diff options
| author | Jarek Poplawski <jarkao2@gmail.com> | 2010-09-07 07:51:17 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2010-09-08 14:14:20 -0700 |
| commit | f6b085b69d1cbbd62f49f34e71a3d58cb6d34b7e (patch) | |
| tree | 13d067c1be55a7d87b66ce5920890fcf1f72bcf1 /net/ipv4/fib_trie.c | |
| parent | ee9c5cfad29c8a13199962614b9b16f1c4137ac9 (diff) | |
ipv4: Suppress lockdep-RCU false positive in FIB trie (3)
Hi,
Here is one more of these warnings and a patch below:
Sep 5 23:52:33 del kernel: [46044.244833] ===================================================
Sep 5 23:52:33 del kernel: [46044.269681] [ INFO: suspicious rcu_dereference_check() usage. ]
Sep 5 23:52:33 del kernel: [46044.277000] ---------------------------------------------------
Sep 5 23:52:33 del kernel: [46044.285185] net/ipv4/fib_trie.c:1756 invoked rcu_dereference_check() without protection!
Sep 5 23:52:33 del kernel: [46044.293627]
Sep 5 23:52:33 del kernel: [46044.293632] other info that might help us debug this:
Sep 5 23:52:33 del kernel: [46044.293634]
Sep 5 23:52:33 del kernel: [46044.325333]
Sep 5 23:52:33 del kernel: [46044.325335] rcu_scheduler_active = 1, debug_locks = 0
Sep 5 23:52:33 del kernel: [46044.348013] 1 lock held by pppd/1717:
Sep 5 23:52:33 del kernel: [46044.357548] #0: (rtnl_mutex){+.+.+.}, at: [<c125dc1f>] rtnl_lock+0xf/0x20
Sep 5 23:52:33 del kernel: [46044.367647]
Sep 5 23:52:33 del kernel: [46044.367652] stack backtrace:
Sep 5 23:52:33 del kernel: [46044.387429] Pid: 1717, comm: pppd Not tainted 2.6.35.4.4a #3
Sep 5 23:52:33 del kernel: [46044.398764] Call Trace:
Sep 5 23:52:33 del kernel: [46044.409596] [<c12f9aba>] ? printk+0x18/0x1e
Sep 5 23:52:33 del kernel: [46044.420761] [<c1053969>] lockdep_rcu_dereference+0xa9/0xb0
Sep 5 23:52:33 del kernel: [46044.432229] [<c12b7235>] trie_firstleaf+0x65/0x70
Sep 5 23:52:33 del kernel: [46044.443941] [<c12b74d4>] fib_table_flush+0x14/0x170
Sep 5 23:52:33 del kernel: [46044.455823] [<c1033e92>] ? local_bh_enable_ip+0x62/0xd0
Sep 5 23:52:33 del kernel: [46044.467995] [<c12fc39f>] ? _raw_spin_unlock_bh+0x2f/0x40
Sep 5 23:52:33 del kernel: [46044.480404] [<c12b24d0>] ? fib_sync_down_dev+0x120/0x180
Sep 5 23:52:33 del kernel: [46044.493025] [<c12b069d>] fib_flush+0x2d/0x60
Sep 5 23:52:33 del kernel: [46044.505796] [<c12b06f5>] fib_disable_ip+0x25/0x50
Sep 5 23:52:33 del kernel: [46044.518772] [<c12b10d3>] fib_netdev_event+0x73/0xd0
Sep 5 23:52:33 del kernel: [46044.531918] [<c1048dfd>] notifier_call_chain+0x2d/0x70
Sep 5 23:52:33 del kernel: [46044.545358] [<c1048f0a>] raw_notifier_call_chain+0x1a/0x20
Sep 5 23:52:33 del kernel: [46044.559092] [<c124f687>] call_netdevice_notifiers+0x27/0x60
Sep 5 23:52:33 del kernel: [46044.573037] [<c124faec>] __dev_notify_flags+0x5c/0x80
Sep 5 23:52:33 del kernel: [46044.586489] [<c124fb47>] dev_change_flags+0x37/0x60
Sep 5 23:52:33 del kernel: [46044.599394] [<c12a8a8d>] devinet_ioctl+0x54d/0x630
