mirror of https://lore.kernel.org/lkml/
 help / color / mirror / Atom feed
* [PATCH tip/core/rcu 0/8] rcu: add lockdep-based diagnostics to rcu_dereference()
@ 2010-01-05  2:03 Paul E. McKenney
  2010-01-05  2:04 ` [PATCH tip/core/rcu 1/8] rcu: introduce lockdep-based checking to RCU read-side primitives Paul E. McKenney
                   ` (8 more replies)
  0 siblings, 9 replies; 21+ messages in thread
From: Paul E. McKenney @ 2010-01-05  2:03 UTC (permalink / raw)
  To: linux-kernel
  Cc: mingo, laijs, dipankar, akpm, mathieu.desnoyers, josh, dvhltc,
	niv, tglx, peterz, rostedt, Valdis.Kletnieks, dhowells

Hello!

This patch series adds lockdep-based checking to the rcu_dereference()
primitive in order to flag misuses of RCU.  The first three patches
put the RCU infrastructure in place, while the last five use this
infrastructure in the net, sched, vfs, radix-tree, and idr subsystems.
There are very likely additional changes required.

							Thanx, Paul


 b/fs/file.c                     |    2 
 b/include/linux/cgroup.h        |    2 
 b/include/linux/cred.h          |    2 
 b/include/linux/fdtable.h       |    8 +-
 b/include/linux/rculist.h       |   14 ++--
 b/include/linux/rculist_nulls.h |    5 -
 b/include/linux/rcupdate.h      |  124 ++++++++++++++++++++++++++++++++++++----
 b/include/linux/srcu.h          |   87 +++++++++++++++++++++++++++-
 b/init/main.c                   |    2 
 b/kernel/exit.c                 |   14 +++-
 b/kernel/fork.c                 |    1 
 b/kernel/notifier.c             |    6 -
 b/kernel/pid.c                  |    2 
 b/kernel/rcupdate.c             |   10 +++
 b/kernel/rcutorture.c           |   12 +++
 b/kernel/sched.c                |    7 --
 b/kernel/srcu.c                 |   50 ++++++++++------
 b/lib/debug_locks.c             |    2 
 b/lib/idr.c                     |    9 +-
 b/lib/radix-tree.c              |   25 +++-----
 b/net/core/dev.c                |    2 
 b/net/core/filter.c             |    6 -
 b/net/core/sock.c               |    2 
 b/net/decnet/dn_route.c         |   14 ++--
 b/net/ipv4/route.c              |   14 ++--
 b/net/packet/af_packet.c        |    3 
 include/linux/rcupdate.h        |   45 ++++++++++----
 include/linux/srcu.h            |    9 ++
 28 files changed, 369 insertions(+), 110 deletions(-)

^ permalink raw reply	[flat|nested] 21+ messages in thread
* [PATCH tip/core/rcu 05/21] net: add checking to rcu_dereference() primitives
@ 2010-02-23  1:04 Paul E. McKenney
  2010-02-25 10:10 ` [tip:core/rcu] net: Add " tip-bot for Paul E. McKenney
  0 siblings, 1 reply; 21+ messages in thread
From: Paul E. McKenney @ 2010-02-23  1:04 UTC (permalink / raw)
  To: linux-kernel
  Cc: mingo, laijs, dipankar, akpm, mathieu.desnoyers, josh, dvhltc,
	niv, tglx, peterz, rostedt, Valdis.Kletnieks, dhowells,
	Paul E. McKenney

Update rcu_dereference() primitives to use new lockdep-based checking.
The rcu_dereference() in __in6_dev_get() may be protected either by
rcu_read_lock() or RTNL, per Eric Dumazet.  The rcu_dereference()
in __sk_free() is protected by the fact that it is never reached if an
update could change it.  Check for this by using rcu_dereference_check()
to verify that the struct sock's ->sk_wmem_alloc counter is zero.

Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
---
 include/linux/rtnetlink.h |    3 +++
 include/net/addrconf.h    |    4 +++-
 net/core/dev.c            |    2 +-
 net/core/filter.c         |    6 +++---
 net/core/rtnetlink.c      |    8 ++++++++
 net/core/sock.c           |    3 ++-
 net/decnet/dn_route.c     |   14 +++++++-------
 net/ipv4/route.c          |   14 +++++++-------
 net/packet/af_packet.c    |    2 +-
 9 files changed, 35 insertions(+), 21 deletions(-)

diff --git a/include/linux/rtnetlink.h b/include/linux/rtnetlink.h
index 05330fc..5c52fa4 100644
--- a/include/linux/rtnetlink.h
+++ b/include/linux/rtnetlink.h
@@ -735,6 +735,9 @@ extern void rtnl_lock(void);
 extern void rtnl_unlock(void);
 extern int rtnl_trylock(void);
 extern int rtnl_is_locked(void);
+#ifdef CONFIG_PROVE_LOCKING
+extern int lockdep_rtnl_is_held(void);
+#endif /* #ifdef CONFIG_PROVE_LOCKING */
 
 extern void rtnetlink_init(void);
 extern void __rtnl_unlock(void);
diff --git a/include/net/addrconf.h b/include/net/addrconf.h
index 0f7c378..45375b4 100644
--- a/include/net/addrconf.h
+++ b/include/net/addrconf.h
@@ -177,7 +177,9 @@ extern int unregister_inet6addr_notifier(struct notifier_block *nb);
 static inline struct inet6_dev *
 __in6_dev_get(struct net_device *dev)
 {
-	return rcu_dereference(dev->ip6_ptr);
+	return rcu_dereference_check(dev->ip6_ptr,
+				     rcu_read_lock_held() ||
+				     lockdep_rtnl_is_held());
 }
 
 static inline struct inet6_dev *
diff --git a/net/core/dev.c b/net/core/dev.c
index be9924f..0d0ff82 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -2041,7 +2041,7 @@ gso:
 	rcu_read_lock_bh();
 
 	txq = dev_pick_tx(dev, skb);
-	q = rcu_dereference(txq->qdisc);
+	q = rcu_dereference_bh(txq->qdisc);
 
 #ifdef CONFIG_NET_CLS_ACT
 	skb->tc_verd = SET_TC_AT(skb->tc_verd, AT_EGRESS);
diff --git a/net/core/filter.c b/net/core/filter.c
index 08db7b9..3541aa4 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -86,7 +86,7 @@ int sk_filter(struct sock *sk, struct sk_buff *skb)
 		return err;
 
 	rcu_read_lock_bh();
-	filter = rcu_dereference(sk->sk_filter);
+	filter = rcu_dereference_bh(sk->sk_filter);
 	if (filter) {
 		unsigned int pkt_len = sk_run_filter(skb, filter->insns,
 				filter->len);
@@ -521,7 +521,7 @@ int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk)
 	}
 
 	rcu_read_lock_bh();
-	old_fp = rcu_dereference(sk->sk_filter);
+	old_fp = rcu_dereference_bh(sk->sk_filter);
 	rcu_assign_pointer(sk->sk_filter, fp);
 	rcu_read_unlock_bh();
 
@@ -536,7 +536,7 @@ int sk_detach_filter(struct sock *sk)
 	struct sk_filter *filter;
 
 	rcu_read_lock_bh();
-	filter = rcu_dereference(sk->sk_filter);
+	filter = rcu_dereference_bh(sk->sk_filter);
 	if (filter) {
 		rcu_assign_pointer(sk->sk_filter, NULL);
 		sk_filter_delayed_uncharge(sk, filter);
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index 794bcb8..4c7d3f6 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -89,6 +89,14 @@ int rtnl_is_locked(void)
 }
 EXPORT_SYMBOL(rtnl_is_locked);
 
+#ifdef CONFIG_PROVE_LOCKING
+int lockdep_rtnl_is_held(void)
+{
+	return lockdep_is_held(&rtnl_mutex);
+}
+EXPORT_SYMBOL(lockdep_rtnl_is_held);
+#endif /* #ifdef CONFIG_PROVE_LOCKING */
+
 static struct rtnl_link *rtnl_msg_handlers[NPROTO];
 
 static inline int rtm_msgindex(int msgtype)
diff --git a/net/core/sock.c b/net/core/sock.c
index e1f6f22..305cba4 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -1073,7 +1073,8 @@ static void __sk_free(struct sock *sk)
 	if (sk->sk_destruct)
 		sk->sk_destruct(sk);
 
