DDESCRIPTION:
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During the ixgbe reload stress test, a new duplicated entry is added to the 70-persistent-net.rules file located (/etc/udev/rules.d/70-persistent-net.rules). The newly added interface (eth4) has the same MAC address as a currently existing interface (eth3).

Syslog reports that udev renamed eth3 to eth4:
Apr  3 03:29:14 linstd49 kernel: udev: renamed network interface eth3 to eth4
udevd-work[13866]: error changing netif name 'eth3' to 'eth4': No such device
These events are repeated in syslog through the stress test. 


# PCI device 0x8086:0x1096 (e1000e) (custom name provided by external tool)
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="00:30:48:7f:26:ce", ATTR{type}=="1", KERNEL=="eth*", NAME="eth0"
# PCI device 0x8086:0x10fb (ixgbe) (custom name provided by external tool)
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="00:1b:21:55:23:b1", ATTR{type}=="1", KERNEL=="eth*", NAME="eth3"
# PCI device 0x8086:0x10fb (ixgbe) (custom name provided by external tool)
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="00:1b:21:55:23:b0", ATTR{type}=="1", KERNEL=="eth*", NAME="eth2"
# PCI device 0x8086:0x1096 (e1000e) (custom name provided by external tool)
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="00:30:48:7f:26:cf", ATTR{type}=="1", KERNEL=="eth*", NAME="eth1"
# PCI device 0x8086:0x10fb ()
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="00:1b:21:55:23:b1", KERNEL=="eth*", NAME="eth4"

There is no 5th interface (eth4) on the system, it was added erroneously during heavy ixgbe stress.

CONFIGURATION:
------------
Test Configuration:
Supermicro (System ID 14499),1 quad-core CPU, 8 GB RAM, dual-port Niantic, RHEL6.0-GA-x86_64 + errata updates


STEPS TO REPRODUCE:
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1.) while true ; do
        rmmod ixgbe ; modprobe ixgbe ;
done

RESULTS:
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Duplicate MAC address is used for a new eth4 entry in the 70-persistent-net.rules file. No eth4 exists on the system. The entry has the same mac as an already existing entry, eth3.

EXPECTED RESULTS:
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No new udev rules should be created or renamed for already existent ethernet interface/MAC address pairs in the 70-persistent-net.rules file.This appears to be Udev related.