Hello,
On 31.03.2016 21:21, David Miller wrote:
From: Daniel Borkmann <dan...@iogearbox.net>
Date: Thu, 31 Mar 2016 14:16:18 +0200
On 03/31/2016 01:59 PM, Eric Dumazet wrote:
On Thu, 2016-03-31 at 13:35 +0200, Daniel Borkmann wrote:
+static inline bool sock_owned_externally(const struct sock *sk)
+{
+ return sk->sk_flags & (1UL << SOCK_EXTERNAL_OWNER);
+}
+
Have you reinvented sock_flag(sl, SOCK_EXTERNAL_OWNER) ? ;)
Anyway, using a flag for this purpose sounds overkill to me.
Right.
Setting it is a way to 'fool' lockdep anyway...
Yep, correct, we'd be fooling the tun case, so this diff doesn't
really make it any better there.
I like the currently proposed patch where TUN says that RTNL is what
the synchronizing element is.
Maybe we could make a helper of some sort but since we only have once
case like this is just overkill.
Alexei, do you really mind if I apply Danile's patch?
I proposed the following patch to Daniel and he seemed to like it. I
was just waiting for his feedback and tags and wanted to send it out
then.
What do you think?
lockdep_sock_is_held does also have some other applications in other
parts of the source.
Bye,
Hannes
diff --git a/include/net/sock.h b/include/net/sock.h
index 255d3e03727b73..651b84a38cfb9b 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -1330,6 +1330,12 @@ static inline void sock_release_ownership(struct
sock *sk)
sk->sk_lock.owned = 0;
}
+static inline bool lockdep_sock_is_held(struct sock *sk)
+{
+ return lockdep_is_held(&sk->sk_lock) ||
+ lockdep_is_held(&sk->sk_lock.slock);
+}
+
/*
* Macro so as to not evaluate some arguments when
* lockdep is not enabled.
diff --git a/net/core/filter.c b/net/core/filter.c
index 4b81b71171b4ce..8ab270d5ce5507 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -1166,7 +1166,8 @@ static int __sk_attach_prog(struct bpf_prog *prog,
struct sock *sk)
}
old_fp = rcu_dereference_protected(sk->sk_filter,
- sock_owned_by_user(sk));
+ lockdep_rtnl_is_held() ||
+ lockdep_sock_is_held(sk));
rcu_assign_pointer(sk->sk_filter, fp);
if (old_fp)
@@ -2259,7 +2260,9 @@ int sk_detach_filter(struct sock *sk)
return -EPERM;
filter = rcu_dereference_protected(sk->sk_filter,
- sock_owned_by_user(sk));
+ lockdep_rtnl_is_held() ||
+ lockdep_sock_is_held(sk));
+
if (filter) {
RCU_INIT_POINTER(sk->sk_filter, NULL);
sk_filter_uncharge(sk, filter);
c
