* [Qemu-devel] Crash with pcie-pci-bridge on qemu-system-s390x
@ 2017-11-02 14:19 Thomas Huth
2017-11-02 14:42 ` Marcel Apfelbaum
0 siblings, 1 reply; 4+ messages in thread
From: Thomas Huth @ 2017-11-02 14:19 UTC (permalink / raw)
To: QEMU Developers, qemu-s390x; +Cc: Aleksandr Bezzubikov, Marcel Apfelbaum
Hi,
seems like there's a new way to crash QEMU with the pcie-pci-bridge
device (using QEMU master branch of today):
$ s390x-softmmu/qemu-system-s390x -nographic -S
QEMU 2.10.50 monitor - type 'help' for more information
(qemu) device_add pcie-pci-bridge,id=x
Segmentation fault (core dumped)
Does anybody have a clue what might be wrong here?
Backtrace looks like this:
#0 0x000055555577064b in pci_default_write_config (d=d@entry=0x0,
addr=addr@entry=26, val_in=1, l=l@entry=1) at
/home/thuth/devel/qemu/hw/pci/pci.c:1367
#1 0x00005555556c885f in s390_pcihost_hot_plug (hotplug_dev=<optimized
out>, dev=0x55555639b160, errp=0x7fffffffc5a0) at
/home/thuth/devel/qemu/hw/s390x/s390-pci-bus.c:684
#2 0x000055555575afeb in device_set_realized (obj=<optimized out>,
value=<optimized out>, errp=0x7fffffffc6d8) at
/home/thuth/devel/qemu/hw/core/qdev.c:936
#3 0x00005555557ee48e in property_set_bool (obj=0x55555639b160,
v=<optimized out>, name=<optimized out>, opaque=0x555556399fe0,
errp=0x7fffffffc6d8)
at /home/thuth/devel/qemu/qom/object.c:1906
#4 0x00005555557f25ff in object_property_set_qobject
(obj=obj@entry=0x55555639b160, value=value@entry=0x55555639d170,
name=name@entry=0x5555559a4157 "realized",
errp=errp@entry=0x7fffffffc6d8) at
/home/thuth/devel/qemu/qom/qom-qobject.c:27
#5 0x00005555557f0270 in object_property_set_bool (obj=0x55555639b160,
value=<optimized out>, name=0x5555559a4157 "realized", errp=0x7fffffffc6d8)
at /home/thuth/devel/qemu/qom/object.c:1171
#6 0x000055555570b549 in qdev_device_add
(opts=opts@entry=0x55555640cb50, errp=errp@entry=0x7fffffffc7b0) at
/home/thuth/devel/qemu/qdev-monitor.c:632
...
Thomas
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [Qemu-devel] Crash with pcie-pci-bridge on qemu-system-s390x
2017-11-02 14:19 [Qemu-devel] Crash with pcie-pci-bridge on qemu-system-s390x Thomas Huth
@ 2017-11-02 14:42 ` Marcel Apfelbaum
2017-11-02 14:59 ` Aleksandr Bezzubikov
0 siblings, 1 reply; 4+ messages in thread
From: Marcel Apfelbaum @ 2017-11-02 14:42 UTC (permalink / raw)
To: Thomas Huth, QEMU Developers, qemu-s390x; +Cc: Aleksandr Bezzubikov
On 02/11/2017 16:19, Thomas Huth wrote:
> Hi,
>
Hi Thomas,
> seems like there's a new way to crash QEMU with the pcie-pci-bridge
> device (using QEMU master branch of today):
> > $ s390x-softmmu/qemu-system-s390x -nographic -S
> QEMU 2.10.50 monitor - type 'help' for more information
> (qemu) device_add pcie-pci-bridge,id=x
> Segmentation fault (core dumped)
>
Thanks for noticing it.
> Does anybody have a clue what might be wrong here?
>
It was tested with X86 and I think aarch64.
I am not sure how it would work with or if we
really need it for s390.
We need the device to start a PCI hierarchy by plugging
it to PCIe Root Port. If I understand correctly s390
does not use PCIe Root Ports and may not need it.
If the assumption is correct I suppose we should only
be compiled into the above archs.
If you agree, I can post a patch for this.
