Fatal trap 12: page fault while in kernel mode

[John Baldwin]

On Friday 02 December 2005 05:00 am, Yuri Khotyaintsev wrote:
> I have the following panic occurring several times a week. The machine is
> an NFS server, and it usually panics early in the morning, when first
> people try to access it. After reboot it may work OK for 1-2 days, and then
> panics again. I have tried changing memory and replacing disk which was
> exported via NFS, but nothing helped :(
>
> Any suggestion on how to fix this panic will be very much appreciated !

This panic (in propagate_priority) is usually caused when a thread goes to 
sleep while holding a mutex (which is forbidden).  If you enable INVARIANTS 
and/or WITNESS you should get a better panic, and with WITNESS you will even 
be warned when a thread goes to sleep while holding a mutex.  However, these 
options do introduce considerable execution overhead, and sometimes that 
overhead changes the timing enough to hide the race. :(

-- 
John Baldwin <jhb at FreeBSD.org>  <><  http://www.FreeBSD.org/~jhb/
"Power Users Use the Power to Serve"  =  http://www.FreeBSD.org