From: Ingo Molnar Teach sk_lock semantics to the lock validator. In the softirq path the slock has mutex_trylock()+mutex_unlock() semantics, in the process context sock_lock() case it has mutex_lock()/mutex_unlock() semantics. Thus we treat sock_owned_by_user() flagged areas as an exclusion area too, not just those areas covered by a held sk_lock.slock. Effect on non-lockdep kernels: minimal, sk_lock_sock_init() has been turned into an inline function. Signed-off-by: Ingo Molnar Cc: Arjan van de Ven Cc: "David S. Miller" Cc: Herbert Xu Signed-off-by: Andrew Morton --- include/net/sock.h | 20 ++++----- net/core/sock.c | 92 ++++++++++++++++++++++++++++++++++++++----- 2 files changed, 93 insertions(+), 19 deletions(-) diff -puN include/net/sock.h~lockdep-annotate-sk_locks include/net/sock.h --- a/include/net/sock.h~lockdep-annotate-sk_locks +++ a/include/net/sock.h @@ -44,6 +44,7 @@ #include #include #include +#include #include #include /* struct sk_buff */ #include @@ -78,18 +79,17 @@ typedef struct { spinlock_t slock; struct sock_iocb *owner; wait_queue_head_t wq; + /* + * We express the mutex-alike socket_lock semantics + * to the lock validator by explicitly managing + * the slock as a lock variant (in addition to + * the slock itself): + */ +#ifdef CONFIG_DEBUG_LOCK_ALLOC + struct lockdep_map dep_map; +#endif } socket_lock_t; -extern struct lock_class_key af_family_keys[AF_MAX]; - -#define sock_lock_init(__sk) \ -do { spin_lock_init(&((__sk)->sk_lock.slock)); \ - lockdep_set_class(&(__sk)->sk_lock.slock, \ - af_family_keys + (__sk)->sk_family); \ - (__sk)->sk_lock.owner = NULL; \ - init_waitqueue_head(&((__sk)->sk_lock.wq)); \ -} while(0) - struct sock; struct proto; diff -puN net/core/sock.c~lockdep-annotate-sk_locks net/core/sock.c --- a/net/core/sock.c~lockdep-annotate-sk_locks +++ a/net/core/sock.c @@ -133,7 +133,40 @@ * Each address family might have different locking rules, so we have * one slock key per address family: */ -struct lock_class_key af_family_keys[AF_MAX]; +static struct lock_class_key af_family_keys[AF_MAX]; +static struct lock_class_key af_family_slock_keys[AF_MAX]; + +#ifdef CONFIG_LOCKDEP +/* + * Make lock validator output more readable: + */ +static const char *af_family_key_strings[AF_MAX+1] = { + "sk_lock-AF_UNSPEC", "sk_lock-AF_UNIX" , "sk_lock-AF_INET" , + "sk_lock-AF_AX25" , "sk_lock-AF_IPX" , "sk_lock-AF_APPLETALK", + "sk_lock-AF_NETROM", "sk_lock-AF_BRIDGE" , "sk_lock-AF_ATMPVC" , + "sk_lock-AF_X25" , "sk_lock-AF_INET6" , "sk_lock-AF_ROSE" , + "sk_lock-AF_DECnet", "sk_lock-AF_NETBEUI" , "sk_lock-AF_SECURITY" , + "sk_lock-AF_KEY" , "sk_lock-AF_NETLINK" , "sk_lock-AF_PACKET" , + "sk_lock-AF_ASH" , "sk_lock-AF_ECONET" , "sk_lock-AF_ATMSVC" , + "sk_lock-21" , "sk_lock-AF_SNA" , "sk_lock-AF_IRDA" , + "sk_lock-AF_PPPOX" , "sk_lock-AF_WANPIPE" , "sk_lock-AF_LLC" , + "sk_lock-27" , "sk_lock-28" , "sk_lock-29" , + "sk_lock-AF_TIPC" , "sk_lock-AF_BLUETOOTH", "sk_lock-AF_MAX" +}; +static