Re: NetworkManager not reliably starting ethernet interface directly wired between two computers

[Dan Williams <dcbw redhat com>]

On Wed, 2011-06-22 at 14:38 -0400, Douglas C. MacKenzie wrote:
> I have two computers that have a direct ethernet wire between them. The
> interface is set to a static ip address on each side, and under control
> of the NetworkManager.  The computers are on the same power supply and
> power up at the same time.

What kernel version?  There was a driver bug with 8169 initial carrier
in some older kernels that I think got fixed in 2.6.38 and maybe the
patch needs to be backported.

One thing to check is that when things don't work, try:

cat /sys/class/net/eth0/carrier

if that's "1" the kernel driver thinks you  have a carrier, if it's "0"
then it doesn't, and if the kernel doesn't think so, neither will NM.

Dan

> About 1/10 the time, the interface does not start. The messages log file
> will show:
> 
> Jun 22 13:01:22 owl10 NetworkManager[601]: <info> (p6p1): carrier is OFF
> Jun 22 13:01:22 owl10 NetworkManager[601]: <info> (p6p1): new Ethernet
> device (driver: 'r8169' ifindex: 2)
> Jun 22 13:01:22 owl10 NetworkManager[601]: <info> (p6p1): exported
> as /org/freedesktop/NetworkManager/Devices/0
> Jun 22 13:01:22 owl10 NetworkManager[601]: <info> (p6p1): now managed
> Jun 22 13:01:22 owl10 NetworkManager[601]: <info> (p6p1): device state
> change: unmanaged -> unavailable (reason 'managed') [10 20 2]
> Jun 22 13:01:22 owl10 NetworkManager[601]: <info> (p6p1): bringing up
> device.
> Jun 22 13:01:22 owl10 NetworkManager[601]: <info> (p6p1): preparing
> device.
> Jun 22 13:01:22 owl10 NetworkManager[601]: <info> (p6p1): deactivating
> device (reason: 2).
> Jun 22 13:01:22 owl10 kernel: [ 4.932240] r8169 0000:05:00.0: p6p1: link
> down
> Jun 22 13:01:22 owl10 kernel: [ 4.932248] r8169 0000:05:00.0: p6p1: link
> down
> Jun 22 13:01:22 owl10 kernel: [ 4.932634] ADDRCONF(NETDEV_UP): p6p1:
> link is not ready
> 
> 
> And, if I just physically unplug the cable and plug it back in
> NetworkManager starts the interface:
> 
> Jun 22 13:08:40 owl10 kernel: [ 442.658355] r8169 0000:05:00.0: p6p1:
> link up
> Jun 22 13:08:40 owl10 kernel: [ 442.658875] ADDRCONF(NETDEV_CHANGE):
> p6p1: link becomes ready
> Jun 22 13:08:40 owl10 NetworkManager[601]: <info> (p6p1): carrier now ON
> (device state 20)
> Jun 22 13:08:40 owl10 NetworkManager[601]: <info> (p6p1): device state
> change: unavailable -> disconnected (reason 'carrier-changed') [20 30
> 40]
> Jun 22 13:08:40 owl10 NetworkManager[601]: <info> Activation (p6p1)
> starting connection 'Middle Port'
> Jun 22 13:08:40 owl10 NetworkManager[601]: <info> (p6p1): device state
> change: disconnected -> prepare (reason 'none') [30 40 0]
> Jun 22 13:08:40 owl10 NetworkManager[601]: <info> Activation (p6p1)
> Stage 1 of 5 (Device Prepare) scheduled...
> Jun 22 13:08:40 owl10 NetworkManager[601]: <info> Activation (p6p1)
> Stage 1 of 5 (Device Prepare) started...
> Jun 22 13:08:40 owl10 NetworkManager[601]: <info> Activation (p6p1)
> Stage 2 of 5 (Device Configure) scheduled...