-	filter = rcu_dereference(sk->sk_filter);
+	filter = rcu_dereference_check(sk->sk_filter,
+				       atomic_read(&sk->sk_wmem_alloc) == 0);
 	if (filter) {
 		sk_filter_uncharge(sk, filter);
 		rcu_assign_pointer(sk->sk_filter, NULL);
diff --git a/net/decnet/dn_route.c b/net/decnet/dn_route.c
index a032840..a7bf03c 100644
--- a/net/decnet/dn_route.c
+++ b/net/decnet/dn_route.c
@@ -1155,8 +1155,8 @@ static int __dn_route_output_key(struct dst_entry **pprt, const struct flowi *fl
 
 	if (!(flags & MSG_TRYHARD)) {
 		rcu_read_lock_bh();
-		for(rt = rcu_dereference(dn_rt_hash_table[hash].chain); rt;
-			rt = rcu_dereference(rt->u.dst.dn_next)) {
+		for (rt = rcu_dereference_bh(dn_rt_hash_table[hash].chain); rt;
+			rt = rcu_dereference_bh(rt->u.dst.dn_next)) {
 			if ((flp->fld_dst == rt->fl.fld_dst) &&
 			    (flp->fld_src == rt->fl.fld_src) &&
 			    (flp->mark == rt->fl.mark) &&
@@ -1618,9 +1618,9 @@ int dn_cache_dump(struct sk_buff *skb, struct netlink_callback *cb)
 		if (h > s_h)
 			s_idx = 0;
 		rcu_read_lock_bh();
-		for(rt = rcu_dereference(dn_rt_hash_table[h].chain), idx = 0;
+		for(rt = rcu_dereference_bh(dn_rt_hash_table[h].chain), idx = 0;
 			rt;
-			rt = rcu_dereference(rt->u.dst.dn_next), idx++) {
+			rt = rcu_dereference_bh(rt->u.dst.dn_next), idx++) {
 			if (idx < s_idx)
 				continue;
 			skb_dst_set(skb, dst_clone(&rt->u.dst));
@@ -1654,12 +1654,12 @@ static struct dn_route *dn_rt_cache_get_first(struct seq_file *seq)
 
 	for(s->bucket = dn_rt_hash_mask; s->bucket >= 0; --s->bucket) {
 		rcu_read_lock_bh();
-		rt = dn_rt_hash_table[s->bucket].chain;
+		rt = rcu_dereference_bh(dn_rt_hash_table[s->bucket].chain);
 		if (rt)
 			break;
 		rcu_read_unlock_bh();
 	}
-	return rcu_dereference(rt);
+	return rt;
 }
 
 static struct dn_route *dn_rt_cache_get_next(struct seq_file *seq, struct dn_route *rt)
@@ -1674,7 +1674,7 @@ static struct dn_route *dn_rt_cache_get_next(struct seq_file *seq, struct dn_rou
 		rcu_read_lock_bh();
 		rt = dn_rt_hash_table[s->bucket].chain;
 	}
-	return rcu_dereference(rt);
+	return rcu_dereference_bh(rt);
 }
 
 static void *dn_rt_cache_seq_start(struct seq_file *seq, loff_t *pos)
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index e446496..3476b3b 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -287,12 +287,12 @@ static struct rtable *rt_cache_get_first(struct seq_file *seq)
 		if (!rt_hash_table[st->bucket].chain)
 			continue;
 		rcu_read_lock_bh();
-		r = rcu_dereference(rt_hash_table[st->bucket].chain);
+		r = rcu_dereference_bh(rt_hash_table[st->bucket].chain);
 		while (r) {
 			if (dev_net(r->u.dst.dev) == seq_file_net(seq) &&
 			    r->rt_genid == st->genid)
 				return r;
-			r = rcu_dereference(r->u.dst.rt_next);
+			r = rcu_dereference_bh(r->u.dst.rt_next);
 		}
 		rcu_read_unlock_bh();
 	}
@@ -314,7 +314,7 @@ static struct rtable *__rt_cache_get_next(struct seq_file *seq,
 		rcu_read_lock_bh();
 		r = rt_hash_table[st->bucket].chain;
 	}
-	return rcu_dereference(r);
+	return rcu_dereference_bh(r);
 }
 
 static struct rtable *rt_cache_get_next(struct seq_file *seq,
@@ -2687,8 +2687,8 @@ int __ip_route_output_key(struct net *net, struct rtable **rp,
 	hash = rt_hash(flp->fl4_dst, flp->fl4_src, flp->oif, rt_genid(net));
 