Thanks,
Marcel
> Backtrace looks like this:
>
> #0 0x000055555577064b in pci_default_write_config (d=d@entry=0x0,
> addr=addr@entry=26, val_in=1, l=l@entry=1) at
> /home/thuth/devel/qemu/hw/pci/pci.c:1367
> #1 0x00005555556c885f in s390_pcihost_hot_plug (hotplug_dev=<optimized
> out>, dev=0x55555639b160, errp=0x7fffffffc5a0) at
> /home/thuth/devel/qemu/hw/s390x/s390-pci-bus.c:684
> #2 0x000055555575afeb in device_set_realized (obj=<optimized out>,
> value=<optimized out>, errp=0x7fffffffc6d8) at
> /home/thuth/devel/qemu/hw/core/qdev.c:936
> #3 0x00005555557ee48e in property_set_bool (obj=0x55555639b160,
> v=<optimized out>, name=<optimized out>, opaque=0x555556399fe0,
> errp=0x7fffffffc6d8)
> at /home/thuth/devel/qemu/qom/object.c:1906
> #4 0x00005555557f25ff in object_property_set_qobject
> (obj=obj@entry=0x55555639b160, value=value@entry=0x55555639d170,
> name=name@entry=0x5555559a4157 "realized",
> errp=errp@entry=0x7fffffffc6d8) at
> /home/thuth/devel/qemu/qom/qom-qobject.c:27
> #5 0x00005555557f0270 in object_property_set_bool (obj=0x55555639b160,
> value=<optimized out>, name=0x5555559a4157 "realized", errp=0x7fffffffc6d8)
> at /home/thuth/devel/qemu/qom/object.c:1171
> #6 0x000055555570b549 in qdev_device_add
> (opts=opts@entry=0x55555640cb50, errp=errp@entry=0x7fffffffc7b0) at
> /home/thuth/devel/qemu/qdev-monitor.c:632
> ...
>
> Thomas
>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [Qemu-devel] Crash with pcie-pci-bridge on qemu-system-s390x
2017-11-02 14:42 ` Marcel Apfelbaum
@ 2017-11-02 14:59 ` Aleksandr Bezzubikov
2017-11-07 10:34 ` Cornelia Huck
0 siblings, 1 reply; 4+ messages in thread
From: Aleksandr Bezzubikov @ 2017-11-02 14:59 UTC (permalink / raw)
To: Marcel Apfelbaum; +Cc: Thomas Huth, QEMU Developers, qemu-s390x
2017-11-02 17:42 GMT+03:00 Marcel Apfelbaum <marcel@redhat.com>:
> On 02/11/2017 16:19, Thomas Huth wrote:
>>
>> Hi,
>>
>
> Hi Thomas,
>
Hi Thomas, Marcel,
>> seems like there's a new way to crash QEMU with the pcie-pci-bridge
>> device (using QEMU master branch of today):
>> > $ s390x-softmmu/qemu-system-s390x -nographic -S
>> QEMU 2.10.50 monitor - type 'help' for more information
>> (qemu) device_add pcie-pci-bridge,id=x
>> Segmentation fault (core dumped)
>>
>
> Thanks for noticing it.
>
>> Does anybody have a clue what might be wrong here?
>>
>
> It was tested with X86 and I think aarch64.
> I am not sure how it would work with or if we
> really need it for s390.
>
> We need the device to start a PCI hierarchy by plugging
> it to PCIe Root Port. If I understand correctly s390
> does not use PCIe Root Ports and may not need it.
>
Personally I can see 2 issues here:
1) [Marcel's already mentioned it] It seems that s390x machines have
only pure PCI hosts,
that's why it's a bit weird to put pcie-pci-bridge into the host
2) The actual segfault cause is bridge parent bus not having a parent
device (somehow).
Maybe it's a consequence of point 1)
> If the assumption is correct I suppose we should only
> be compiled into the above archs.
> If you agree, I can post a patch for this.
