Re: [PATCH] netlink: fix memory leak of dump

[Florian Westphal]

shaochun chen <cscnull@xxxxxxxxx> wrote:
> I have a question: we will try_module_get in __netlink_dump_start(),

Thats too late, we release rcu read lock before this, so the module
implementing ->dump might have been removed already.

> but why we need to call try_module_get again in  nft_netlink_dump_start ??

Its the other way around.
This is the first try_module_get; at this point we still hold rcu read
lock.

If nf_tables module is being removed, try_module_get will fail and
we can error out.

If it succeeds, its safe to drop the rcu read lock.