• Jarek Poplawski's avatar
    ipv4: Suppress lockdep-RCU false positive in FIB trie (3) · f6b085b6
    Jarek Poplawski authored
    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: default avatarJarek Poplawski <jarkao2@gmail.com>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    f6b085b6
fib_trie.c 61.7 KB