System freeze - kernel errors

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dkked
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System freeze - kernel errors

Post by dkked »

Hi,

I've been unlucky to keep my C1 stable and operational. Each day it freezes, requiring a hard reboot to work again.
I've upgraded to the latest c1 image and all packages are up to date, kernel 3.10.70-74. I'm using ubuntu-14.04.1lts-minimal-odroid-c1-20150131 image.
Freezes are random - first time it happened 10 minutes after I first powered on odroid.

This exact time I had an USB TvTuner plugged in and I was tailing syslog and managed to capture the error output: http://pastebin.com/BT4fdqiL
The TvTuner is a Sundtek Media Pro II and when odroid froze, I was configuring TVHeadend and setting up the channels.
The mediasrv process appearing in the pastebin belongs to the tvtuner.

Besides the lan cable and the tvtuner, there's nothing else plugged in odroid.

Do those log errors provide any hints?

Thanks.

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Re: System freeze - kernel errors

Post by mdrjr »

What Power supply?

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Re: System freeze - kernel errors

Post by dkked »


bodgy
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Re: System freeze - kernel errors

Post by bodgy »

Have you checked the CPU temperature?

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Re: System freeze - kernel errors

Post by dkked »

No, mainly because it sits in a room where temps are 5-10 degrees Celsius.
I'll check them though and post back the results.

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Re: System freeze - kernel errors

Post by dkked »

Another freeze.

Temperature and cpu frequency exactly before freeze, as follows:
Date
CPU Freq
Temp
w (for load)

Code: Select all

Wed Mar 11 12:01:30 GMT 2015
1536Mhz
36000
 12:01:30 up  1:40,  1 user,  load average: 0.99, 0.78, 0.59

Wed Mar 11 12:01:32 GMT 2015
1536Mhz
34000
 12:01:32 up  1:40,  1 user,  load average: 0.99, 0.78, 0.59

Wed Mar 11 12:01:34 GMT 2015
1536Mhz
33000
 12:01:34 up  1:40,  1 user,  load average: 0.99, 0.78, 0.59

Wed Mar 11 12:01:36 GMT 2015
1536Mhz
33000
 12:01:36 up  1:40,  1 user,  load average: 0.91, 0.77, 0.59

Wed Mar 11 12:01:38 GMT 2015
1536Mhz
32000
 12:01:38 up  1:40,  1 user,  load average: 0.91, 0.77, 0.59

Wed Mar 11 12:01:40 GMT 2015
1536Mhz
33000
 12:01:40 up  1:40,  1 user,  load average: 1.00, 0.79, 0.60
Errors this time attached as picture.
Again, it complains about mediasrv process, it really doesn't like it. Is it maybe related to the usb driver?
Attachments
DSC01162.JPG
DSC01162.JPG (158.17 KiB) Viewed 2545 times

dkked
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Re: System freeze - kernel errors

Post by dkked »

I've chatted with the Sundtek software engineer (the guys who make the tv tuner) and he said their driver cannot possibly cause a kernel panic.
He pointed out that "Unable to handle kernel NULL pointer dereference at virtual address 00000001" is a kernel bug, probably in kmalloc and possibly related to the cpu scheduler.

I have now changed the scheduler from interactive to performance (echo performance > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor), on all cores, and am rerunning my tests. It's looking promising at the moment.
btw, just to be clear, mediasrv process is the driver talking to the usb controller.

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Re: System freeze - kernel errors

Post by sundtek »

We have seen such a problem earlier already, and it seems to be related with the CPU Scheduler driver.

2 Problems which we have seen in the past on some systems:
1. dynamically enabling/disabling CPU Cores
2. dynamically changing the frequency

I'm not sure what it is with the Odroid system but my guess is one of those 2 things cause problems on it. This is not only related to our driver this could happen just randomly during runtime. The Odroid team should really put some work into that and fix it - I would consider this as a very critical bug.

Our driver just helps to reproduce the Odroid bug, but it is not the reason.

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Re: System freeze - kernel errors

Post by dkked »

@sundtek thanks for pitching in, and for your support.

Indeed, since at the moment my only workload on the Odroid is the MediaPro tuner, it would be somewhat easy to conclude it is the problem. But if I would replace the workload with something else, I would definitely see these errors again.

Since changing the scheduler I haven't seen another freeze, yet:
# uptime
09:38:45 up 20:47

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