cxgb4: Not need to hold the adap_rcu_lock lock when read adap_rcu_list
cxgb4_netdev maybe lead to dead lock, since it uses a spin lock, and be called
in both thread and softirq context, but not disable BH, the lockdep report is
below; In fact, cxgb4_netdev only reads adap_rcu_list with RCU protection, so
not need to hold spin lock again.
=================================
[ INFO: inconsistent lock state ]
3.14.7+ #24 Tainted: G C O
---------------------------------
inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage.
radvd/3794 [HC0[0]:SC1[1]:HE1:SE0] takes:
(adap_rcu_lock){+.?...}, at: [<ffffffffa09989ea>] clip_add+0x2c/0x116 [cxgb4]
{SOFTIRQ-ON-W} state was registered at:
[<ffffffff810fca81>] __lock_acquire+0x34a/0xe48
[<ffffffff810fd98b>] lock_acquire+0x82/0x9d
[<ffffffff815d6ff8>] _raw_spin_lock+0x34/0x43
[<ffffffffa09989ea>] clip_add+0x2c/0x116 [cxgb4]
[<ffffffffa0998beb>] cxgb4_inet6addr_handler+0x117/0x12c [cxgb4]
[<ffffffff815da98b>] notifier_call_chain+0x32/0x5c
[<ffffffff815da9f9>] __atomic_notifier_call_chain+0x44/0x6e
[<ffffffff815daa32>] atomic_notifier_call_chain+0xf/0x11
[<ffffffff815b1356>] inet6addr_notifier_call_chain+0x16/0x18
[<ffffffffa01f72e5>] ipv6_add_addr+0x404/0x46e [ipv6]
[<ffffffffa01f8df0>] addrconf_add_linklocal+0x5f/0x95 [ipv6]
[<ffffffffa01fc3e9>] addrconf_notify+0x632/0x841 [ipv6]
[<ffffffff815da98b>] notifier_call_chain+0x32/0x5c
[<ffffffff810e09a1>] __raw_notifier_call_chain+0x9/0xb
[<ffffffff810e09b2>] raw_notifier_call_chain+0xf/0x11
[<ffffffff8151b3b7>] call_netdevice_notifiers_info+0x4e/0x56
[<ffffffff8151b3d0>] call_netdevice_notifiers+0x11/0x13
[<ffffffff8151c0a6>] netdev_state_change+0x1f/0x38
[<ffffffff8152f004>] linkwatch_do_dev+0x3b/0x49
[<ffffffff8152f184>] __linkwatch_run_queue+0x10b/0x144
[<ffffffff8152f1dd>] linkwatch_event+0x20/0x27
[<ffffffff810d7bc0>] process_one_work+0x1cb/0x2ee
[<ffffffff810d7e3b>] worker_thread+0x12e/0x1fc
[<ffffffff810dd391>] kthread+0xc4/0xcc
[<ffffffff815dc48c>] ret_from_fork+0x7c/0xb0
irq event stamp: 3388
hardirqs last enabled at (3388): [<ffffffff810c6c85>]
__local_bh_enable_ip+0xaa/0xd9
hardirqs last disabled at (3387): [<ffffffff810c6c2d>]
__local_bh_enable_ip+0x52/0xd9
softirqs last enabled at (3288): [<ffffffffa01f1d5b>]
rcu_read_unlock_bh+0x0/0x2f [ipv6]
softirqs last disabled at (3289): [<ffffffff815ddafc>]
do_softirq_own_stack+0x1c/0x30
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0
----
lock(adap_rcu_lock);
<Interrupt>
lock(adap_rcu_lock);
*** DEADLOCK ***
5 locks held by radvd/3794:
#0: (sk_lock-AF_INET6){+.+.+.}, at: [<ffffffffa020b85a>]
