Getting the following splat with ping in a VRF:
[ 49.036323] ======================================================
[ 49.038300] [ INFO: possible circular locking dependency detected ]
[ 49.040313] 4.7.0-rc1+ #252 Not tainted
[ 49.041502] -------------------------------------------------------
[ 49.043518] ping/2143 is trying to acquire lock:
[ 49.044999] (&(&list->lock)->rlock#3){+.-...}, at: [<ffffffff81407cc5>]
__dev_queue_xmit+0x3d3/0x751
[ 49.048107]
[ 49.048107] but task is already holding lock:
[ 49.049844] (dev->qdisc_running_key ?: &qdisc_running_key){+.-...}, at:
[<ffffffff81407d1a>] __dev_queue_xmit+0x428/0x751
[ 49.052783]
[ 49.052783] which lock already depends on the new lock.
[ 49.052783]
[ 49.054455]
[ 49.054455] the existing dependency chain (in reverse order) is:
[ 49.055894]
-> #1 (dev->qdisc_running_key ?: &qdisc_running_key){+.-...}:
[ 49.057531] [<ffffffff810853b7>] __lock_acquire+0x5e4/0x690
[ 49.058924] [<ffffffff81085a32>] lock_acquire+0x140/0x1d8
[ 49.060271] [<ffffffff81401fe6>] write_seqcount_begin+0x21/0x24
[ 49.061741] [<ffffffff81407d1a>] __dev_queue_xmit+0x428/0x751
[ 49.062936] [<ffffffff8140804e>] dev_queue_xmit+0xb/0xd
[ 49.064258] [<ffffffff81411989>] neigh_resolve_output+0x113/0x12e
[ 49.065767] [<ffffffff8149fda9>] ip6_finish_output2+0x39b/0x3ee
[ 49.067212] [<ffffffff814a2472>] ip6_finish_output+0x96/0x9d
[ 49.068568] [<ffffffff814a24f9>] ip6_output+0x80/0xe9
[ 49.069789] [<ffffffff814bf9bc>] dst_output+0x4f/0x56
[ 49.070824] [<ffffffff814c01b6>] mld_sendpack+0x17e/0x1fd
[ 49.071964] [<ffffffff814c17d9>] mld_ifc_timer_expire+0x1ea/0x21e
[ 49.073407] [<ffffffff8109deb9>] call_timer_fn+0x120/0x303
[ 49.074551] [<ffffffff8109e29b>] run_timer_softirq+0x1ae/0x1d8
[ 49.075399] [<ffffffff8105129a>] __do_softirq+0x1c3/0x451
[ 49.076217] [<ffffffff81051744>] irq_exit+0x40/0x94
[ 49.076945] [<ffffffff81031069>] smp_apic_timer_interrupt+0x29/0x34
[ 49.077849] [<ffffffff814f6fac>] apic_timer_interrupt+0x8c/0xa0
[ 49.078719] [<ffffffff8101da2d>] default_idle+0x1f/0x32
[ 49.079462] [<ffffffff8101dfe0>] arch_cpu_idle+0xa/0xc
[ 49.080191] [<ffffffff8107eeca>] default_idle_call+0x1e/0x20
[ 49.080989] [<ffffffff8107f002>] cpu_startup_entry+0x136/0x1ee
[ 49.081805] [<ffffffff814f05b4>] rest_init+0x12b/0x131
[ 49.082551] [<ffffffff81cb8ea2>] start_kernel+0x3da/0x3e7
[ 49.083317] [<ffffffff81cb841b>] x86_64_start_reservations+0x2f/0x31
[ 49.084192] [<ffffffff81cb854a>] x86_64_start_kernel+0x12d/0x13a
[ 49.085025]
-> #0 (&(&list->lock)->rlock#3){+.-...}:
[ 49.085749] [<ffffffff8108435a>] validate_chain.isra.37+0x7c8/0xa5b
[ 49.086631] [<ffffffff810853b7>] __lock_acquire+0x5e4/0x690
[ 49.087427] [<ffffffff81085a32>] lock_acquire+0x140/0x1d8
[ 49.088194] [<ffffffff814f5896>] _raw_spin_lock+0x2f/0x65
[ 49.088961] [<ffffffff81407cc5>] __dev_queue_xmit+0x3d3/0x751
[ 49.089771] [<ffffffff8140804e>] dev_queue_xmit+0xb/0xd
[ 49.090534] [<ffffffff8146a633>] arp_xmit+0x32/0x7e
[ 49.091238] [<ffffffff8146a6bb>] arp_send_dst+0x3c/0x42
[ 49.091972] [<ffffffff8146a93c>] arp_solicit+0x27b/0x28e
[ 49.092719] [<ffffffff8140ead8>] neigh_probe+0x4a/0x5e
[ 49.093448] [<ffffffff814100b8>] __neigh_event_send+0x1d0/0x21b
[ 49.094305] [<ffffffff8141012e>] neigh_event_send+0x2b/0x2d
[ 49.095080] [<ffffffff8141188e>] neigh_resolve_output+0x18/0x12e
[ 49.095908] [<ffffffff81441bf2>] ip_finish_output2+0x3c0/0x41c
[ 49.096716] [<ffffffff81442485>] ip_finish_output+0x132/0x13e
[ 49.097517] [<ffffffff814424b2>] NF_HOOK_COND.constprop.43+0x21/0x8a
[ 49.098408] [<ffffffff81443623>] ip_output+0x65/0x6a
[ 49.099131] [<ffffffff814414ed>] dst_output+0x2b/0x30
