Re: Xen3 domU crashes

[Manuel Bouyer <bouyer%antioche.eu.org@localhost>]

On Fri, May 11, 2007 at 09:52:39AM +0300, Martti Kuparinen wrote:
> Here the normal XEN3_DOMU after installation. I added 8 interfaces to my 
> confuration file and it crashed like this. Is there anything else you'd 
> like to know?
> 
> 
> xennet7 at xenbus0 id 7: Xen Virtual Network Interface
> xennet7: MAC address 00:16:3e:00:00:05
> xennet7: using event channel 13
> panic: xbdstart: xengnt_grant_access
> Stopped in pid 4.1 (xenwatch) at        netbsd:cpu_Debugger+0x4:        
> popl    %
> ebp
> db> bt
> cpu_Debugger(c0410c0e,ca93b9e8,7338,58d5c000,c0fb18f4) at 
> netbsd:cpu_Debugger+0x
> 4
> panic(c0412007,58d5c000,0,c0fb18f4,0) at netbsd:panic+0x155
> xbdstart(c0fb103c,ca94df04,ca93ba9c,ca94df04,8) at netbsd:xbdstart+0x512
> dk_start(c04421d0,c0fb103c,0,c02990a3,0) at netbsd:dk_start+0x3e
> dk_strategy(c04421d0,c0fb103c,ca94df04,c02e7a5c,ca94bd4c) at 
> netbsd:dk_strategy+
> 0x13e
> xbdstrategy(ca94df04,ca94bd4c,0,c0fc8600,ca93bb9c) at 
> netbsd:xbdstrategy+0x69
> read_sector(0,0,ca93bb1c,c02f865a,0) at netbsd:read_sector+0x6a
> scan_mbr(400,2,ca93bbdc,c02d636c,c0457080) at netbsd:scan_mbr+0x39
> readdisklabel(3,c03a0dd0,c0fc8600,c0fc8400,0) at netbsd:readdisklabel+0xdc
> dk_getdisklabel(c04421d0,c0fb103c,0,c0fb193c,a) at 
> netbsd:dk_getdisklabel+0xa8
> xbd_backend_changed(c0fb1000,4,2,0,0) at netbsd:xbd_backend_changed+0x1f5
> xenwatch_thread(ca94bd4c,0,c01001e7,c01001df,c01001e7) at 
> netbsd:xenwatch_thread
> +0x94
> db>

Thanks, this confirms that we're running out of grant entries. As I said
we can't do much at this point because Xen up to 3.0.4 hardcode the
number of grant pages to 4. We could rebuild a xen.gz kernel with this
number bumped to 8 or 16, and bump it the same way on NetBSD, but I
think it's easier to decrease the number of receive buffers for
xennet, at this point. The next Xen release may allow us handle this better ...

-- 
Manuel Bouyer, LIP6, Universite Paris VI.           
Manuel.Bouyer%lip6.fr@localhost
     NetBSD: 26 ans d'experience feront toujours la difference
--