Re: [PATCH net 1/2] net: ethernet: ftgmac100: prevent use after free on unregister when using NCSI

[Jeremy Kerr <jk@codeconstruct.com.au>]

Hi all,

[+Sam, as ncsi maintainer]

> So, this worth a try with the _remove sequence reordered with respect
> to the ncsi device. I'll work on a replacement patch to see if that
> can be done without other fallout, and will send a follow-up soon.

OK, not so simple. ftgmac100_probe does a:
  
    ncsi_register_dev()
      -> dev_add_pack()
    register_netdev()

- where ptype.dev is the ftgmac netdev.

So we'd want to restructure the _remove to do:

    unregister_netdev()
    ncsi_unregister_dev()
     -> dev_remove_pack()

However, we (sensibly) can't do the unregister_netdev() with a
packet-type handler still in place.

Sam: would it make sense to move the dev_add_pack() / dev_remove_pack()
to the ncsi layer's ncsi_start_dev() / ncsi_stop_dev() ? The channel
monitor is disabled on stop, so we shouldn't expect to receive any
further NCSI ethertype packets.

Cheers,


Jeremy