4BSD Scheduler Problem on 5.3

John Baldwin jhb at FreeBSD.org
Thu Mar 31 15:07:01 PST 2005


On Thursday 31 March 2005 03:38 pm, William Michael Grim wrote:
> Hello.
>
> I keep having kernel panics every couple weeks on my system.  It occurs in
> the sched_switch() function.  There are several other statements in the
> backtrace involving "??"; what are those?
>
> I have attached the dump output and system info to this email.  Any
> feedback would be helpful.
>
> Thanks so much for your help.

The real trace ends with Xint0x80_syscall().  The rest after that is garbage 
memory.  Your real problem is in exit1() or ttywakeup().  Since ttywakeup() 
doesn't call exit1() (AFAIK), the exit1() frame is probably bogus (gdb 
doesn't grok trapframes maybe?) and the real bug is a NULL pointer deref in 
ttywakeup().  Perhaps it's a bug in the ptc driver?  (ptcopen is in the 
trace).  What is the ptc driver anyway?

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


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