Question on device events and unregister_netdev.
Subsystems (2)
Hello!
I'm working on stacking some virtual interfaces, and ran into a problem with locking.
Basically, I have an ethernet-like device, and on top of that I am putting 802.1Q vlans..and on top of that, some other vlan (macvlan).
In the event notifier for the vlan, I attempt to delete all vlans who's under-lying device is going away. I do the same for the macvlan.
Currently, I am setting a deadlock warning because the macvlan code is calling unregister_netdev, but the 'rmmod' method already has a lock in there due to having earlier called unregister_netdev on the .1q vlan.
So, the question is: Should I be calling unregister_netdev from the notifier callback?
Thanks,
Ben
Signature · 2 lines
Ben Greear <[email protected]> Candela Technologies Inc http://www.candelatech.com
David Miller
maintainerFrom: Ben Greear <[email protected]>
Date: Tue, 11 Jul 2006 16:27:25 -0700
Quoted 2 lines
So, the question is: Should I be calling
unregister_netdevfrom the notifier callback?
Not really, as you saw it can be deadlock prone.
One idea is to run the unregister asynchronously via a workqueue. That should be able to get you out of the deadlock.
Quoted 4 lines · David Miller
From: Ben Greear <[email protected]>
Date: Tue, 11 Jul 2006 16:27:25 -0700
Quoted 8 lines
Quoted 2 lines
So, the question is: Should I be calling
unregister_netdevfrom the notifier callback?Not really, as you saw it can be deadlock prone.
One idea is to run the unregister asynchronously via a workqueue. That should be able to get you out of the deadlock.
After more poking, I notice that 802.1q uses unregister_netdevice, which does not grab rtnl. It seems that the notifiers are always called with rtnl asserted. That would be a recursive call to unregister_netdevice, however...any reason that won't work?
Ben
Signature · 2 lines
Ben Greear <[email protected]> Candela Technologies Inc http://www.candelatech.com