According to comments above, clone the bug to udev component, if it is in wrong component, please move this bug to the right component

I don't know of any mechanism in the udev package, which modprobes a module on removal.

Might be a hotplug script from another package...

[root@dhcp-66-83-36 ~]# modprobe -r igb
[root@dhcp-66-83-36 ~]# 
[root@dhcp-66-83-36 ~]# 
[root@dhcp-66-83-36 ~]# 
[root@dhcp-66-83-36 ~]# 
[root@dhcp-66-83-36 ~]# dmesg 
ACPI: PCI interrupt for device 0000:09:00.1 disabled
switch: port 1(eth0) entering disabled state
device eth0 left promiscuous mode
switch: port 1(eth0) entering disabled state
ACPI: PCI interrupt for device 0000:09:00.0 disabled
dca service started, version 1.8
802.1Q VLAN Support v1.8 Ben Greear <greearb>
All bugs added by David S. Miller <davem>
Intel(R) Gigabit Ethernet Network Driver - version 2.1.0-k2-1
Copyright (c) 2007-2009 Intel Corporation.
PCI: Enabling device 0000:09:00.0 (0000 -> 0002)
ACPI: PCI Interrupt 0000:09:00.0[A] -> Link [LN48] -> GSI 48 (level, high) -> IRQ 51
PCI: Setting latency timer of device 0000:09:00.0 to 64
igb 0000:09:00.0: 0 vfs allocated
igb 0000:09:00.0: Intel(R) Gigabit Ethernet Network Connection
igb 0000:09:00.0: eth0: (PCIe:2.5Gb/s:Width x4) 00:1b:21:36:79:f0
igb 0000:09:00.0: eth0: PBA No: e43709-003
igb 0000:09:00.0: Using MSI-X interrupts. 4 rx queue(s), 1 tx queue(s)
PCI: Enabling device 0000:09:00.1 (0000 -> 0002)
ACPI: PCI Interrupt 0000:09:00.1[B] -> Link [LN49] -> GSI 49 (level, high) -> IRQ 107
PCI: Setting latency timer of device 0000:09:00.1 to 64
igb 0000:09:00.1: 0 vfs allocated
igb 0000:09:00.1: Intel(R) Gigabit Ethernet Network Connection
igb 0000:09:00.1: eth1: (PCIe:2.5Gb/s:Width x4) 00:1b:21:36:79:f1
igb 0000:09:00.1: eth1: PBA No: e43709-003
igb 0000:09:00.1: Using MSI-X interrupts. 4 rx queue(s), 1 tx queue(s)
ADDRCONF(NETDEV_UP): eth0: link is not ready
device eth0 entered promiscuous mode
igb: eth0 NIC Link is Up 1000 Mbps Full Duplex, Flow Control: RX
ADDRCONF(NETDEV_CHANGE): eth0: link becomes ready
switch: topology change detected, propagating
switch: port 1(eth0) entering forwarding state
[root@dhcp-66-83-36 ~]# lsmod | grep igb
igb                   128213  0 
8021q                  57937  1 igb
dca                    41605  1 igb

Hi Harald, 
  I have seen this issue in Rhel6-snapshot4 timeframe.

On RHEL5.6-Snapshot4 , unload the igb driver and then reload igb driver with max_vfs option then igb driver fails to unload. We have not seen this issue in 5.6 GA. 

Could update on what fix went in regarding this.

thanks.

(In reply to comment #9)
> Hi Harald, 
>   I have seen this issue in Rhel6-snapshot4 timeframe.
> 
> On RHEL5.6-Snapshot4 , unload the igb driver and then reload igb driver with
> max_vfs option then igb driver fails to unload. We have not seen this issue in
> 5.6 GA. 
> 
> Could update on what fix went in regarding this.
> 
> thanks.

So, you are saying this issue is fixed? I didn't change anything in this regard.

Anyway, module removal is not and will not be supported.