const char *af_family_slock_key_strings[AF_MAX+1] = { + "slock-AF_UNSPEC", "slock-AF_UNIX" , "slock-AF_INET" , + "slock-AF_AX25" , "slock-AF_IPX" , "slock-AF_APPLETALK", + "slock-AF_NETROM", "slock-AF_BRIDGE" , "slock-AF_ATMPVC" , + "slock-AF_X25" , "slock-AF_INET6" , "slock-AF_ROSE" , + "slock-AF_DECnet", "slock-AF_NETBEUI" , "slock-AF_SECURITY" , + "slock-AF_KEY" , "slock-AF_NETLINK" , "slock-AF_PACKET" , + "slock-AF_ASH" , "slock-AF_ECONET" , "slock-AF_ATMSVC" , + "slock-21" , "slock-AF_SNA" , "slock-AF_IRDA" , + "slock-AF_PPPOX" , "slock-AF_WANPIPE" , "slock-AF_LLC" , + "slock-27" , "slock-28" , "slock-29" , + "slock-AF_TIPC" , "slock-AF_BLUETOOTH", "slock-AF_MAX" +}; +#endif /* * sk_callback_lock locking rules are per-address-family, @@ -249,9 +282,16 @@ int sk_receive_skb(struct sock *sk, stru skb->dev = NULL; bh_lock_sock(sk); - if (!sock_owned_by_user(sk)) + if (!sock_owned_by_user(sk)) { + /* + * trylock + unlock semantics: + */ + mutex_acquire(&sk->sk_lock.dep_map, 0, 1, _RET_IP_); + rc = sk->sk_backlog_rcv(sk, skb); - else + + mutex_release(&sk->sk_lock.dep_map, 1, _RET_IP_); + } else sk_add_backlog(sk, skb); bh_unlock_sock(sk); out: @@ -761,6 +801,30 @@ lenout: return 0; } +/* + * Initialize an sk_lock. + * + * (We also register the sk_lock with the lock validator.) + */ +static void inline sock_lock_init(struct sock *sk) +{ + spin_lock_init(&sk->sk_lock.slock); + lockdep_set_class_and_name(&sk->sk_lock.slock, + af_family_slock_keys + sk->sk_family, + af_family_slock_key_strings[sk->sk_family]); + sk->sk_lock.owner = NULL; + init_waitqueue_head(&sk->sk_lock.wq); +#ifdef CONFIG_DEBUG_LOCK_ALLOC + /* + * Make sure we are not reinitializing a held lock: + */ + debug_check_no_locks_freed((void *)&sk->sk_lock, sizeof(sk->sk_lock)); + lockdep_init_map(&sk->sk_lock.dep_map, + af_family_key_strings[sk->sk_family], + af_family_keys + sk->sk_family); +#endif +} + /** * sk_alloc - All socket objects are allocated here * @family: protocol family @@ -1465,24 +1529,34 @@ void sock_init_data(struct socket *sock, void fastcall lock_sock(struct sock *sk) { might_sleep(); - spin_lock_bh(&(sk->sk_lock.slock)); + spin_lock_bh(&sk->sk_lock.slock); if (sk->sk_lock.owner) __lock_sock(sk); sk->sk_lock.owner = (void *)1; - spin_unlock_bh(&(sk->sk_lock.slock)); + spin_unlock(&sk->sk_lock.slock); + /* + * The sk_lock has mutex_lock() semantics here: + */ + mutex_acquire(&sk->sk_lock.dep_map, 0, 0, _RET_IP_); + local_bh_enable(); } EXPORT_SYMBOL(lock_sock); void fastcall release_sock(struct sock *sk) { - spin_lock_bh(&(sk->sk_lock.slock)); + /* + * 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); sk->sk_lock.owner = NULL; - if (waitqueue_active(&(sk->sk_lock.wq))) - wake_up(&(sk->sk_lock.wq)); - spin_unlock_bh(&(sk->sk_lock.slock)); + if (waitqueue_active(&sk->sk_lock.wq)) + wake_up(&sk->sk_lock.wq); + spin_unlock_bh(&sk->sk_lock.slock); } EXPORT_SYMBOL(release_sock); _