panic on vm_page_cache_transfer: object 0xfffffff0035508000's type is not compatible with cache pages

[Willem Jan Withagen]

On 2011-03-08 15:15, John Baldwin wrote:
> On Tuesday, March 08, 2011 5:54:36 am Willem Jan Withagen wrote:
>> System:
>>
>> FreeBSD zfs.digiware.nl 8.2-STABLE FreeBSD 8.2-STABLE #1: Sat Feb 26
>> 06:28:43 CET 2011
>> root at zfs.digiware.nl:/usr/obj/usr/src/src8/src/sys/ZFS  amd64
>>
>> Don't have a serial console, so I wrote down the traceback.
>> But my guess is that that is not enough, however I needed the system so
>> I rebooted.
>>
>> tb:
>> vm_object_split		at .... +0x125
>> vm_space_fork		at .... +0x3f7
>> fork1			at .... +0x6a9
>> fork			at .... +0xee
>> syscall_entr		at ....	+1c
>> syscall			at ....	+4c
>>
>> rip = 0x8006bc39c
>> rsp = 0x7fffffffe9d8
>> rbp = 0x800a04470
>>
>> It looks a lot like what I find on
>> http://people.freebsd.org/~pho/stress/log/kostik079.html
>>
>> But my system is amd64, with 8Gb RAM and is fully ZFS based
>> with swap on 2 gpt freebsd-swap partitions.
>>
>> System crashed last night around 1:30, which is when a few large rsync
>> backups are coming in.
>>
>> Would I be able to call doadump to obtain something usefull afterward
>> (provided I have savecore set?)
>
> Hmm, judging from the info at the URL above, I'm not sure what to make of this
> assertion.  In vm_object_split(), the 'new_object' is always OBJT_DEFAULT, so
> it will always fail that half of the assertion.  In fact, this is the only
> place that vm_page_cache_transfer() is called, so 'new_object->type ==
> OBJT_SWAP' is pretty much guaranteed to almost never be true.
>
> I guess it is assuming that swap_pager_copy() would have always converted
> 'new_object' to OBJT_SWAP if it had any cache pages?  Perhaps that is a bogus
> assumption if 'orig_object' only has cache pages and no currently-swapped out
> pages (or if the swapped out pages are not in the range of the new object)?
>
> I've cc'd Alan to see if he has any ideas.

Well, given enough time it does return.
Found my server at the debug prompt again.

So suggestion are still welcome.

Thanx,
--WjW