debugging 6.1 crash

[Stephen Clark]

Hello List,

I am trying to debug a 6.1 panic. When I run kgdb kernel.debug 
/var/crash/vmcore.7 all I get is:

kgdb: kvm_read: invalid address (0x24)
kgdb: kvm_read: invalid address (0x24)
kgdb: kvm_read: invalid address (0x24)
kgdb: kvm_read: invalid address (0x24)
kgdb: kvm_read: invalid address (0x24)
kgdb: kvm_read: invalid address (0x24)
kgdb: kvm_read: invalid address (0x24)
...

the info file shows:
Dump header from device /dev/ad0s1b
  Architecture: i386
  Architecture Version: 2
  Dump Length: 116981760B (111 MB)
  Blocksize: 512
  Dumptime: Mon Feb  4 04:13:09 2008
  Hostname: G301482.netws.com
  Magic: FreeBSD Kernel Dump
  Version String: FreeBSD 6.1-STABLE #25: Wed Nov 14 10:30:01 EST 2007
    root at J301002.nwv01.com:/mnt/src/sys/i386/compile/WOLFPAC6SMP
  Panic String: page fault
  Dump Parity: 1156397610
  Bounds: 7
  Dump Status: good


Does my kernel.debug have to match exactly the crash file kernel. I have 
made the following change
to my kernel that the kernel.debug is based on.
--- route.h.orig        Tue Apr  4 22:07:23 2006
+++ route.h     Mon Dec 17 13:11:44 2007
@@ -289,6 +289,7 @@
 #define        RT_LOCK_INIT(_rt) \
        mtx_init(&(_rt)->rt_mtx, "rtentry", NULL, MTX_DEF | MTX_DUPOK)
 #define        RT_LOCK(_rt)            mtx_lock(&(_rt)->rt_mtx)
+#define        RT_TRYLOCK(_rt)         mtx_trylock(&(_rt)->rt_mtx)
 #define        RT_UNLOCK(_rt)          mtx_unlock(&(_rt)->rt_mtx)
 #define        RT_LOCK_DESTROY(_rt)    mtx_destroy(&(_rt)->rt_mtx)
 #define        RT_LOCK_ASSERT(_rt)     mtx_assert(&(_rt)->rt_mtx, MA_OWNED)
--- route.c.orig        Tue Oct 30 19:07:54 2007
+++ route.c     Mon Dec 17 15:13:20 2007
@@ -996,6 +996,7 @@
        struct radix_node_head *rnh = rt_tables[dst->sa_family];
        int dlen = SA_SIZE(dst), glen = SA_SIZE(gate);

+again:
        RT_LOCK_ASSERT(rt);

        /*
@@ -1029,7 +1030,15 @@
                        RT_REMREF(rt);
                        return (EADDRINUSE); /* failure */
                }
-               RT_LOCK(rt);
+               /*
+                * Try to reacquire the lock on rt, and if it fails,
+                * clean state and restart from scratch.
+                */
+               if (!RT_TRYLOCK(rt)) {
+                       RTFREE_LOCKED(gwrt);
+                       RT_LOCK(rt);
+                       goto again;
+               }
                /*
                 * If there is already a gwroute, then drop it. If we
                 * are asked to replace route with itself, then do

Thanks,
Steve

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