[pvrusb2] CPU Run pvrusb2-context

[Mike Isely]

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).

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.

  -Mike

-- 

Mike Isely
isely @ isely (dot) net
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