[ale] checking for process in uninterruptable sleep state

[Todor Fassl]

Just a followup to let you know that the fix Phil suggests below appears 
to have worked. I added "usbcore.autosuspend=-1" to the default kernel 
parms in grub and we haven't had a machine hang because of an 
uninterruptable system call for a week.

On 05/10/2016 02:29 PM, Todor Fassl wrote:
> [Sorry to top post but I am blind and it is very difficult for me to 
> post in-line.]
>
> These workstations are in a lab and students  are plugging usb devices 
> into them all the time. I was checking the logs on one machine last 
> week and I saw that somebody had plugged a web cam in. I am guessing 
> it was for skype and/or linphone. I will never be able to pin it down 
> to a specific usb device.
>
> But every time a machine is hung, it is always that same file, 
> /sys/bus/usb/devices/usb1/descriptors, that causes it to go into an 
> uninterruptable sleep. So I think the defective usb device is the usb 
> controller itself.
>
> Well, I set the kernel parameter to disable usb autosuspend. I'll post 
> back if it works. I did manage to write a script to notifiy me when 
> the problem occurs so if the script doesn't trigger in a couple of 
> days, I'm going to say it's fixed.
>
>
>
>
>
> On 05/10/2016 10:16 AM, Phil Turmel wrote:
>> On 05/10/2016 10:39 AM, Todor Fassl wrote:
>>> Details: I have 15 Dell workstations running ubuntu 15.10 (2 are 
>>> running
>>> 16.04 -- that did not help). Occasionally, the keyboard and mouse
>>> freeze. Logging in remotely and running lsusb hangs such that you can't
>>> even control-c outand it cannot be killed even with a -9. The process
>>> goes into an uninterruptable sleep during a system call to open the 
>>> file
>>> /sys/bus/usb/devices/usb1/descriptors. That file is part of the 
>>> kernel's
>>> control files for the usb controller itself. So you can see why the
>>> keyboard and mouse are dead, the driver for the usb controller 
>>> itself is
>>> hung.
>>
>>> PS: I wouldn't mind ideas wrt the original problem either. Not that I
>>> hold out any hope for that.
>>
>> Ah, you have buggy USB devices.  I've run into this.  I used the kernel
>> boot parameter usbcore.autosuspend=-1 to globally disable USB per-device
>> power saving on my mythtv server.  If you can narrow it down to a
>> specific set of devices, you could create udev rules to prevent just
>> those from sleeping.
>>
>> Some links:
>>
>> http://unix.stackexchange.com/questions/91027/how-to-disable-usb-autosuspend-on-kernel-3-7-10-or-above 
>>
>>
>> http://askubuntu.com/questions/80638/how-to-disable-auto-power-off-of-usb-devices-like-usb-mouse 
>>
>>
>> Phil
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>