Re: zfs: Fatal trap 12: page fault while in kernel mode

On Aug 5, 2009, at 08:50, Pawel Jakub Dawidek wrote:

> On Fri, Jul 31, 2009 at 11:05:01AM +0200, Thomas Backman wrote:
>> I'm able to reliably reproduce this panic, by having zfs recv destroy
>> a filesystem on the receiving end.
>>
>> 1) Use DDEBUG=1, I guess
>> 2) Create a FS on the source pool you don't care about: zfs create -o
>> mountpoint=/testfs source/testfs
>> 3) Clone a pool to another: zfs snapshot -r source_at_snap && zfs send  
>> -R
>> source_at_snap | zfs recv -Fvd target
>> 4) zfs destroy -r source/testfs
>> 4) zfs snapshot -r source_at_snap2 && zfs send -R -I snap source_at_snap2 |
>> zfs recv -Fvd target
>> 5) ^ Panic while receiving the FS the destroyed one is mounted under.
>> In my case, this was tank/root three times out of three; I then tried
>> creating testfs under /tmp (tank/tmp/testfs), *mounting* it under / 
>> usr/
>> testfs, and it panics on receiving tank/usr:
> [...]
>
> I repeated precisevly those steps and it doesn't panic for me.
> Could you confirm that you use this patch?
>
> 	http://people.freebsd.org/~pjd/patches/zfs_vnops.c.2.patch
>
> If so, could you give me exact steps and all of them how to  
> reproduce it?
> Starting with pool creation.
Yup, I'm using that patch (I diffed the diffs, heh). I'll try to write  
a script to recreate the panic; I hope it's as easy as in real-world  
conditions though.

Regards,
Thomas