 	rcu_read_lock_bh();
-	for (rth = rcu_dereference(rt_hash_table[hash].chain); rth;
-		rth = rcu_dereference(rth->u.dst.rt_next)) {
+	for (rth = rcu_dereference_bh(rt_hash_table[hash].chain); rth;
+		rth = rcu_dereference_bh(rth->u.dst.rt_next)) {
 		if (rth->fl.fl4_dst == flp->fl4_dst &&
 		    rth->fl.fl4_src == flp->fl4_src &&
 		    rth->fl.iif == 0 &&
@@ -3006,8 +3006,8 @@ int ip_rt_dump(struct sk_buff *skb,  struct netlink_callback *cb)
 		if (!rt_hash_table[h].chain)
 			continue;
 		rcu_read_lock_bh();
-		for (rt = rcu_dereference(rt_hash_table[h].chain), idx = 0; rt;
-		     rt = rcu_dereference(rt->u.dst.rt_next), idx++) {
+		for (rt = rcu_dereference_bh(rt_hash_table[h].chain), idx = 0; rt;
+		     rt = rcu_dereference_bh(rt->u.dst.rt_next), idx++) {
 			if (!net_eq(dev_net(rt->u.dst.dev), net) || idx < s_idx)
 				continue;
 			if (rt_is_expired(rt))
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index f126d18..939471e 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -508,7 +508,7 @@ static inline unsigned int run_filter(struct sk_buff *skb, struct sock *sk,
 	struct sk_filter *filter;
 
 	rcu_read_lock_bh();
-	filter = rcu_dereference(sk->sk_filter);
+	filter = rcu_dereference_bh(sk->sk_filter);
 	if (filter != NULL)
 		res = sk_run_filter(skb, filter->insns, filter->len);
 	rcu_read_unlock_bh();
-- 
1.6.6


^ permalink raw reply	[flat|nested] 21+ messages in thread

end of thread, other threads:[~2010-02-25 10:11 UTC | newest]

Thread overview: 21+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2010-01-05  2:03 [PATCH tip/core/rcu 0/8] rcu: add lockdep-based diagnostics to rcu_dereference() Paul E. McKenney
2010-01-05  2:04 ` [PATCH tip/core/rcu 1/8] rcu: introduce lockdep-based checking to RCU read-side primitives Paul E. McKenney
2010-01-13 10:28   ` [tip:core/rcu] rcu: Introduce " tip-bot for Paul E. McKenney
2010-01-05  2:04 ` [PATCH tip/core/rcu 2/8] rcu: add lockdep-enabled variants of rcu_dereference() Paul E. McKenney
2010-01-13 10:28   ` [tip:core/rcu] rcu: Add " tip-bot for Paul E. McKenney
2010-01-05  2:04 ` [PATCH tip/core/rcu 3/8] rcu: disable lockdep checking in RCU list-traversal primitives Paul E. McKenney
2010-01-13 10:29   ` [tip:core/rcu] rcu: Disable " tip-bot for Paul E. McKenney
2010-01-05  2:04 ` [PATCH tip/core/rcu 4/8] net: add checking to rcu_dereference() primitives Paul E. McKenney
2010-01-13 10:30   ` [tip:core/rcu] net: Add " tip-bot for Paul E. McKenney
2010-01-05  2:04 ` [PATCH tip/core/rcu 5/8] sched: use lockdep-based checking on rcu_dereference() Paul E. McKenney
2010-01-13 10:29   ` [tip:core/rcu] sched: Use " tip-bot for Paul E. McKenney
2010-01-05  2:04 ` [PATCH tip/core/rcu 6/8] vfs: apply lockdep-based checking to rcu_dereference() uses Paul E. McKenney
2010-01-13 10:30   ` [tip:core/rcu] vfs: Apply " tip-bot for Paul E. McKenney
2010-01-05  2:04 ` [PATCH tip/core/rcu 7/8] radix-tree: disable RCU lockdep checking in radix tree Paul E. McKenney
2010-01-13 10:29   ` [tip:core/rcu] radix-tree: Disable " tip-bot for Paul E. McKenney
2010-01-05  2:04 ` [PATCH tip/core/rcu 8/8] idr: apply lockdep-based diagnostics to rcu_dereference() uses Paul E. McKenney
2010-01-13 10:29   ` [tip:core/rcu] idr: Apply " tip-bot for Paul E. McKenney
2010-01-13  9:22 ` [PATCH tip/core/rcu 0/8] rcu: add lockdep-based diagnostics to rcu_dereference() Ingo Molnar
2010-01-13 16:17   ` Paul E. McKenney
2010-01-13 16:37     ` Ingo Molnar
2010-02-23  1:04 [PATCH tip/core/rcu 05/21] net: add checking to rcu_dereference() primitives Paul E. McKenney
2010-02-25 10:10 ` [tip:core/rcu] net: Add " tip-bot for Paul E. McKenney

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox

all inboxes | Powered by JetHome®