>
> Thanks,
> Marcel
>
>
>> Backtrace looks like this:
>>
>> #0 0x000055555577064b in pci_default_write_config (d=d@entry=0x0,
>> addr=addr@entry=26, val_in=1, l=l@entry=1) at
>> /home/thuth/devel/qemu/hw/pci/pci.c:1367
>> #1 0x00005555556c885f in s390_pcihost_hot_plug (hotplug_dev=<optimized
>> out>, dev=0x55555639b160, errp=0x7fffffffc5a0) at
>> /home/thuth/devel/qemu/hw/s390x/s390-pci-bus.c:684
>> #2 0x000055555575afeb in device_set_realized (obj=<optimized out>,
>> value=<optimized out>, errp=0x7fffffffc6d8) at
>> /home/thuth/devel/qemu/hw/core/qdev.c:936
>> #3 0x00005555557ee48e in property_set_bool (obj=0x55555639b160,
>> v=<optimized out>, name=<optimized out>, opaque=0x555556399fe0,
>> errp=0x7fffffffc6d8)
>> at /home/thuth/devel/qemu/qom/object.c:1906
>> #4 0x00005555557f25ff in object_property_set_qobject
>> (obj=obj@entry=0x55555639b160, value=value@entry=0x55555639d170,
>> name=name@entry=0x5555559a4157 "realized",
>> errp=errp@entry=0x7fffffffc6d8) at
>> /home/thuth/devel/qemu/qom/qom-qobject.c:27
>> #5 0x00005555557f0270 in object_property_set_bool (obj=0x55555639b160,
>> value=<optimized out>, name=0x5555559a4157 "realized",
>> errp=0x7fffffffc6d8)
>> at /home/thuth/devel/qemu/qom/object.c:1171
>> #6 0x000055555570b549 in qdev_device_add
>> (opts=opts@entry=0x55555640cb50, errp=errp@entry=0x7fffffffc7b0) at
>> /home/thuth/devel/qemu/qdev-monitor.c:632
>> ...
>>
>> Thomas
>>
>
Thanks,
Aleksandr Bezzubikov
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [Qemu-devel] Crash with pcie-pci-bridge on qemu-system-s390x
2017-11-02 14:59 ` Aleksandr Bezzubikov
@ 2017-11-07 10:34 ` Cornelia Huck
0 siblings, 0 replies; 4+ messages in thread
From: Cornelia Huck @ 2017-11-07 10:34 UTC (permalink / raw)
To: Aleksandr Bezzubikov
Cc: Marcel Apfelbaum, qemu-s390x, Thomas Huth, QEMU Developers
On Thu, 2 Nov 2017 17:59:58 +0300
Aleksandr Bezzubikov <zuban32s@gmail.com> wrote:
> 2017-11-02 17:42 GMT+03:00 Marcel Apfelbaum <marcel@redhat.com>:
> > On 02/11/2017 16:19, Thomas Huth wrote:
> >>
> >> Hi,
> >>
> >
> > Hi Thomas,
> >
>
> Hi Thomas, Marcel,
>
> >> seems like there's a new way to crash QEMU with the pcie-pci-bridge
> >> device (using QEMU master branch of today):
> >> > $ s390x-softmmu/qemu-system-s390x -nographic -S
> >> QEMU 2.10.50 monitor - type 'help' for more information
> >> (qemu) device_add pcie-pci-bridge,id=x
> >> Segmentation fault (core dumped)
> >>
> >
> > Thanks for noticing it.
> >
> >> Does anybody have a clue what might be wrong here?
> >>
> >
> > It was tested with X86 and I think aarch64.
> > I am not sure how it would work with or if we
> > really need it for s390.
> >
> > We need the device to start a PCI hierarchy by plugging
> > it to PCIe Root Port. If I understand correctly s390
> > does not use PCIe Root Ports and may not need it.
> >
>
> Personally I can see 2 issues here:
> 1) [Marcel's already mentioned it] It seems that s390x machines have
> only pure PCI hosts,
> that's why it's a bit weird to put pcie-pci-bridge into the host
> 2) The actual segfault cause is bridge parent bus not having a parent
> device (somehow).
> Maybe it's a consequence of point 1)
Yes. PCI on s390x is weird; we basically have no topology and just make
one up (of which the guest sees nothing at all).
>
> > If the assumption is correct I suppose we should only
> > be compiled into the above archs.
> > If you agree, I can post a patch for this.
I think disabling this for s390x makes sense.
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2017-11-07 10:35 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2017-11-02 14:19 [Qemu-devel] Crash with pcie-pci-bridge on qemu-system-s390x Thomas Huth
2017-11-02 14:42 ` Marcel Apfelbaum
2017-11-02 14:59 ` Aleksandr Bezzubikov
2017-11-07 10:34 ` Cornelia Huck
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).