[net-next PATCH 3/9] bpf: sockmap add missing rcu_read_(un)lock in smap_data_ready

John Fastabend
2017-08-28T14:10:59Z

References to psock must be done inside RCU critical section.

Fixes: 174a79ff9515 ("bpf: sockmap with sk redirect support")
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
---
kernel/bpf/sockmap.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/kernel/bpf/sockmap.c b/kernel/bpf/sockmap.c
index a6882e5..266011c8 100644
--- a/kernel/bpf/sockmap.c
+++ b/kernel/bpf/sockmap.c
@@ -227,11 +227,14 @@ static void smap_data_ready(struct sock *sk)
{
struct smap_psock *psock;

- write_lock_bh(&sk->sk_callback_lock);
+ rcu_read_lock();
psock = smap_psock_sk(sk);
- if (likely(psock))
+ if (likely(psock)) {
+ write_lock_bh(&sk->sk_callback_lock);
strp_data_ready(&psock->strp);
- write_unlock_bh(&sk->sk_callback_lock);
+ write_unlock_bh(&sk->sk_callback_lock);
+ }
+ rcu_read_unlock();
}

static void smap_tx_work(struct work_struct *w)