7.0 CURRENT kernel's ath driver causes page fault, kernel panic (debugging kernel)

[Edward Ruggeri]

On Fri, Jul 18, 2008 at 7:29 PM, Edward Ruggeri <smallhand at crawblog.com> wrote:
>> As for the actual debug process, there's a spot in the dev handbook
>> about it (http://www.freebsd.org/doc/en/books/developers-handbook/kerneldebug.html),
>> but when I tried debugging my issue with NTFS and SMB I didn't really
>> find it helpful to be honest...

AND

>> You may also have to compile without SMP and with the 4BSD scheduler
>> just to see whether or not it's an issue reproducible with the ULE
>> scheduler, the driver, or something else...

I have a couple dumps now, with different kernel configurations.  In
addition to the debugging options Garrett has recommended, I've
switched from the ULE to the 4BSD scheduler and removed SMP support.
The error persists.

The backtrace in kgdb says that panic is called from the function
ath_start at line 1748 in ath_start.c.  Here is a snippet:

bf = STAILQ_FIRST(&frags);
KASSERT(bf != NULL, ("no buf for txfrag"));

Does that sound like enough to file a problem report with?  What other
information would be desired?

-- Ned Ruggeri