[Qemu-devel] sending SEGV to qemu crashes host kernel in Fedora 19

[Qemu-devel] sending SEGV to qemu crashes host kernel in Fedora 19

[Dave Airlie]

Hi,

F19
kernel-3.9.8-300.fc19.x86_64
qemu-kvm-1.4.2-4.fc19.x86_64

If I start a complete F19 install in the guest and send the qemu
process a SEGV signal, the host kernel starts giving me random kmalloc
errors soon after, if I send a normal kill signal things seem fine.

CPU is Intel(R) Core(TM) i7-3770 CPU @ 3.40GHz, on a HP 220z workstation.

I initially blamed bad RAM but this reproduces everytime, and I
swapped DIMMs around

I haven't tested with upstream kernel/qemu yet, but I wondered if
anyone else has seen this.

I noticed this because some work I was doing was segfaulting my qemu
and then my machine would die a few mins later.

Dave.

Re: [Qemu-devel] sending SEGV to qemu crashes host kernel in Fedora 19

[Dave Airlie]

On Tue, Jul 9, 2013 at 10:35 AM, Dave Airlie <airlied@gmail.com> wrote:
> Hi,
>
> F19
> kernel-3.9.8-300.fc19.x86_64
> qemu-kvm-1.4.2-4.fc19.x86_64
>
> If I start a complete F19 install in the guest and send the qemu
> process a SEGV signal, the host kernel starts giving me random kmalloc
> errors soon after, if I send a normal kill signal things seem fine.
>
> CPU is Intel(R) Core(TM) i7-3770 CPU @ 3.40GHz, on a HP 220z workstation.
>
> I initially blamed bad RAM but this reproduces everytime, and I
> swapped DIMMs around
>
> I haven't tested with upstream kernel/qemu yet, but I wondered if
> anyone else has seen this.
>
> I noticed this because some work I was doing was segfaulting my qemu
> and then my machine would die a few mins later.

Of course now I read my fedora kernel emails and notice vhost_net does
bad things,

disabling vhost_net seems to make it work fine, hopefully the next
Fedora kernel will bring the magic fixes.

Dave.

Re: [Qemu-devel] sending SEGV to qemu crashes host kernel in Fedora 19

[Josh Boyer]

On Mon, Jul 8, 2013 at 9:11 PM, Dave Airlie <airlied@gmail.com> wrote:
> On Tue, Jul 9, 2013 at 10:35 AM, Dave Airlie <airlied@gmail.com> wrote:
>> Hi,
>>
>> F19
>> kernel-3.9.8-300.fc19.x86_64
>> qemu-kvm-1.4.2-4.fc19.x86_64
>>
>> If I start a complete F19 install in the guest and send the qemu
>> process a SEGV signal, the host kernel starts giving me random kmalloc
>> errors soon after, if I send a normal kill signal things seem fine.
>>
>> CPU is Intel(R) Core(TM) i7-3770 CPU @ 3.40GHz, on a HP 220z workstation.
>>
>> I initially blamed bad RAM but this reproduces everytime, and I
>> swapped DIMMs around
>>
>> I haven't tested with upstream kernel/qemu yet, but I wondered if
>> anyone else has seen this.
>>
>> I noticed this because some work I was doing was segfaulting my qemu
>> and then my machine would die a few mins later.
>
> Of course now I read my fedora kernel emails and notice vhost_net does
> bad things,
>
> disabling vhost_net seems to make it work fine, hopefully the next
> Fedora kernel will bring the magic fixes.

We hope so too.  3.9.9-302.fc19 in koji should contain the fixes we
know about.  There's still another bug open that's tracking issues
with Windows guest VMs and vhost-net.

josh

Re: [Qemu-devel] sending SEGV to qemu crashes host kernel in Fedora 19

[Cole Robinson]

On 07/08/2013 09:11 PM, Dave Airlie wrote:
> On Tue, Jul 9, 2013 at 10:35 AM, Dave Airlie <airlied@gmail.com> wrote:
>> Hi,
>>
>> F19
>> kernel-3.9.8-300.fc19.x86_64
>> qemu-kvm-1.4.2-4.fc19.x86_64
>>
>> If I start a complete F19 install in the guest and send the qemu
>> process a SEGV signal, the host kernel starts giving me random kmalloc
>> errors soon after, if I send a normal kill signal things seem fine.
>>
>> CPU is Intel(R) Core(TM) i7-3770 CPU @ 3.40GHz, on a HP 220z workstation.
>>
>> I initially blamed bad RAM but this reproduces everytime, and I
>> swapped DIMMs around
>>
>> I haven't tested with upstream kernel/qemu yet, but I wondered if
>> anyone else has seen this.
>>
>> I noticed this because some work I was doing was segfaulting my qemu
>> and then my machine would die a few mins later.
> 
> Of course now I read my fedora kernel emails and notice vhost_net does
> bad things,
> 
> disabling vhost_net seems to make it work fine, hopefully the next
> Fedora kernel will bring the magic fixes.
> 

That issue and another nasty crasher are being tracked here:

https://bugzilla.redhat.com/show_bug.cgi?id=980254

- Cole