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Commit a5b5bb9a053a973c23b867738c074acb3e80c0a0

Authored by Ingo Molnar
Committed by Linus Torvalds
1 parent 0afffc723c
Exists in master and in 7 other branches imx_3.0.35_4.1.0, imx_3.10.17_1.0.1_ga, imx_3.10.53_1.1.0_ga, imx_3.14.28_1.0.0_ga, smarc-imx_3.10.53_1.1.0_ga, smarc-imx_3.14.28_1.0.0_ga, smarc-l5.0.0_1.0.0-ga

[PATCH] lockdep: annotate sk_locks 

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 <mingo@elte.hu>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

Showing 2 changed files with 98 additions and 19 deletions Side-by-side Diff

... ... @@ -44,6 +44,7 @@
44 44 #include <linux/timer.h>
45 45 #include <linux/cache.h>
46 46 #include <linux/module.h>
  47 +#include <linux/lockdep.h>
47 48 #include <linux/netdevice.h>
48 49 #include <linux/skbuff.h> /* struct sk_buff */
49 50 #include <linux/security.h>
50 51  
... ... @@ -78,17 +79,16 @@
78 79 spinlock_t slock;
79 80 struct sock_iocb *owner;
80 81 wait_queue_head_t wq;
  82 + /*
  83 + * We express the mutex-alike socket_lock semantics
  84 + * to the lock validator by explicitly managing
  85 + * the slock as a lock variant (in addition to
  86 + * the slock itself):
  87 + */
  88 +#ifdef CONFIG_DEBUG_LOCK_ALLOC
  89 + struct lockdep_map dep_map;
  90 +#endif
81 91 } socket_lock_t;
82   -
83   -extern struct lock_class_key af_family_keys[AF_MAX];
84   -
85   -#define sock_lock_init(__sk) \
86   -do { spin_lock_init(&((__sk)->sk_lock.slock)); \
87   - lockdep_set_class(&(__sk)->sk_lock.slock, \
88   - af_family_keys + (__sk)->sk_family); \
89   - (__sk)->sk_lock.owner = NULL; \
90   - init_waitqueue_head(&((__sk)->sk_lock.wq)); \
91   -} while(0)
92 92  
93 93 struct sock;
94 94 struct proto;
... ... @@ -133,9 +133,44 @@
133 133 * Each address family might have different locking rules, so we have
134 134 * one slock key per address family:
135 135 */
136   -struct lock_class_key af_family_keys[AF_MAX];
  136 +static struct lock_class_key af_family_keys[AF_MAX];
  137 +static struct lock_class_key af_family_slock_keys[AF_MAX];
137 138  
  139 +#ifdef CONFIG_DEBUG_LOCK_ALLOC
138 140 /*
  141 + * Make lock validator output more readable. (we pre-construct these
  142 + * strings build-time, so that runtime initialization of socket
  143 + * locks is fast):
  144 + */
  145 +static const char *af_family_key_strings[AF_MAX+1] = {
  146 + "sk_lock-AF_UNSPEC", "sk_lock-AF_UNIX" , "sk_lock-AF_INET" ,
  147 + "sk_lock-AF_AX25" , "sk_lock-AF_IPX" , "sk_lock-AF_APPLETALK",
  148 + "sk_lock-AF_NETROM", "sk_lock-AF_BRIDGE" , "sk_lock-AF_ATMPVC" ,
  149 + "sk_lock-AF_X25" , "sk_lock-AF_INET6" , "sk_lock-AF_ROSE" ,
  150 + "sk_lock-AF_DECnet", "sk_lock-AF_NETBEUI" , "sk_lock-AF_SECURITY" ,
  151 + "sk_lock-AF_KEY" , "sk_lock-AF_NETLINK" , "sk_lock-AF_PACKET" ,
  152 + "sk_lock-AF_ASH" , "sk_lock-AF_ECONET" , "sk_lock-AF_ATMSVC" ,
  153 + "sk_lock-21" , "sk_lock-AF_SNA" , "sk_lock-AF_IRDA" ,
  154 + "sk_lock-AF_PPPOX" , "sk_lock-AF_WANPIPE" , "sk_lock-AF_LLC" ,
  155 + "sk_lock-27" , "sk_lock-28" , "sk_lock-29" ,
  156 + "sk_lock-AF_TIPC" , "sk_lock-AF_BLUETOOTH", "sk_lock-AF_MAX"
  157 +};
  158 +static const char *af_family_slock_key_strings[AF_MAX+1] = {
  159 + "slock-AF_UNSPEC", "slock-AF_UNIX" , "slock-AF_INET" ,
  160 + "slock-AF_AX25" , "slock-AF_IPX" , "slock-AF_APPLETALK",
  161 + "slock-AF_NETROM", "slock-AF_BRIDGE" , "slock-AF_ATMPVC" ,
  162 + "slock-AF_X25" , "slock-AF_INET6" , "slock-AF_ROSE" ,
  163 + "slock-AF_DECnet", "slock-AF_NETBEUI" , "slock-AF_SECURITY" ,
