panic: bufwrite: buffer is not busy???

[Eugene Grosbein]

On 31.01.2011 22:46, John Baldwin wrote:

>># gdb kernel
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>> This GDB was configured as "amd64-marcel-freebsd"...
>> (gdb) l *0xffffffff803c1315
>> 0xffffffff803c1315 is in ng_address_hook 
> (/home/src/sys/netgraph/ng_base.c:3504).
>> 3499             * Quick sanity check..
>> 3500             * Since a hook holds a reference on it's node, once we know
>> 3501             * that the peer is still connected (even if invalid,) we 
> know
>> 3502             * that the peer node is present, though maybe invalid.
>> 3503             */
>> 3504            if ((hook == NULL) ||
>> 3505                NG_HOOK_NOT_VALID(hook) ||
>> 3506                NG_HOOK_NOT_VALID(peer = NG_HOOK_PEER(hook)) ||
>> 3507                NG_NODE_NOT_VALID(peernode = NG_PEER_NODE(hook))) {
>> 3508                    NG_FREE_ITEM(item);
> 
> Hmmm.  I think you might have a hardware problem.  Notice the fault address, 
> it is 0x200000030.  Can you do 'x/i <instruction pointer>'?

(gdb) x/i 0xffffffff803c1315
0xffffffff803c1315 <ng_address_hook+37>:        testb  $0x1,0x28(%rdx)
(gdb) x/i *0xffffffff803c1315
0x12842f6:      Cannot access memory at address 0x12842f6

> I suspect it is 
> doing a memory access from that has a constant offset of 0x30, in which case 
> the original pointer was 0x200000000, meaning it would be NULL except it has a 
> single-bit error.  That would likely be caused by a hardware issue such as 
> failing RAM, etc.

This is SuperMicro server with ECC RAM. I've already tested it with memtest86+
during long time, no memory problems found.

Eugene Grosbein