[ 49.099848] [<ffffffff81442f64>] ip_local_out+0x2a/0x31
[ 49.100580] [<ffffffff81398201>] vrf_xmit+0x149/0x28c
[ 49.101294] [<ffffffff814075f1>] dev_hard_start_xmit+0x154/0x337
[ 49.102169] [<ffffffff8142795e>] sch_direct_xmit+0x98/0x16c
[ 49.102948] [<ffffffff81407d45>] __dev_queue_xmit+0x453/0x751
[ 49.103747] [<ffffffff8140804e>] dev_queue_xmit+0xb/0xd
[ 49.104480] [<ffffffff81411989>] neigh_resolve_output+0x113/0x12e
[ 49.105322] [<ffffffff813976aa>] dst_neigh_output.isra.18+0x13b/0x148
[ 49.106204] [<ffffffff813977bb>] vrf_finish_output+0x104/0x139
[ 49.107044] [<ffffffff81397986>] vrf_output+0x5c/0xc1
[ 49.107755] [<ffffffff814414ed>] dst_output+0x2b/0x30
[ 49.108472] [<ffffffff81442f64>] ip_local_out+0x2a/0x31
[ 49.109211] [<ffffffff81443dd5>] ip_send_skb+0x14/0x38
[ 49.109941] [<ffffffff81443e27>] ip_push_pending_frames+0x2e/0x31
[ 49.110792] [<ffffffff81464a77>] raw_sendmsg+0x788/0x9d2
[ 49.111543] [<ffffffff81471de5>] inet_sendmsg+0x35/0x5c
[ 49.112283] [<ffffffff813ece43>] sock_sendmsg_nosec+0x12/0x1d
[ 49.113079] [<ffffffff813edcf7>] ___sys_sendmsg+0x1b1/0x21f
[ 49.113851] [<ffffffff813ee01c>] __sys_sendmsg+0x40/0x5e
[ 49.114609] [<ffffffff813ee04e>] SyS_sendmsg+0x14/0x16
[ 49.115345] [<ffffffff814f633c>] entry_SYSCALL_64_fastpath+0x1f/0xbd
[ 49.116221]
[ 49.116221] other info that might help us debug this:
[ 49.116221]
[ 49.117198] Possible unsafe locking scenario:
[ 49.117198]
[ 49.117926] CPU0 CPU1
[ 49.118503] ---- ----
[ 49.119059] lock(dev->qdisc_running_key ?: &qdisc_running_key);
[ 49.119839] lock(&(&list->lock)->rlock#3);
[ 49.120722] lock(dev->qdisc_running_key ?: &qdisc_running_key);
[ 49.121800] lock(&(&list->lock)->rlock#3);
[ 49.122396]
[ 49.122396] *** DEADLOCK ***
[ 49.122396]
[ 49.123134] 6 locks held by ping/2143:
[ 49.123604] #0: (sk_lock-AF_INET){+.+.+.}, at: [<ffffffff81464a18>]
raw_sendmsg+0x729/0x9d2
[ 49.124749] #1: (rcu_read_lock_bh){......}, at: [<ffffffff81397076>]
rcu_lock_acquire+0x0/0x20
[ 49.125914] #2: (rcu_read_lock_bh){......}, at: [<ffffffff813ff64d>]
rcu_lock_acquire+0x0/0x20
[ 49.127103] #3: (dev->qdisc_running_key ?: &qdisc_running_key){+.-...},
at: [<ffffffff81407d1a>] __dev_queue_xmit+0x428/0x751
[ 49.128592] #4: (rcu_read_lock_bh){......}, at: [<ffffffff814412dd>]
rcu_lock_acquire+0x0/0x20
[ 49.129760] #5: (rcu_read_lock_bh){......}, at: [<ffffffff813ff64d>]
rcu_lock_acquire+0x0/0x20
[ 49.130940]
git bisect points to:
$ git bisect good
f9eb8aea2a1e12fc2f584d1627deeb957435a801 is the first bad commit
commit f9eb8aea2a1e12fc2f584d1627deeb957435a801
Author: Eric Dumazet <eduma...@google.com>
Date: Mon Jun 6 09:37:15 2016 -0700
net_sched: transform qdisc running bit into a seqcount
Instead of using a single bit (__QDISC___STATE_RUNNING)
in sch->__state, use a seqcount.
This adds lockdep support, but more importantly it will allow us
to sample qdisc/class statistics without having to grab qdisc root lock.
Fix by adding the IFF_NO_QUEUE flag for VRF devices.
Fixes: f9eb8aea2a1e ("net_sched: transform qdisc running bit into a seqcount")
Signed-off-by: David Ahern <d...@cumulusnetworks.com>
---
drivers/net/vrf.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/net/vrf.c b/drivers/net/vrf.c
index e3e693bf0dec..a3da975cd2df 100644
--- a/drivers/net/vrf.c
+++ b/drivers/net/vrf.c
@@ -999,6 +999,8 @@ static void vrf_setup(struct net_device *dev)
/* Fill in device structure with ethernet-generic values. */
eth_hw_addr_random(dev);
+ dev->priv_flags |= IFF_NO_QUEUE;
+
/* don't acquire vrf device's netif_tx_lock when transmitting */
dev->features |= NETIF_F_LLTX;
--
2.1.4
