From fafc4e1ea1a4c1eb13a30c9426fb799f5efacbc3 Mon Sep 17 00:00:00 2001 From: Hannes Frederic Sowa Date: Fri, 8 Apr 2016 15:11:27 +0200 Subject: [PATCH] sock: tigthen lockdep checks for sock_owned_by_user sock_owned_by_user should not be used without socket lock held. It seems to be a common practice to check .owned before lock reclassification, so provide a little help to abstract this check away. Cc: linux-cifs@vger.kernel.org Cc: linux-bluetooth@vger.kernel.org Cc: linux-nfs@vger.kernel.org Signed-off-by: Hannes Frederic Sowa Signed-off-by: David S. Miller --- fs/cifs/connect.c | 4 ++-- include/net/sock.h | 44 ++++++++++++++++++++++++------------ net/bluetooth/af_bluetooth.c | 2 +- net/llc/llc_proc.c | 2 +- net/sunrpc/svcsock.c | 3 +-- net/sunrpc/xprtsock.c | 3 +-- 6 files changed, 35 insertions(+), 23 deletions(-) diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c index 6f62ac821a84..2e2e0a6242d6 100644 --- a/fs/cifs/connect.c +++ b/fs/cifs/connect.c @@ -2918,7 +2918,7 @@ static inline void cifs_reclassify_socket4(struct socket *sock) { struct sock *sk = sock->sk; - BUG_ON(sock_owned_by_user(sk)); + BUG_ON(!sock_allow_reclassification(sk)); sock_lock_init_class_and_name(sk, "slock-AF_INET-CIFS", &cifs_slock_key[0], "sk_lock-AF_INET-CIFS", &cifs_key[0]); } @@ -2927,7 +2927,7 @@ static inline void cifs_reclassify_socket6(struct socket *sock) { struct sock *sk = sock->sk; - BUG_ON(sock_owned_by_user(sk)); + BUG_ON(!sock_allow_reclassification(sk)); sock_lock_init_class_and_name(sk, "slock-AF_INET6-CIFS", &cifs_slock_key[1], "sk_lock-AF_INET6-CIFS", &cifs_key[1]); } diff --git a/include/net/sock.h b/include/net/sock.h index 81d6fecec0a2..baba58770ac5 100644 --- a/include/net/sock.h +++ b/include/net/sock.h @@ -1316,21 +1316,6 @@ static inline void sk_wmem_free_skb(struct sock *sk, struct sk_buff *skb) __kfree_skb(skb); } -/* Used by processes to "lock" a socket state, so that - * interrupts and bottom half handlers won't change it - * from under us. It essentially blocks any incoming - * packets, so that we won't get any new data or any - * packets that change the state of the socket. - * - * While locked, BH processing will add new packets to - * the backlog queue. This queue is processed by the - * owner of the socket lock right before it is released. - * - * Since ~2.3.5 it is also exclusive sleep lock serializing - * accesses from user process context. - */ -#define sock_owned_by_user(sk) ((sk)->sk_lock.owned) - static inline void sock_release_ownership(struct sock *sk) { if (sk->sk_lock.owned) { @@ -1403,6 +1388,35 @@ static inline void unlock_sock_fast(struct sock *sk, bool slow) spin_unlock_bh(&sk->sk_lock.slock); } +/* Used by processes to "lock" a socket state, so that + * interrupts and bottom half handlers won't change it + * from under us. It essentially blocks any incoming + * packets, so that we won't get any new data or any + * packets that change the state of the socket. + * + * While locked, BH processing will add new packets to + * the backlog queue. This queue is processed by the + * owner of the socket lock right before it is released. + * + * Since ~2.3.5 it is also exclusive sleep lock serializing + * accesses from user process context. + */ + +static inline bool sock_owned_by_user(const struct sock *sk) +{ +#ifdef CONFIG_LOCKDEP + WARN_ON(!lockdep_sock_is_held(sk)); +#endif + return sk->sk_lock.owned; +} + +/* no reclassification while locks are held */ +static inline bool sock_allow_reclassification(const struct sock *csk) +{ + struct sock *sk = (struct sock *)csk; + + return !sk->sk_lock.owned && !spin_is_locked(&sk->sk_lock.slock); +} struct sock *sk_alloc(struct net *net, int family, gfp_t priority, struct proto *prot, int kern); diff --git a/net/bluetooth/af_bluetooth.c b/net/bluetooth/af_bluetooth.c index 955eda93e66f..3df7aefb7663 100644 --- a/net/bluetooth/af_bluetooth.c +++ b/net/bluetooth/af_bluetooth.c @@ -65,7 +65,7 @@ static const char *const bt_slock_key_strings[BT_MAX_PROTO] = { void bt_sock_reclassify_lock(struct sock *sk, int proto) { BUG_ON(!sk); - BUG_ON(sock_owned_by_user(sk)); + BUG_ON(!sock_allow_reclassification(sk)); sock_lock_init_class_and_name(sk, bt_slock_key_strings[proto], &bt_slock_key[proto], diff --git a/net/llc/llc_proc.c b/net/llc/llc_proc.c index 1a3c7e0f5d0d..29c509c54bb2 100644 --- a/net/llc/llc_proc.c +++ b/net/llc/llc_proc.c @@ -195,7 +195,7 @@ static int llc_seq_core_show(struct seq_file *seq, void *v) timer_pending(&llc->pf_cycle_timer.timer), timer_pending(&llc->rej_sent_timer.timer), timer_pending(&llc->busy_state_timer.timer), - !!sk->sk_backlog.tail, !!sock_owned_by_user(sk)); + !!sk->sk_backlog.tail, !!sk->sk_lock.owned); out: return 0; } diff --git a/net/sunrpc/svcsock.c b/net/sunrpc/svcsock.c index 71d6072664d2..dadfec66dbd8 100644 --- a/net/sunrpc/svcsock.c +++ b/net/sunrpc/svcsock.c @@ -85,8 +85,7 @@ static void svc_reclassify_socket(struct socket *sock) { struct sock *sk = sock->sk; - WARN_ON_ONCE(sock_owned_by_user(sk)); - if (sock_owned_by_user(sk)) + if (WARN_ON_ONCE(!sock_allow_reclassification(sk))) return; switch (sk->sk_family) { diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c index c1fc7b20bbc1..d0756ac5c0f2 100644 --- a/net/sunrpc/xprtsock.c +++ b/net/sunrpc/xprtsock.c @@ -1880,8 +1880,7 @@ static inline void xs_reclassify_socket6(struct socket *sock) static inline void xs_reclassify_socket(int family, struct socket *sock) { - WARN_ON_ONCE(sock_owned_by_user(sock->sk)); - if (sock_owned_by_user(sock->sk)) + if (WARN_ON_ONCE(!sock_allow_reclassification(sock->sk))) return; switch (family) { -- 2.20.1