This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
Home Products Support Community News


Re: [Xen-devel] Re: [patch] xenfb: fix xenfb suspend/resume race

To: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
Subject: Re: [Xen-devel] Re: [patch] xenfb: fix xenfb suspend/resume race
From: Joe Jin <joe.jin@xxxxxxxxxx>
Date: Tue, 04 Jan 2011 08:34:00 +0800
Cc: jeremy@xxxxxxxx, xen-devel@xxxxxxxxxxxxxxxxxxx, ian.campbell@xxxxxxxxxx, gurudas.pai@xxxxxxxxxx, guru.anbalagane@xxxxxxxxxx, greg.marsden@xxxxxxxxxx, linux-kernel@xxxxxxxxxxxxxxx, linux-fbdev@xxxxxxxxxxxxxxx, Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Delivery-date: Mon, 03 Jan 2011 16:35:15 -0800
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
In-reply-to: <20110103163418.GA14102@xxxxxxxxxxxx>
List-help: <mailto:xen-devel-request@lists.xensource.com?subject=help>
List-id: Xen developer discussion <xen-devel.lists.xensource.com>
List-post: <mailto:xen-devel@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
References: <20101230125616.GA31537@xxxxxxxxxxxxxxxxxxxxxxx> <20101230164051.GC24313@xxxxxxxxxxxx> <4D1D2A2D.80206@xxxxxxxxxx> <20110103163418.GA14102@xxxxxxxxxxxx>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
User-agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv: Gecko/20101209 Fedora/3.1.7-0.35.b3pre.fc14 Lightning/1.0b3pre OracleBeehiveExtension/ ObetStats/CATLAF_1292475699435-498544290 Thunderbird/3.1.7
On 01/04/11 00:34, Konrad Rzeszutek Wilk wrote:
>>> I am unclear from your description whether the patch fixes
>>> the problem (I would presume so). Or does it take a long time
>>> to hit this race?
>> Yes, more than 100 migrations. we hit this issue around 3 times.
> OK, so you are still trying to find the culprit.
> Did you look at this patch from Ian:
> https://patchwork.kernel.org/patch/403192/

We have reproduced the issue with the patch.

> ?
>> I dumped vmcore when guest crashed, from vmcore everything
>> looked good, fb_info, xenfb_info and so on.
> And the event channels are correct?
> .. snip..
>> diff --git a/drivers/xen/events.c b/drivers/xen/events.c
>> index ac7b42f..4cfb5e2 100644
>> --- a/drivers/xen/events.c
>> +++ b/drivers/xen/events.c
>> @@ -175,6 +175,8 @@ static struct irq_info *info_for_irq(unsigned irq)
>>  static unsigned int evtchn_from_irq(unsigned irq)
>>  {
>> +    if (unlikely(irq < 0 || irq >= nr_irqs))
>> +            return 0;
> You could insert a WARN_ON here to see see if you get this during your
> migration process.
> Or use xen_raw_printk in case the guest is hung for good.

Thanks for your advice, will try it.

Xen-devel mailing list