Re: [PATCH net] bonding: Fix bonding crash

On Fri, 2016-09-02 at 08:57 -0600, David Ahern wrote:

I hit this same problem yesterday but with the bridge. I forgot I had
a macvlan device on an interface and tried to enslave it to a bridge.
It failed with EBUSY without crashing the kernel so it is one example
that handles the conflict, and the bridge also calls the register
before the enslaving is done.

Sure, some netdev_rx_handler_register() users are simpler than bonding,
this was the point Jiri raised. Hey guys just use team instead of
bonding ;)

If you carefully look at bridge code, you'll find other kind of errors
for sure ;)

For example, should dev_disable_lro() be called before or after
netdev_rx_handler_register()  ? ;)

Mahesh proposal allows for simplification, since one level can be
removed from the error rollback chain.

Ideally the netdev_rx_handler_register() should be called only when no
further errors can be detected in the 'enslaving' process, otherwise
some live packets could come and be incorrectly processed/dropped by a
not fully initialized driver.

So it is a chicken and egg problem, if you allow
netdev_rx_handler_register() to return an error, while it is so easy
to early check what could go wrong with it.