Re: Linux 3.4 released

From: Jörg-Volker Peetz
Date: Wed May 23 2012 - 15:56:56 EST


Tejun Heo wrote, on 05/23/12 20:24:
> Hello, Jörg-Volker.
>
> Please always use reply-to-all.
>
> On Tue, May 22, 2012 at 09:50:10PM +0200, Jörg-Volker Peetz wrote:
>> no, changing to printk(KERN_CRIT "XXX: ...", ...) in kernel/workqueue.c didn't
>> print anything I could read. Would it appear before the "panic screen"? But I'm
>> not able to scroll back.
>> The Panic screen starts with
>
> It should appear right above BUG:. Can you please try the following
> instead?
>
> Thanks.
>
> diff --git a/kernel/workqueue.c b/kernel/workqueue.c
> index 5abf42f..57c33ef 100644
> --- a/kernel/workqueue.c
> +++ b/kernel/workqueue.c
> @@ -1096,10 +1096,18 @@ queue_work_on(int cpu, struct workqueue_struct *wq, struct work_struct *work)
> }
> EXPORT_SYMBOL_GPL(queue_work_on);
>
> +#include <linux/uaccess.h>
> static void delayed_work_timer_fn(unsigned long __data)
> {
> struct delayed_work *dwork = (struct delayed_work *)__data;
> struct cpu_workqueue_struct *cwq = get_work_cwq(&dwork->work);
> + unsigned long v;
> +
> + if (probe_kernel_read(&v, &cwq->wq, sizeof(v))) {
> + printk(KERN_CRIT "XXX delayed_work_timer_fn: cwq %p, fn=%pf\n",
> + cwq, dwork->work.func);
> + return;
> + }
>
> __queue_work(smp_processor_id(), cwq->wq, &dwork->work);
> }

Hello Tejun,

thank you for bearing with me. I applied this patch. When starting "guvcvideo"
now, the computer seems to work normally, i.e. this program shows the view from
the built-in USB web-cam on the screen. In the kernel log file it says:

May 23 21:32:33 hostname kernel: XXX delayed_work_timer_fn: cwq
(null), fn=hdmi_repoll_eld

(without line-break).

By the way, don't know if this is related, I have a phenomenon with a spurious
interrupt with every linux version I've used before on this notebook. Half a
minute after starting the system the computer produces approx. 220 lines like

... kernel: hda-intel: spurious response 0x0:0x0, last cmd=0x170503

Now with 3.4.0, I see an additional message right before (the minute before) the
"XXX ..." line:

...kernel: hda_intel: azx_get_response timeout, switching to single_cmd mode:
last cmd=0x003f0900

--
Best regards,
Jörg-Volker.


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