rawv6_sendmsg+0x74b/0xa4d [ipv6]
#1: (rcu_read_lock){.+.+..}, at: [<ffffffff8151ac6b>]
rcu_lock_acquire+0x0/0x29
#2: (rcu_read_lock){.+.+..}, at: [<ffffffffa01f4cca>]
rcu_lock_acquire.constprop.16+0x0/0x30 [ipv6]
#3: (rcu_read_lock){.+.+..}, at: [<ffffffff810e09b4>]
rcu_lock_acquire+0x0/0x29
#4: (rcu_read_lock){.+.+..}, at: [<ffffffffa0998782>]
rcu_lock_acquire.constprop.40+0x0/0x30 [cxgb4]
stack backtrace:
CPU: 7 PID: 3794 Comm: radvd Tainted: G C O 3.14.7+ #24
Hardware name: Supermicro X7DBU/X7DBU, BIOS 6.00 12/03/2007
ffffffff81f15990 ffff88012fdc36a8 ffffffff815d0016 0000000000000006
ffff8800c80dc2a0 ffff88012fdc3708 ffffffff815cc727 0000000000000001
0000000000000001 ffff880100000000 ffffffff81015b02 ffff8800c80dcb58
Call Trace:
<IRQ> [<ffffffff815d0016>] dump_stack+0x4e/0x71
[<ffffffff815cc727>] print_usage_bug+0x1ec/0x1fd
[<ffffffff81015b02>] ? save_stack_trace+0x27/0x44
[<ffffffff810fbfaa>] ? check_usage_backwards+0xa0/0xa0
[<ffffffff810fc640>] mark_lock+0x11b/0x212
[<ffffffff810fca0b>] __lock_acquire+0x2d4/0xe48
[<ffffffff810fbfaa>] ? check_usage_backwards+0xa0/0xa0
[<ffffffff810fbff6>] ? check_usage_forwards+0x4c/0xa6
[<ffffffff810c6c8a>] ? __local_bh_enable_ip+0xaf/0xd9
[<ffffffff810fd98b>] lock_acquire+0x82/0x9d
[<ffffffffa09989ea>] ? clip_add+0x2c/0x116 [cxgb4]
[<ffffffffa0998782>] ? rcu_read_unlock+0x23/0x23 [cxgb4]
[<ffffffff815d6ff8>] _raw_spin_lock+0x34/0x43
[<ffffffffa09989ea>] ? clip_add+0x2c/0x116 [cxgb4]
[<ffffffffa09987b0>] ? rcu_lock_acquire.constprop.40+0x2e/0x30 [cxgb4]
[<ffffffffa0998782>] ? rcu_read_unlock+0x23/0x23 [cxgb4]
[<ffffffffa09989ea>] clip_add+0x2c/0x116 [cxgb4]
[<ffffffffa0998beb>] cxgb4_inet6addr_handler+0x117/0x12c [cxgb4]
[<ffffffff810fd99d>] ? lock_acquire+0x94/0x9d
[<ffffffff810e09b4>] ? raw_notifier_call_chain+0x11/0x11
[<ffffffff815da98b>] notifier_call_chain+0x32/0x5c
[<ffffffff815da9f9>] __atomic_notifier_call_chain+0x44/0x6e
[<ffffffff815daa32>] atomic_notifier_call_chain+0xf/0x11
[<ffffffff815b1356>] inet6addr_notifier_call_chain+0x16/0x18
[<ffffffffa01f72e5>] ipv6_add_addr+0x404/0x46e [ipv6]
[<ffffffff810fde6a>] ? trace_hardirqs_on+0xd/0xf
[<ffffffffa01fb634>] addrconf_prefix_rcv+0x385/0x6ea [ipv6]
[<ffffffffa0207950>] ndisc_rcv+0x9d3/0xd76 [ipv6]
[<ffffffffa020d536>] icmpv6_rcv+0x592/0x67b [ipv6]
[<ffffffff810c6c85>] ? __local_bh_enable_ip+0xaa/0xd9
[<ffffffff810c6c85>] ? __local_bh_enable_ip+0xaa/0xd9
[<ffffffff810fd8dc>] ? lock_release+0x14e/0x17b
[<ffffffffa020df97>] ? rcu_read_unlock+0x21/0x23 [ipv6]
[<ffffffff8150df52>] ? rcu_read_unlock+0x23/0x23
[<ffffffffa01f4ede>] ip6_input_finish+0x1e4/0x2fc [ipv6]
