[PATCH v2 net-next] sock: relax WARN_ON() in sock_owned_by_user()

[Eric Dumazet]

From: Eric Dumazet <eduma...@google.com>

Valdis reported tons of stack dumps caused by WARN_ON() in
sock_owned_by_user()

This test needs to be relaxed if/when lockdep disables itself.

Note that other lockdep_sock_is_held() callers are all from
rcu_dereference_protected() sections which already are disabled
if/when lockdep has been disabled.

Fixes: fafc4e1ea1a4 ("sock: tigthen lockdep checks for sock_owned_by_user")
Reported-by: Valdis Kletnieks <valdis.kletni...@vt.edu>
Signed-off-by: Eric Dumazet <eduma...@google.com>
Acked-by: Hannes Frederic Sowa <han...@stressinduktion.org>
---
 include/net/sock.h |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/net/sock.h b/include/net/sock.h
index 52448baf19d7..2fdb87f176cf 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -1409,7 +1409,7 @@ static inline void unlock_sock_fast(struct sock *sk, bool 
slow)
 static inline bool sock_owned_by_user(const struct sock *sk)
 {
 #ifdef CONFIG_LOCKDEP
-       WARN_ON(!lockdep_sock_is_held(sk));
+       WARN_ON_ONCE(!lockdep_sock_is_held(sk) && debug_locks);
 #endif
        return sk->sk_lock.owned;
 }