Sep 5 23:52:33 del kernel: [46044.612277] [<c12aabb7>] inet_ioctl+0x97/0xc0
Sep 5 23:52:34 del kernel: [46044.625208] [<c123f6af>] sock_ioctl+0x6f/0x270
Sep 5 23:52:34 del kernel: [46044.638046] [<c109d2b0>] ? handle_mm_fault+0x420/0x6c0
Sep 5 23:52:34 del kernel: [46044.650968] [<c123f640>] ? sock_ioctl+0x0/0x270
Sep 5 23:52:34 del kernel: [46044.663865] [<c10c3188>] vfs_ioctl+0x28/0xa0
Sep 5 23:52:34 del kernel: [46044.676556] [<c10c38fa>] do_vfs_ioctl+0x6a/0x5c0
Sep 5 23:52:34 del kernel: [46044.688989] [<c1048676>] ? up_read+0x16/0x30
Sep 5 23:52:34 del kernel: [46044.701411] [<c1021376>] ? do_page_fault+0x1d6/0x3a0
Sep 5 23:52:34 del kernel: [46044.714223] [<c10b6588>] ? fget_light+0xf8/0x2f0
Sep 5 23:52:34 del kernel: [46044.726601] [<c1241f98>] ? sys_socketcall+0x208/0x2c0
Sep 5 23:52:34 del kernel: [46044.739140] [<c10c3eb3>] sys_ioctl+0x63/0x70
Sep 5 23:52:34 del kernel: [46044.751967] [<c12fca3d>] syscall_call+0x7/0xb
Sep 5 23:52:34 del kernel: [46044.764734] [<c12f0000>] ? cookie_v6_check+0x3d0/0x630
-------------->
This patch fixes the warning:
===================================================
[ INFO: suspicious rcu_dereference_check() usage. ]
---------------------------------------------------
net/ipv4/fib_trie.c:1756 invoked rcu_dereference_check() without protection!
other info that might help us debug this:
rcu_scheduler_active = 1, debug_locks = 0
1 lock held by pppd/1717:
#0: (rtnl_mutex){+.+.+.}, at: [<c125dc1f>] rtnl_lock+0xf/0x20
stack backtrace:
Pid: 1717, comm: pppd Not tainted 2.6.35.4a #3
Call Trace:
[<c12f9aba>] ? printk+0x18/0x1e
[<c1053969>] lockdep_rcu_dereference+0xa9/0xb0
[<c12b7235>] trie_firstleaf+0x65/0x70
[<c12b74d4>] fib_table_flush+0x14/0x170
...
Allow trie_firstleaf() to be called either under rcu_read_lock()
protection or with RTNL held. The same annotation is added to
node_parent_rcu() to prevent a similar warning a bit later.
Followup of commits 634a4b20 and 4eaa0e3c.
Signed-off-by: Jarek Poplawski <jarkao2@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/fib_trie.c')
| -rw-r--r-- | net/ipv4/fib_trie.c | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/net/ipv4/fib_trie.c b/net/ipv4/fib_trie.c index 79d057a939ba..4a8e370862bc 100644 --- a/net/ipv4/fib_trie.c +++ b/net/ipv4/fib_trie.c @@ -186,7 +186,9 @@ static inline struct tnode *node_parent_rcu(struct node *node) { struct tnode *ret = node_parent(node); - return rcu_dereference(ret); + return rcu_dereference_check(ret, + rcu_read_lock_held() || + lockdep_rtnl_is_held()); } /* Same as rcu_assign_pointer @@ -1753,7 +1755,9 @@ static struct leaf *leaf_walk_rcu(struct tnode *p, struct node *c) static struct leaf *trie_firstleaf(struct trie *t) { - struct tnode *n = (struct tnode *) rcu_dereference(t->trie); + struct tnode *n = (struct tnode *) rcu_dereference_check(t->trie, + rcu_read_lock_held() || + lockdep_rtnl_is_held()); if (!n) return NULL; |