next-20080710: possible recursive locking detected at qdisc_lock_tree

Hi

It happens during booting.
It is x86_64 SMP.
[    0.393307] PCI: Using ACPI for IRQ routing
[    0.407715] DMAR:parse DMAR table failure.
[    0.408565] PCI-DMA: Disabling AGP.
[    0.409973] PCI-DMA: aperture base @ 20000000 size 65536 KB
[    0.409973] PCI-DMA: using GART IOMMU.
[    0.409973] PCI-DMA: Reserving 64MB of IOMMU area in the AGP aperture
[    0.420674] system 00:00: iomem range 0xfff00000-0xffffffff could
not be reserved
[    0.420739] system 00:00: iomem range 0xfec00000-0xfec00fff could
not be reserved
[    0.420799] system 00:00: iomem range 0xfee00000-0xfeefffff could
not be reserved
[    0.420860] system 00:00: iomem range 0xf8000000-0xf9ffffff could
not be reserved
[    0.420931] system 00:02: iomem range 0xd0040000-0xd0047fff has been reserved
[    0.420992] system 00:03: ioport range 0x1000-0x107f has been reserved
[    0.421041] system 00:03: ioport range 0x1080-0x10ff has been reserved
[    0.421090] system 00:03: ioport range 0x1400-0x147f has been reserved
[    0.421138] system 00:03: ioport range 0x1480-0x14ff has been reserved
[    0.421187] system 00:03: ioport range 0x1800-0x187f has been reserved
[    0.421235] system 00:03: ioport range 0x1880-0x18ff has been reserved
[    0.421284] system 00:03: ioport range 0x3440-0x347f has been reserved
[    0.421333] system 00:03: ioport range 0x3400-0x343f has been reserved
[    0.421393] system 00:04: ioport range 0x4d0-0x4d1 has been reserved
[    0.421441] system 00:04: ioport range 0xca8-0xca8 has been reserved
[    0.421490] system 00:04: ioport range 0xcac-0xcac has been reserved
[    0.421538] system 00:04: ioport range 0x295-0x296 has been reserved
[    0.426638]
[    0.426638] =============================================
[    0.426638] [ INFO: possible recursive locking detected ]
[    0.426638] 2.6.26-rc9-next-20080710 #5
[    0.426638] ---------------------------------------------
[    0.426638] swapper/1 is trying to acquire lock:
[    0.426638]  (&queue->lock){-...}, at: [<ffffffff8041c3d0>]
qdisc_lock_tree+0x27/0x2c
[    0.426638]

49 more lines

Alexander Beregalov wrote, On 07/10/2008 11:04 AM:
...

[    0.426638] =============================================
[    0.426638] [ INFO: possible recursive locking detected ]
[    0.426638] 2.6.26-rc9-next-20080710 #5
[    0.426638] ---------------------------------------------
[    0.426638] swapper/1 is trying to acquire lock:
[    0.426638]  (&queue->lock){-...}, at: [<ffffffff8041c3d0>]
qdisc_lock_tree+0x27/0x2c
[    0.426638]
[    0.426638] but task is already holding lock:
[    0.426638]  (&queue->lock){-...}, at: [<ffffffff8041c3c8>]
qdisc_lock_tree+0x1f/0x2c
[    0.426638]
[    0.426638] other info that might help us debug this:
[    0.426638] 3 locks held by swapper/1:
[    0.426638]  #0:  (net_mutex){--..}, at: [<ffffffff8040b827>]
register_pernet_device+0x1a/0x5a
[    0.426638]  #1:  (rtnl_mutex){--..}, at: [<ffffffff80417179>]
rtnl_lock+0x12/0x14
[    0.426638]  #2:  (&queue->lock){-...}, at: [<ffffffff8041c3c8>]
qdisc_lock_tree+0x1f/0x2c
[    0.426638]
[    0.426638] stack backtrace:
[    0.426638] Pid: 1, comm: swapper Not tainted 2.6.26-rc9-next-20080710 #5
[    0.426638]
[    0.426638] Call Trace:
[    0.426638]  [<ffffffff8024f95a>] __lock_acquire+0xba9/0xf12
[    0.426638]  [<ffffffff8041c3d0>] ? qdisc_lock_tree+0x27/0x2c
[    0.426638]  [<ffffffff8024fd48>] lock_acquire+0x85/0xa9
[    0.426638]  [<ffffffff8041c3d0>] ? qdisc_lock_tree+0x27/0x2c
[    0.426638]  [<ffffffff80476794>] _spin_lock+0x25/0x31
[    0.426638]  [<ffffffff8041c3d0>] qdisc_lock_tree+0x27/0x2c
[    0.426638]  [<ffffffff8041c412>] dev_init_scheduler+0x11/0x94
[    0.426638]  [<ffffffff8040f3be>] register_netdevice+0x296/0x3f0
[    0.426638]  [<ffffffff8040f552>] register_netdev+0x3a/0x48
[    0.426638]  [<ffffffff805fc274>] loopback_net_init+0x40/0x7a
[    0.426638]  [<ffffffff805fc222>] ? loopback_init+0x0/0x12

...

lockdep needs separate lock init to distinguish rx and tx queue locks.
(There is no real lockup danger.)

Reported-by: Alexander Beregalov <redacted>
Signed-off-by: Jarek Poplawski <redacted>

---

 net/core/dev.c |   20 ++++++++++++++------
 1 files changed, 14 insertions(+), 6 deletions(-)

diff --git a/net/core/dev.c b/net/core/dev.c
index a29a359..157b683 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c

@@ -4090,17 +4090,25 @@ static struct net_device_stats *internal_stats(struct net_device *dev)
 	return &dev->stats;
 }
 
-static void netdev_init_one_queue(struct net_device *dev,
-				  struct netdev_queue *queue)
+static void netdev_init_rx_queue(struct net_device *dev,
+				  struct netdev_queue *rx_queue)
 {
-	spin_lock_init(&queue->lock);
-	queue->dev = dev;
+	spin_lock_init(&rx_queue->lock);
+	rx_queue->dev = dev;
+}
+
+/* lockdep needs separate init to distinguish these locks */
+static void netdev_init_tx_queue(struct net_device *dev,
+				  struct netdev_queue *tx_queue)
+{
+	spin_lock_init(&tx_queue->lock);
+	tx_queue->dev = dev;
 }
 
 static void netdev_init_queues(struct net_device *dev)
 {
-	netdev_init_one_queue(dev, &dev->rx_queue);
-	netdev_init_one_queue(dev, &dev->tx_queue);
+	netdev_init_rx_queue(dev, &dev->rx_queue);
+	netdev_init_tx_queue(dev, &dev->tx_queue);
 }
 
 /**