Re: [PATCH] inet_diag: make config INET_DIAG bool

于 2012年09月24日 17:42, Eric Dumazet 写道:

In fact I didnt fully understand the problem you try to address.

If you want to prevent module being unloaded, you need to add proper
module_get()/module_put()

So I would add a "struct module *module;" in struct sock_diag_handler
and use it appropriately.

Yes, I try to add reference of the module,but I can't find a proper
location to call module_get and module_put.

module_get should be called when userspace program use netlink to
send dump request to the kernel,and module_put should be called when
the dump is completed. I am right?

BUT the userspace program may only call netlink_sendmsg without call
netlink_recvmsg.so the reference of the module will be incorrect.

But then, I might have totally misunderstood the problem.

Care to explain how you trigger the bug ?

It's very easy to trigger this bug,
you can exec "while :; do ss -a ; done" in one terminal
and exec "while :; do rmmod tcp_diag && rmmod inet_diag; done"
in another terminal.