Commit 61881cfb authored Apr 05, 2016 by Hannes Frederic Sowa Committed by David S. Miller Apr 07, 2016

sock: fix lockdep annotation in release_sock



During release_sock we use callbacks to finish the processing
of outstanding skbs on the socket. We actually are still locked,
sk_locked.owned == 1, but we already told lockdep that the mutex
is released. This could lead to false positives in lockdep for
lockdep_sock_is_held (we don't hold the slock spinlock during processing
the outstanding skbs).

I took over this patch from Eric Dumazet and tested it.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 85017869

include/net/sock.h

+6 −1

Original line number	Diff line number	Diff line
		@@ -1333,7 +1333,12 @@ static inline void sk_wmem_free_skb(struct sock sk, struct sk_buff skb)

		static inline void sock_release_ownership(struct sock *sk)
		{
		if (sk->sk_lock.owned) {
		sk->sk_lock.owned = 0;

		/* The sk_lock has mutex_unlock() semantics: */
		mutex_release(&sk->sk_lock.dep_map, 1, _RET_IP_);
		}
		}

		/*

net/core/sock.c

+0 −5

Original line number	Diff line number	Diff line
		@@ -2483,11 +2483,6 @@ EXPORT_SYMBOL(lock_sock_nested);

		void release_sock(struct sock *sk)
		{
		/*
		* The sk_lock has mutex_unlock() semantics:
		*/
		mutex_release(&sk->sk_lock.dep_map, 1, _RET_IP_);

		spin_lock_bh(&sk->sk_lock.slock);
		if (sk->sk_backlog.tail)
		__release_sock(sk);