Bug 226960

Description of problem:
eth0 and eth1 are connected to independent unmanaged switches through backbone
to gateway. When the uplink of the switches are broken only 1 interface detects it:
bonding: bond0: backup interface eth0 is now down
bonding: bond0: backup interface eth0 is now up

If bonding module is reloaded it's 50/50 chance it's this or the other interface
detecting upstream link breakage.

Consequence: high availability is reduced, since if  uplink in the unmonitored
path breaks the operating system does not detect it, and system goes offline.

Manually failing over active interface works as expected:
real:~# ifenslave -c bond0 eth0
real:~# fping ping.uio.no
ping.uio.no is alive
real:~# ifenslave -c bond0 eth1
real:~# fping ping.uio.no
ping.uio.no is alive

Im thinking it's a) the lack of arp_validate in the current redhat kernel, since
there is a lot of arp traffic on these unmanaged swithces even when they have no
uplink, 
http://article.gmane.org/gmane.linux.kernel.commits.head/87685/match=bonding+arp
or it is some specific x86_64 bug like
http://article.gmane.org/gmane.linux.kernel.commits.mm/3877/match=arp+monitoring+broken+x86+64

Version-Release number of selected component (if applicable):
real:~# uname -a
Linux real 2.6.9-42.0.8.ELsmp #1 SMP Tue Jan 23 12:49:51 EST 2007 x86_64 x86_64
x86_64 GNU/Linux


How reproducible:
always

Steps to Reproduce:
1. break uplink from unmanaged switch a
2. wait for bonding code reaction

  
Actual results:
No response on 1 of 2 interfaces

Expected results:
bonding code response on both interfaces

Additional info:

configuration
real:~# cat /etc/modprobe.conf
alias bond0 bonding
options bond0 mode=active-backup arp_interval=1000 arp_ip_target= 80.232.38.65 \ 
primary=eth1
alias eth0 e1000
alias eth1 e1000

real:~# cat /etc/sysconfig/network-scripts/ifcfg-bond0 
DEVICE=bond0
BOOTPROTO=static
BROADCAST=80.232.38.127
IPADDR=80.232.38.80
NETMASK=255.255.255.192
NETWORK=80.232.38.64
GATEWAY=80.232.38.65
ONBOOT=yes
BONDING_MASTER="yes"
BONDING_SLAVE0="eth0"
BONDING_SLAVE1="eth1" 

real:~# cat /etc/sysconfig/network-scripts/ifcfg-eth[0,1]
DEVICE=eth0
USERCTL=no
BOOTPROTO=none
ONBOOT=yes
MASTER=bond0
SLAVE=yes
DEVICE=eth1
USERCTL=no
BOOTPROTO=none
ONBOOT=yes
MASTER=bond0
SLAVE=yes
real:~# cat /proc/net/bonding/bond0 
Ethernet Channel Bonding Driver: v2.6.3 (June 8, 2005)

Bonding Mode: fault-tolerance (active-backup)
Primary Slave: eth1
Currently Active Slave: eth1
MII Status: up
MII Polling Interval (ms): 0
Up Delay (ms): 0
Down Delay (ms): 0

Slave Interface: eth0
MII Status: up
Link Failure Count: 4
Permanent HW addr: 00:14:4f:01:90:80

Slave Interface: eth1
MII Status: up
Link Failure Count: 1
Permanent HW addr: 00:14:4f:01:90:81

Please let me know if I can provide any more details or if there is some more
testing I should do.