Panic

[Robert Watson]

On Tue, 25 Jul 2006, Graham Menhennitt wrote:

>>> Fatal trap 12: page fault while in kernel mode
>>>> current process = 479 (mountd)
>>>>
>>
>> I have the same panic reproducibly. Shutting off nfs_server_enable (i.e. 
>> mountd) in rc.conf prevents it. This is with 6-STABLE cvsupped yesterday. 
>> I'll get some more info and follow up the PR.
>>
> I rebuilt my kernel (to enable debugging) and now it doesn't panic. So it 
> seems that an old kernel (from around the end of May) with a new mountd 
> (from Sunday) will crash. But a new kernel with a new mountd won't.

FYI, I've managed to reproduce this on a 7-CURRENT kernel, so will try to take 
a look at this in detail in the next few days.  It looks like a race during 
socket connect/accept for UNIX domain sockets, likely involving simultaneous 
close, which may be a sign of a bug in mountd (or the like) that triggers it. 
Of course, the kernel shouldn't panic under those circumstances. :-)

Thanks,

Robert N M Watson
Computer Laboratory
University of Cambridge