> Jun 22 13:08:40 owl10 NetworkManager[601]: <info> Activation (p6p1)
> Stage 1 of 5 (Device Prepare) complete.
> Jun 22 13:08:40 owl10 NetworkManager[601]: <info> Activation (p6p1)
> Stage 2 of 5 (Device Configure) starting...
> Jun 22 13:08:40 owl10 NetworkManager[601]: <info> (p6p1): device state
> change: prepare -> config (reason 'none') [40 50 0]
> Jun 22 13:08:40 owl10 NetworkManager[601]: <info> Activation (p6p1)
> Stage 2 of 5 (Device Configure) successful.
> Jun 22 13:08:40 owl10 NetworkManager[601]: <info> Activation (p6p1)
> Stage 3 of 5 (IP Configure Start) scheduled.
> Jun 22 13:08:40 owl10 NetworkManager[601]: <info> Activation (p6p1)
> Stage 2 of 5 (Device Configure) complete.
> Jun 22 13:08:40 owl10 NetworkManager[601]: <info> Activation (p6p1)
> Stage 3 of 5 (IP Configure Start) started...
> Jun 22 13:08:40 owl10 NetworkManager[601]: <info> (p6p1): device state
> change: config -> ip-config (reason 'none') [50 70 0]
> Jun 22 13:08:40 owl10 NetworkManager[601]: <info> Activation (p6p1)
> Stage 4 of 5 (IP4 Configure Get) scheduled...
> Jun 22 13:08:40 owl10 NetworkManager[601]: <info> Activation (p6p1)
> Stage 3 of 5 (IP Configure Start) complete.
> Jun 22 13:08:40 owl10 NetworkManager[601]: <info> Activation (p6p1)
> Stage 4 of 5 (IP4 Configure Get) started...
> Jun 22 13:08:40 owl10 NetworkManager[601]: <info> Activation (p6p1)
> Stage 5 of 5 (IP Configure Commit) scheduled...
> Jun 22 13:08:40 owl10 NetworkManager[601]: <info> Activation (p6p1)
> Stage 4 of 5 (IP4 Configure Get) complete.
> Jun 22 13:08:40 owl10 NetworkManager[601]: <info> Activation (p6p1)
> Stage 5 of 5 (IP Configure Commit) started...
> Jun 22 13:08:40 owl10 avahi-daemon[614]: Joining mDNS multicast group on
> interface p6p1.IPv4 with address 192.168.3.10.
> Jun 22 13:08:40 owl10 avahi-daemon[614]: New relevant interface
> p6p1.IPv4 for mDNS.
> Jun 22 13:08:40 owl10 avahi-daemon[614]: Registering new address record
> for 192.168.3.10 on p6p1.IPv4.
> Jun 22 13:08:41 owl10 NetworkManager[601]: <info> Policy set 'Side
> Port' (p7p1) as default for IPv4 routing and DNS.
> Jun 22 13:08:41 owl10 NetworkManager[601]: <info> (p6p1): device state
> change: ip-config -> activated (reason 'none') [70 100 0]
> Jun 22 13:08:41 owl10 NetworkManager[601]: <info> Activation (p6p1)
> successful, device activated.
> Jun 22 13:08:41 owl10 NetworkManager[601]: <info> Activation (p6p1)
> Stage 5 of 5 (IP Configure Commit) complete.
> 
> 
> So, I imagine there is a race condition where both boxes wait for the
> other to start the interface and provide a carrier.  Is that likely the
> problem?
> 
> If so, is there a way to force NetworkManager to bring up an interface
> even if there is no Carrier?  Or, is it a kernel issue.
> 
> BTW, this problem started recently on Fedora 13 after some upgrades. We
> upgraded to the latest Fedora 15 to try and solve it, and it now appears
> more often than it did on Fedora 13.  It is happening on two different
> pairs of computers, with different cables, so I doubt it is a hardware
> problem.
> 
> Doug
> 
> 
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