Re: [PATCH] media: au0828: Convert BUG_ON to WARN_ONCE

[Larry Finger <Larry.Finger@lwfinger.net>]

On 04/08/2012 08:46 PM, Devin Heitmueller wrote:
> On Sun, Apr 8, 2012 at 7:19 PM, Larry Finger<Larry.Finger@lwfinger.net>  wrote:
>> In the mail thread at http://www.mythtv.org/pipermail/mythtv-users/2012-April/331164.html,
>> a kernel crash is triggered when trying to run mythtv with a HVR950Q tuner.
>> The crash condition is due to res_free() being called to free something that
>> has is not reserved. The actual reason for this mismatch of reserve/free is
>> not known; however, using a BUG_ON rather than a WARN_ON seems unfortunate.
>
> This patch should be nack'd.  The real reason should be identified,
> and a patch should be submitted for that (and from what I gather, it
> seems like it is easily reproduced by the submitter).  Just add a few
> "dump_stack()" calls in the res_get() and res_free() calls to identify
> the failing call path.

I agree that we need to find the real cause; however, I am not the one with the 
problem, and I do not have the hardware. In addition, I am not sure how much 
additional debug information the person will be able to provide. He has not 
built Linux kernels since 1.2. If he can get a kernel built, then we will try to 
find the real cause.

In any case, why the reluctance to get rid of the BUG_ON? Is this condition so 
severe that the kernel needs to be stopped immediately?

Larry