  164 + "slock-AF_KEY" , "slock-AF_NETLINK" , "slock-AF_PACKET" ,
  165 + "slock-AF_ASH" , "slock-AF_ECONET" , "slock-AF_ATMSVC" ,
  166 + "slock-21" , "slock-AF_SNA" , "slock-AF_IRDA" ,
  167 + "slock-AF_PPPOX" , "slock-AF_WANPIPE" , "slock-AF_LLC" ,
  168 + "slock-27" , "slock-28" , "slock-29" ,
  169 + "slock-AF_TIPC" , "slock-AF_BLUETOOTH", "slock-AF_MAX"
  170 +};
  171 +#endif
  172 +
  173 +/*
139 174 * sk_callback_lock locking rules are per-address-family,
140 175 * so split the lock classes by using a per-AF key:
141 176 */
142 177  
... ... @@ -249,9 +284,16 @@
249 284 skb->dev = NULL;
250 285  
251 286 bh_lock_sock(sk);
252   - if (!sock_owned_by_user(sk))
  287 + if (!sock_owned_by_user(sk)) {
  288 + /*
  289 + * trylock + unlock semantics:
  290 + */
  291 + mutex_acquire(&sk->sk_lock.dep_map, 0, 1, _RET_IP_);
  292 +
253 293 rc = sk->sk_backlog_rcv(sk, skb);
254   - else
  294 +
  295 + mutex_release(&sk->sk_lock.dep_map, 1, _RET_IP_);
  296 + } else
255 297 sk_add_backlog(sk, skb);
256 298 bh_unlock_sock(sk);
257 299 out:
... ... @@ -761,6 +803,33 @@
761 803 return 0;
762 804 }
763 805  
  806 +/*
  807 + * Initialize an sk_lock.
  808 + *
  809 + * (We also register the sk_lock with the lock validator.)
  810 + */
  811 +static void inline sock_lock_init(struct sock *sk)
  812 +{
  813 + spin_lock_init(&sk->sk_lock.slock);
  814 + sk->sk_lock.owner = NULL;
  815 + init_waitqueue_head(&sk->sk_lock.wq);
  816 + /*
  817 + * Make sure we are not reinitializing a held lock:
  818 + */
  819 + debug_check_no_locks_freed((void *)&sk->sk_lock, sizeof(sk->sk_lock));
  820 +
  821 + /*
  822 + * Mark both the sk_lock and the sk_lock.slock as a
  823 + * per-address-family lock class:
  824 + */
  825 + lockdep_set_class_and_name(&sk->sk_lock.slock,
  826 + af_family_slock_keys + sk->sk_family,
  827 + af_family_slock_key_strings[sk->sk_family]);
  828 + lockdep_init_map(&sk->sk_lock.dep_map,
  829 + af_family_key_strings[sk->sk_family],
  830 + af_family_keys + sk->sk_family);
  831 +}
  832 +
764 833 /**
765 834 * sk_alloc - All socket objects are allocated here
766 835 * @family: protocol family
767 836  
768 837  
769 838  
... ... @@ -1465,24 +1534,34 @@
1465 1534 void fastcall lock_sock(struct sock *sk)
1466 1535 {
1467 1536 might_sleep();
1468   - spin_lock_bh(&(sk->sk_lock.slock));
  1537 + spin_lock_bh(&sk->sk_lock.slock);
1469 1538 if (sk->sk_lock.owner)
1470 1539 __lock_sock(sk);
1471 1540 sk->sk_lock.owner = (void *)1;
1472   - spin_unlock_bh(&(sk->sk_lock.slock));
  1541 + spin_unlock(&sk->sk_lock.slock);
  1542 + /*
  1543 + * The sk_lock has mutex_lock() semantics here:
  1544 + */
  1545 + mutex_acquire(&sk->sk_lock.dep_map, 0, 0, _RET_IP_);
  1546 + local_bh_enable();
1473 1547 }
1474 1548  
1475 1549 EXPORT_SYMBOL(lock_sock);
1476 1550  
1477 1551 void fastcall release_sock(struct sock *sk)
1478 1552 {
1479   - spin_lock_bh(&(sk->sk_lock.slock));
  1553 + /*
  1554 + * The sk_lock has mutex_unlock() semantics:
  1555 + */
  1556 + mutex_release(&sk->sk_lock.dep_map, 1, _RET_IP_);
  1557 +
  1558 + spin_lock_bh(&sk->sk_lock.slock);
1480 1559 if (sk->sk_backlog.tail)
1481 1560 __release_sock(sk);
1482 1561 sk->sk_lock.owner = NULL;
1483   - if (waitqueue_active(&(sk->sk_lock.wq)))
1484   - wake_up(&(sk->sk_lock.wq));
1485   - spin_unlock_bh(&(sk->sk_lock.slock));
  1562 + if (waitqueue_active(&sk->sk_lock.wq))
  1563 + wake_up(&sk->sk_lock.wq);
  1564 + spin_unlock_bh(&sk->sk_lock.slock);
1486 1565 }
1487 1566 EXPORT_SYMBOL(release_sock);
1488 1567