witness patch

This gives a traceback when witness_warn() is called like when
we get a lock order reversal in witness_checkorder().

Please review or commit.


Index: subr_witness.c
===================================================================
RCS file: /home/ncvs/src/sys/kern/subr_witness.c,v
retrieving revision 1.170
diff -u -r1.170 subr_witness.c
--- subr_witness.c	27 Feb 2004 18:33:09 -0000	1.170
+++ subr_witness.c	15 Mar 2004 09:47:45 -0000
_at__at_ -1150,6 +1150,8 _at__at_
 #ifdef DDB
 	else if (witness_ddb && n)
 		Debugger(__func__);
+	else if (witness_trace && n)
+		backtrace();
 #endif
 	return (n);
 }