On Fri, Sep 27, 2019 at 10:24:49AM -0700, Eric Dumazet wrote:
>
>
> On 9/27/19 9:52 AM, Martin KaFai Lau wrote:
> > In reuseport_array_free(), the rcu_read_lock() cannot ensure sk is still
> > valid. It is because bpf_sk_reuseport_detach() can be called from
> > __sk_destruct() which is invoked through call_rcu(..., __sk_destruct).
>
> We could question why reuseport_detach_sock(sk) is called from __sk_destruct()
> (after the rcu grace period) instead of sk_destruct() ?
Agree. It is another way to fix it.
In this patch, I chose to avoid the need to single out a special treatment for
reuseport_detach_sock() in sk_destruct().
I am happy either way. What do you think?
>
> >
> > This patch takes the reuseport_lock in reuseport_array_free() which
> > is not the fast path. The lock is taken inside the loop in case
> > that the bpf map is big.
> >
> > Signed-off-by: Martin KaFai Lau <kafai@xxxxxx>
>
> Fixes: 5dc4c4b7d4e8 ("bpf: Introduce BPF_MAP_TYPE_REUSEPORT_SOCKARRAY")
Ah...missed that. Thanks!
