Date: Tue, 8 Mar 2011 09:15:29 -0500 From: John Baldwin <jhb@freebsd.org> To: freebsd-stable@freebsd.org Cc: Alan Cox <alc@freebsd.org>, Willem Jan Withagen <wjw@digiware.nl> Subject: Re: panic on vm_page_cache_transfer: object 0xfffffff0035508000's type is not compatible with cache pages Message-ID: <201103080915.29284.jhb@freebsd.org> In-Reply-To: <4D760AEC.7050604@digiware.nl> References: <4D760AEC.7050604@digiware.nl>
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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@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. -- John Baldwin
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