[pvrusb2] CPU Run pvrusb2-context

[Roger]

On Thu, Oct 14, 2010 at 09:15:41PM -0500, Mike Isely wrote:
>On Thu, 14 Oct 2010, rogerx at sdf.org wrote:
>
>> I encountered a CPU run with rmmod pvrusb2 and then several seconds later
>> modprobing pvrusb2.
>> 
>> From what top shows, pvrusb2-context either hung on modprobe or rmmod.
>> 
>> 
>> # tail /var/log/everything/current  -n 20
>> Oct 14 00:53:36 [kernel] tda18271 0-0060: creating new instance
>> Oct 14 00:53:36 [kernel] TDA18271HD/C1 detected @ 0-0060
>> Oct 14 00:53:37 [kernel] tda829x 0-0042: type set to tda8295+18271
>> Oct 14 00:53:40 [kernel] usb 3-4: firmware: requesting v4l-cx2341x-enc.fw
>> Oct 14 00:53:41 [kernel] pvrusb2: firmware2 upload transfer failure
>> Oct 14 00:53:41 [kernel] pvrusb2: Clearing driver error statuss
>> Oct 14 00:53:43 [kernel] cx25840 0-0044: 0x0000 is not a valid video input!
>> Oct 14 00:53:43 [kernel] DVB: registering adapter 0 frontend 0 (Samsung S5H1411
>> QAM/8VSB Frontend)...
>> Oct 14 00:53:43 [kernel] tda829x 0-0042: type set to tda8295
>> Oct 14 00:53:43 [kernel] tda18271 0-0060: attaching existing instance
>> Oct 14 00:53:47 [kernel] usbcore: deregistering interface driver pvrusb2
>> Oct 14 00:53:47 [kernel] pvrusb2: Device being rendered inoperable
>
>
>> Oct 14 00:53:47 [kernel] pvrusb2: unregistered device ■■■o0 [mpeg]
>
>This line is the key.  Notice the garbage characters in place of the 
>device name.  What's happened is that the printk which generated this 
>line referenced deallocated memory - because it had earlier been freed 
>as part of the driver tear-down.  This is one of the bugs that I stomped 
>out last Spring (by reordering the tear-down steps slightly to avoid 
>this case).

Yup. After grabbing the dmesg log, I noticed the garbage chars and suspected
something odd like that, but you're the expert -- and I today noticed your
Changelog entry on this bug.

>
>I don't think you're running the latest driver.
>
>
>> Oct 14 00:53:47 [kernel] pvrusb2: unregistering DVB devices
>> Oct 14 00:54:02 [kernel] SysRq : Emergency Sync
>>                 - Last output repeated 2 times -
>> 
>> 
>> Top shows:
>> PID   USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+   COMMAND
>> 26142 root      20   0     0    0    0 R  100  0.0    5:31.30 pvrusb2-context
>> 4085  roger     39  19  2636 1188  904 S    1  0.1    4:12.39 top
>> 26299 root      20   0  2656 1176  896 R    1  0.1    0:00.04 top
>> 
>> (I've have to re-enable pvrusb2 mailing list to start sending mailing list emails.)
>
>Two things here:
>
>1. The mailing list software will disable a subscriber if his address 
>creates too many bounces.  Note that once a month the list software 
>sends out a reminder that you're subscribed along with instructions (as 
>a reminder) for unsubscribing if you so choose.  If that reminder gets 
>bounced, then it counts against you - and I've seen a lot of bounces 
>because people seem to have overly aggressive filters that treat the 
>reminder as junk.
>
>2. You posted from an address that I think is different than what you've 
>used in the past.  There's no way the mailing list software can infer 
>two addresses are related so if you wanted to post from another address 
>you would also have to subscribe from it first.

I purposely deactivated/suspended receiving mailing list emails.  I wasn't
sure how long it would be to re-enable, so I made a note here I might not see
follow-ups just in case.

-- 
Roger
http://rogerx.freeshell.org/