 ä¸å9:16, Michael S. Tsirkin wrote: +On Mon, Jul 27, 2020 at 08:44:09PM +0800, Jason Wang wrote: +On 2020/7/27 ä¸å7:43, Michael S. Tsirkin wrote: +On Mon, Jul 27, 2020 at 04:51:23PM +0800, Jason Wang wrote: +On 2020/7/27 ä¸å4:41, Cornelia Huck wrote: +On Mon, 27 Jul 2020 15:38:12 +0800 +Jason Wang<jasowang@redhat.com> wrote: +On 2020/7/27 ä¸å2:43, Cornelia Huck wrote: +On Sat, 25 Jul 2020 08:40:07 +0800 +Jason Wang<jasowang@redhat.com> wrote: +On 2020/7/24 ä¸å11:34, Cornelia Huck wrote: +On Fri, 24 Jul 2020 11:17:57 -0400 +"Michael S. Tsirkin"<mst@redhat.com> wrote: +On Fri, Jul 24, 2020 at 04:56:27PM +0200, Cornelia Huck wrote: +On Fri, 24 Jul 2020 09:30:58 -0400 +"Michael S. Tsirkin"<mst@redhat.com> wrote: +On Fri, Jul 24, 2020 at 03:27:18PM +0200, Cornelia Huck wrote: +When I start qemu with a second virtio-net-ccw device (i.e. adding +-device virtio-net-ccw in addition to the autogenerated device), I get +a segfault. gdb points to + +#0 0x000055d6ab52681d in virtio_net_get_config (vdev=<optimized out>, + config=0x55d6ad9e3f80 "RT") at +/home/cohuck/git/qemu/hw/net/virtio-net.c:146 +146 if (nc->peer->info->type == NET_CLIENT_DRIVER_VHOST_VDPA) { + +(backtrace doesn't go further) +The core was incomplete, but running under gdb directly shows that it +is just a bog-standard config space access (first for that device). + +The cause of the crash is that nc->peer is not set... no idea how that +can happen, not that familiar with that part of QEMU. (Should the code +check, or is that really something that should not happen?) + +What I don't understand is why it is set correctly for the first, +autogenerated virtio-net-ccw device, but not for the second one, and +why virtio-net-pci doesn't show these problems. The only difference +between -ccw and -pci that comes to my mind here is that config space +accesses for ccw are done via an asynchronous operation, so timing +might be different. +Hopefully Jason has an idea. Could you post a full command line +please? Do you need a working guest to trigger this? Does this trigger +on an x86 host? +Yes, it does trigger with tcg-on-x86 as well. I've been using + +s390x-softmmu/qemu-system-s390x -M s390-ccw-virtio,accel=tcg -cpu qemu,zpci=on +-m 1024 -nographic -device virtio-scsi-ccw,id=scsi0,devno=fe.0.0001 +-drive file=/path/to/image,format=qcow2,if=none,id=drive-scsi0-0-0-0 +-device +scsi-hd,bus=scsi0.0,channel=0,scsi-id=0,lun=0,drive=drive-scsi0-0-0-0,id=scsi0-0-0-0,bootindex=1 +-device virtio-net-ccw + +It seems it needs the guest actually doing something with the nics; I +cannot reproduce the crash if I use the old advent calendar moon buggy +image and just add a virtio-net-ccw device. + +(I don't think it's a problem with my local build, as I see the problem +both on my laptop and on an LPAR.) +It looks to me we forget the check the existence of peer. + +Please try the attached patch to see if it works. +Thanks, that patch gets my guest up and running again. So, FWIW, + +Tested-by: Cornelia Huck<cohuck@redhat.com> + +Any idea why this did not hit with virtio-net-pci (or the autogenerated +virtio-net-ccw device)? +It can be hit with virtio-net-pci as well (just start without peer). +Hm, I had not been able to reproduce the crash with a 'naked' -device +virtio-net-pci. But checking seems to be the right idea anyway. +Sorry for being unclear, I meant for networking part, you just need start +without peer, and you need a real guest (any Linux) that is trying to access +the config space of virtio-net. + +Thanks +A pxe guest will do it, but that doesn't support ccw, right? +Yes, it depends on the cli actually. +I'm still unclear why this triggers with ccw but not pci - +any idea? +I don't test pxe but I can reproduce this with pci (just start a linux guest +without a peer). + +Thanks +Might be a good addition to a unit test. Not sure what would the +test do exactly: just make sure guest runs? Looks like a lot of work +for an empty test ... maybe we can poke at the guest config with +qtest commands at least. +That should work or we can simply extend the exist virtio-net qtest to +do that. +Thanks + |