[<ffffffffa01f540b>] ip6_input+0x33/0x38 [ipv6]
[<ffffffffa01f5557>] ip6_mc_input+0x147/0x160 [ipv6]
[<ffffffffa01f4ba3>] ip6_rcv_finish+0x7c/0x81 [ipv6]
[<ffffffffa01f5397>] ipv6_rcv+0x3a1/0x3e2 [ipv6]
[<ffffffff8151ef96>] __netif_receive_skb_core+0x4ab/0x511
[<ffffffff810fdc94>] ? mark_held_locks+0x71/0x99
[<ffffffff8151f0c0>] ? process_backlog+0x69/0x15e
[<ffffffff8151f045>] __netif_receive_skb+0x49/0x5b
[<ffffffff8151f0cf>] process_backlog+0x78/0x15e
[<ffffffff8151f571>] ? net_rx_action+0x1a2/0x1cc
[<ffffffff8151f47b>] net_rx_action+0xac/0x1cc
[<ffffffff810c69b7>] ? __do_softirq+0xad/0x218
[<ffffffff810c69ff>] __do_softirq+0xf5/0x218
[<ffffffff815ddafc>] do_softirq_own_stack+0x1c/0x30
<EOI> [<ffffffff810c6bb6>] do_softirq+0x38/0x5d
[<ffffffffa01f1d5b>] ? ip6_copy_metadata+0x156/0x156 [ipv6]
[<ffffffff810c6c78>] __local_bh_enable_ip+0x9d/0xd9
[<ffffffffa01f1d88>] rcu_read_unlock_bh+0x2d/0x2f [ipv6]
[<ffffffffa01f28b4>] ip6_finish_output2+0x381/0x3d8 [ipv6]
[<ffffffffa01f49ef>] ip6_finish_output+0x6e/0x73 [ipv6]
[<ffffffffa01f4a70>] ip6_output+0x7c/0xa8 [ipv6]
[<ffffffff815b1bfa>] dst_output+0x18/0x1c
[<ffffffff815b1c9e>] ip6_local_out+0x1c/0x21
[<ffffffffa01f2489>] ip6_push_pending_frames+0x37d/0x427 [ipv6]
[<ffffffff81558af8>] ? skb_orphan+0x39/0x39
[<ffffffffa020b85a>] ? rawv6_sendmsg+0x74b/0xa4d [ipv6]
[<ffffffffa020ba51>] rawv6_sendmsg+0x942/0xa4d [ipv6]
[<ffffffff81584cd2>] inet_sendmsg+0x3d/0x66
[<ffffffff81508930>] __sock_sendmsg_nosec+0x25/0x27
[<ffffffff8150b0d7>] sock_sendmsg+0x5a/0x7b
[<ffffffff810fd8dc>] ? lock_release+0x14e/0x17b
[<ffffffff8116d756>] ? might_fault+0x9e/0xa5
[<ffffffff8116d70d>] ? might_fault+0x55/0xa5
[<ffffffff81508cb1>] ? copy_from_user+0x2a/0x2c
[<ffffffff8150b70c>] ___sys_sendmsg+0x226/0x2d9
[<ffffffff810fcd25>] ? __lock_acquire+0x5ee/0xe48
[<ffffffff810fde01>] ? trace_hardirqs_on_caller+0x145/0x1a1
[<ffffffff8118efcb>] ? slab_free_hook.isra.71+0x50/0x59
[<ffffffff8115c81f>] ? release_pages+0xbc/0x181
[<ffffffff810fd99d>] ? lock_acquire+0x94/0x9d
[<ffffffff81115e97>] ? read_seqcount_begin.constprop.25+0x73/0x90
[<ffffffff8150c408>] __sys_sendmsg+0x3d/0x5b
[<ffffffff8150c433>] SyS_sendmsg+0xd/0x19
[<ffffffff815dc53d>] system_call_fastpath+0x1a/0x1f
Reported-by: NBen Greear <greearb@candelatech.com>
Cc: Casey Leedom <leedom@chelsio.com>
Cc: Hariprasad Shenai <hariprasad@chelsio.com>
Signed-off-by: NLi RongQing <roy.qing.li@gmail.com>
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Acked-by: NCasey Leedom <leedom@chelsio.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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