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Re: disappointing upgrade to NetBSD 5.0

On Tue, 26 May 2009 05:40:04 -0700, Jean-Yves Migeon <> wrote:

Dan Engholm wrote:
I can't be sure what I am doing to get the problem to occur, but it seems
to be network related.  Looking around Google, I found one thread in
port-xen with a similar description but it dead ended with no resolution. (see

It is network related, but the error is due to the hypervisor returning an error for the decrease memory operation. As the domU does not expect it to fail, it ends in panic().

Advice would be the same as in the link above: any error reported by the hypervisor on its console?

The console doesn't show anything when the panic occurs. I don't have a terminal on the serial port but my xconsole shows XEN related messages so I'm assuming that is where I would see something related to this problem, too. Here is what I see while the user domain is starting up:

xvif2.0: Ethernet address aa:00:00:51:02:f0
May 26 18:39:11 xxxxxx routed[227]: Send bcast sendto(xvif2.0, Network is down
xbd backend: attach device wd1b (size 2097152) for domain 2
xbd backend: attach device raid2f (size 209715200) for domain 2
xbd backend: attach device raid1f (size 4194304) for domain 2
xvif2.0 using event channel 17
xbd backend 0 for domain 2 using event channel 18

Building databases:panic: buf mem pool index 7
Begin traceback...
uvm_fault(0xc9d58b98, 0, 1) -> 0xe
fatal page fault in supervisor mode
trap type 6 code 0 eip c0396531 cs 9 eflags 10246 cr2 0 ilevel 0
panic: trap
Faulted in mid-traceback; aborting...
dumping to dev 142,16 offset 1582223
dump device bad
 What it should have said after "Building databases:" is:
 Building databases: dev, utmp, utmpx done
Starting syslogd.
Setting date via ntp.
Checking for core dump...

Any chance we could get a backtrace?

For that, edit the /etc/sysctl.conf of domU, set the ddb.onpanic to 1. Then "bt" from ddb prompt.

panic: Unable to reduce memory reservation

fatal breakpoint trap in supervisor mode
trap type 1 code 0 eip c039504c cs 9 eflags 246 cr2 0 ilevel 4
Stopped in pid 579.1 (Xvnc) at  netbsd:breakpoint+0x4:  popl    %ebp
db> BT
No such command: BT
db> bt
breakpoint(c044097b,cb5cdae8,c0455bc0,c03a0011,ca217000,c049f440,cb5cdb1c,c049f440,1,2) at netbsd:breakpoint+0x4 panic(c04431b4,5108,5a8,c03a905a,c9d3e6ca,cb5cdc7c,cb371280,c02e3a06,caa4d043,bfbfe30d) at netbsd:panic+0x1a6 xen_network_handler(0,0,cb5cdb4c,c02ccedb,4,caa3b000,caa4d000,c0b96600,c03b0400,c0b8aa2c) at netbsd:xen_network_handler xennet_rx_mbuf_free(c0b96600,caa4d000,4c,ca217f10,50435051,0,cb5cdb7c,13a8fa7,c0b96600,c0b8aae4) at netbsd:xennet_rx_mbuf_free+0x44 m_ext_free(c0b96600,0,cb5cdc7c,0,0,cb53e2c0,3,9,5cdbd4,cb53e2c0) at netbsd:m_ext_free+0x8b soreceive(c0b8aa2c,0,cb5cdc7c,0,0,0,cb5cdcac,c0308303,cb5fed10,cb5fed10) at netbsd:soreceive+0xbc4 soo_read(cb5fed10,cb5fed10,cb5cdc7c,cb570528,1,cb5cdce0,c0102cf5,cb5cdc74,6,c9d40011) at netbsd:soo_read+0x34 dofileread(9,cb5fed10,bfbfe30d,9,cb5fed10,1,cb5cdd28,0,cb53e2c0,0) at netbsd:dofileread+0x73 sys_read(cb53e2c0,cb5cdd00,cb5cdd28,200203,1,fffffffe,0,9,bfbfe30d,9) at netbsd:sys_read+0x6f syscall(cb5cdd48,cf001f,bfbf001f,816001f,bfbf001f,bfbfe824,9,bfbfe1d8,9,9) at netbsd:syscall+0xc7

Since the upgrade, my user domain no longer boots without intervention. It
does not figure out on its own where the root partition is so I have to
manually enter "xbd0a" from the Xen console.  The configuration file has
'root = "/dev/xbd0a"' in it as it has since I started using Xen. This is
true regardless of which version of Xen I use.

And with root = "xbd0" ?

Specifying 'root = "xbd0a"' seemed to fix this problem.  Thanks.

Also, I got burned by Xen telling me that the "nics" configuration option is obsolete. The man page says that it's still valid and that its default value is 1. If I don't have a "nics = 1" line in my configuration file, no
NICs are created and the creation fails because it can't configure the
network.  What gives?

vif array?

vif = ['mac=00:16:3e:00:00:11, bridge=bridge0'] # for example

I don't get this one. I could not create the user domain until I put 'nics = 1' in but now I have it commented out and it works just fine. *sigh*

The saga continues.  See my follow-up to the other reply.


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