Fxp / polling / witness panic

[John Baldwin]

On 08-May-2003 Robin P. Blanchard wrote:
> Latest sources with following debugging options set yields the panic below.
> 
> makeoptions     DEBUG=-g
> options         KTRACE
> options         DDB
> options         DDB_UNATTENDED
> options         ALT_BREAK_TO_DEBUGGER
> options         INVARIANTS
> options         INVARIANT_SUPPORT
> options         WITNESS
> options         WITNESS_SKIPSPIN
> 
>#0  doadump () at /usr/src/sys/kern/kern_shutdown.c:238
> 238             dumping++;
> (kgdb) bt
>#0  doadump () at /usr/src/sys/kern/kern_shutdown.c:238
>#1  0xc01d8133 in boot (howto=256) at /usr/src/sys/kern/kern_shutdown.c:370
>#2  0xc01d847b in panic () at /usr/src/sys/kern/kern_shutdown.c:543
>#3  0xc01fb681 in witness_lock (lock=0xc1526160, flags=8, 
>     file=0xc0308197 "/usr/src/sys/dev/fxp/if_fxp.c", line=1465)
>     at /usr/src/sys/kern/subr_witness.c:722

What is the actual panic?

Is it this one?

KASSERT((lock1->li_lock->lo_flags & LO_WITNESS) == 0,
    ("lock missing witness structure"));

Looks like the lock may be used after it was destroyed or some such.

-- 

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