Description of problem:
On our system, the ifenslave detach (ifenslave -d) as executed in ifup-eth and
ifdown-eth to set up and take down bonding hangs the machine. 

Version-Release number of selected component (if applicable):


How reproducible:
We are using 8139too and pegasus modules as eth0 and eth1 respectively.  We set
up bonding using a static IP and the machine will lock when bringing down the
interface.  Using dhcp it will also invoke "ifenslave -d" when bringing up the
interface and it will lock up there too.

Steps to Reproduce:
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Actual results:


Expected results:


Additional info:
It's easily fixed by using sysfs to detach the slave devices.  Maybe it's time
to update initscripts to use sysfs instead of ifenslave when setting up or
shutting down bonding devices??

I've updated ifup-eth where it starts bonding with dhcp and replaced "ifenslave
-d $DEV $DEVICE" with:
echo "-$DEVICE" > /sys/class/net/${DEV}/bonding/slaves

Also updated ifdown-eth and the line "/sbin/ifenslave -d ${MASTER} ${DEVICE}
2>/dev/null" with:
echo "-$DEVICE" > /sys/class/net/${MASTER}/bonding/slaves

I'm not sure what ifenslave does different exactly, but using sysfs to detach no
longer causes hangups on our system.