Re: [Xen-devel] Xen-unstable: Xen panic when shutting down HVM guest with PCI passthrough: RIP: e008:[<ffff82d0801099b1>] evtchn_move_pirqs+0x90/0xbf

[Sander Eikelenboom <linux@xxxxxxxxxxxxxx>]

Friday, June 6, 2014, 6:43:28 AM, you wrote:

> On 06/05/2014 06:22 PM, Andrew Cooper wrote:
>> On 05/06/14 17:03, Sander Eikelenboom wrote:
>>> Thursday, June 5, 2014, 5:03:24 PM, you wrote:
>>>
>>>> On 05/06/14 15:54, Sander Eikelenboom       wrote:
>>>>
>>>> Hi,
>>>> When shutting down a HVM guest with PCI passthrough Xen panics with the 
>>>> panic
>>>> below (complete xl-dmesg attached).
>>>> # addr2line -e xen-syms ffff82d0801099b1
>>>> /usr/src/new/xen-unstable/xen/common/event_channel.c:1326
>>>> which is:
>>>>          pirq_set_affinity(d, chn->u.pirq.irq, mask);
>>>>
>>>>
>>>>       This is presumably an ordering issue on destroy.
>>>>
>>>>       Does reverting bac6334b5 fix the problem?
>>>>
>>>>       ~Andrew
>>> Hi Andrew,
>>>
>>> That seems to have been a good hunch, after reverting that commit i have 
>>> been
>>> able to repeatedly create and shutdown the guest with passthrough, without 
>>> a crash.
>>>
>>> --
>>> Sander
>>>
>>
>> CC'ing George and Juergen as the authors of the identified patch
>>
>> c/s bac6334b5 "move domain to cpupool0 before destroying it" appears to
>> cause the crash identified the root of this thread.
>>
>> It appears to now move event channels after having torn parts of the
>> event channel infrastructure.

> Hmm, does the following patch fix it?


> Juergen

> diff --git a/xen/common/schedule.c b/xen/common/schedule.c
> index c174c41..3ea9fc8 100644
> --- a/xen/common/schedule.c
> +++ b/xen/common/schedule.c
> @@ -297,7 +297,8 @@ int sched_move_domain(struct domain *d, struct 
> cpupool *c)
>           spin_unlock_irq(lock);

>           v->sched_priv = vcpu_priv[v->vcpu_id];
> -        evtchn_move_pirqs(v);
+        if ( !d->>is_dying )
> +            evtchn_move_pirqs(v);

>           new_p = cpumask_cycle(new_p, c->cpu_valid);

Hi Jürgen,

Tried that one, it prevents the host panic, but immediately after i do get a:

[  658.222311] irq 16: nobody cared (try booting with the "irqpoll" option)
[  658.229069] CPU: 0 PID: 17104 Comm: smtp Not tainted 
3.15.0-rc8-20140602-net-xendev-bt-mq+ #1
[  658.235996] Hardware name: MSI MS-7640/890FXA-GD70 (MS-7640)  , BIOS V1.8B1 
09/13/2010
[  658.243234]  ffff880054b00718 ffff88005f603d98 ffffffff81b93243 
ffff88002e4e9330
[  658.250342]  ffff880054b00690 ffff88005f603dc8 ffffffff8112306d 
ffff88005f603dc8
[  658.257411]  ffff880054b00690 0000000000000010 0000000000000000 
ffff88005f603e18
[  658.264362] Call Trace:
[  658.271128]  <IRQ>  [<ffffffff81b93243>] dump_stack+0x46/0x58
[  658.278096]  [<ffffffff8112306d>] __report_bad_irq+0x3d/0xe0
[  658.285175]  [<ffffffff8112355f>] note_interrupt+0x1bf/0x210
[  658.292210]  [<ffffffff81120ca5>] handle_irq_event_percpu+0xb5/0x1e0
[  658.299135]  [<ffffffff81120e18>] handle_irq_event+0x48/0x70
[  658.306032]  [<ffffffff8112411f>] ? handle_fasteoi_irq+0x2f/0x150
[  658.312935]  [<ffffffff8112417c>] handle_fasteoi_irq+0x8c/0x150
[  658.319847]  [<ffffffff811204f2>] generic_handle_irq+0x22/0x40
[  658.326627]  [<ffffffff8157dfb7>] evtchn_fifo_handle_events+0x137/0x140
[  658.333370]  [<ffffffff8157aef0>] __xen_evtchn_do_upcall+0x50/0xa0
[  658.340061]  [<ffffffff8157cc37>] xen_evtchn_do_upcall+0x37/0x50
[  658.346575]  [<ffffffff81b9ff5e>] xen_do_hypervisor_callback+0x1e/0x30
[  658.353214]  <EOI>
[  658.353264] handlers:
[  658.366234] [<ffffffff819a2440>] azx_interrupt
[  658.372806] Disabling IRQ #16

Which could be related ?

--
Sander



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