I reported one of the duplicates that you've merged. I still see this warning running 2.6.31-19-server (x86_64).
I have a feeling this is related, in my case, to bittorrent traffic. This box is a NAS and SAN serving several diskless boxes over iSCSI, NFS and CIFS, and its gigabit NIC sees a LOT of traffic all the time. However I hadn't seen this warning for over a month. Last week I downloaded and seeded at decent speeds (10-20Mbps) several distro DVDs, and I got three of these warnings in three days, all implicating the 100Mbps NIC. It's all circumstantial, but could be a clue as to the root cause.
Feb 22 19:15:44 nas kernel: [ 9062.040017] ------------[ cut here ]------------
Feb 22 19:15:44 nas kernel: [ 9062.040027] WARNING: at /build/buildd/linux-2.6.31/net/sched/sch_generic.c:246 dev_watchdog+0x262/0x270()
Feb 22 19:15:44 nas kernel: [ 9062.040030] Hardware name: GA-MA770-US3
Feb 22 19:15:44 nas kernel: [ 9062.040032] NETDEV WATCHDOG: eth1 (8139too): transmit queue 0 timed out
Feb 22 19:15:44 nas kernel: [ 9062.040034] Modules linked in: binfmt_misc ppdev iscsi_trgt crc32c ib_iser rdma_cm ib_cm iw_cm ib_sa ib_mad ib_core ib_addr iscsi_tcp nfsd libiscsi_tcp libiscsi scsi_transport_iscsi nfs lockd nfs_acl auth_rpcgss sunrpc iptable_filter ip_tables x_tables i2c_piix4 serio_raw lp amd64_edac_mod edac_core k8temp parport xfs exportfs raid10 raid456 raid6_pq async_xor async_memcpy async_tx xor raid1 raid0 multipath 8139too 8139cp linear r8169 mii
Feb 22 19:15:44 nas kernel: [ 9062.040066] Pid: 0, comm: swapper Not tainted 2.6.31-19-server #56-Ubuntu
Feb 22 19:15:44 nas kernel: [ 9062.040068] Call Trace:
Feb 22 19:15:44 nas kernel: [ 9062.040070] <IRQ> [<ffffffff8105e508>] warn_slowpath_common+0x78/0xb0
Feb 22 19:15:44 nas kernel: [ 9062.040079] [<ffffffff8105e59c>] warn_slowpath_fmt+0x3c/0x40
Feb 22 19:15:44 nas kernel: [ 9062.040082] [<ffffffff8144e322>] dev_watchdog+0x262/0x270
Feb 22 19:15:44 nas kernel: [ 9062.040086] [<ffffffff8107c471>] ? ktime_get_ts+0x51/0x70
Feb 22 19:15:44 nas kernel: [ 9062.040090] [<ffffffff8103435f>] ? hpet_msi_next_event+0xf/0x20
Feb 22 19:15:44 nas kernel: [ 9062.040094] [<ffffffff8108506f>] ? clockevents_program_event+0x4f/0x90
Feb 22 19:15:44 nas kernel: [ 9062.040097] [<ffffffff81086560>] ? tick_dev_program_event+0x40/0xd0
Feb 22 19:15:44 nas kernel: [ 9062.040100] [<ffffffff8144e0c0>] ? dev_watchdog+0x0/0x270
Feb 22 19:15:44 nas kernel: [ 9062.040103] [<ffffffff8106a7fc>] run_timer_softirq+0x16c/0x270
Feb 22 19:15:44 nas kernel: [ 9062.040107] [<ffffffff810650ed>] __do_softirq+0xbd/0x200
Feb 22 19:15:44 nas kernel: [ 9062.040111] [<ffffffff810131ac>] call_softirq+0x1c/0x30
Feb 22 19:15:44 nas kernel: [ 9062.040113] [<ffffffff81014b85>] do_softirq+0x55/0x90
Feb 22 19:15:44 nas kernel: [ 9062.040116] [<ffffffff81064e55>] irq_exit+0x85/0x90
Feb 22 19:15:44 nas kernel: [ 9062.040119] [<ffffffff810140c0>] do_IRQ+0x70/0xe0
Feb 22 19:15:44 nas kernel: [ 9062.040123] [<ffffffff810129d3>] ret_from_intr+0x0/0x11
Feb 22 19:15:44 nas kernel: [ 9062.040124] <EOI> [<ffffffff810356f6>] ? native_safe_halt+0x6/0x10
Feb 22 19:15:44 nas kernel: [ 9062.040130] [<ffffffff8101a0fc>] ? default_idle+0x4c/0xe0
Feb 22 19:15:44 nas kernel: [ 9062.040133] [<ffffffff8101a1ee>] ? c1e_idle+0x5e/0x120
Feb 22 19:15:44 nas kernel: [ 9062.040137] [<ffffffff81010e02>] ? cpu_idle+0xb2/0x100
Feb 22 19:15:44 nas kernel: [ 9062.040140] [<ffffffff81512c36>] ? rest_init+0x66/0x70
Feb 22 19:15:44 nas kernel: [ 9062.040144] [<ffffffff81838047>] ? start_kernel+0x352/0x35b
Feb 22 19:15:44 nas kernel: [ 9062.040148] [<ffffffff8183759a>] ? x86_64_start_reservations+0x125/0x129
Feb 22 19:15:44 nas kernel: [ 9062.040151] [<ffffffff81837698>] ? x86_64_start_kernel+0xfa/0x109
Feb 22 19:15:44 nas kernel: [ 9062.040153] ---[ end trace 58f80f6497633a24 ]---
I reported one of the duplicates that you've merged. I still see this warning running 2.6.31-19-server (x86_64).
I have a feeling this is related, in my case, to bittorrent traffic. This box is a NAS and SAN serving several diskless boxes over iSCSI, NFS and CIFS, and its gigabit NIC sees a LOT of traffic all the time. However I hadn't seen this warning for over a month. Last week I downloaded and seeded at decent speeds (10-20Mbps) several distro DVDs, and I got three of these warnings in three days, all implicating the 100Mbps NIC. It's all circumstantial, but could be a clue as to the root cause.
Feb 22 19:15:44 nas kernel: [ 9062.040017] ------------[ cut here ]------------ buildd/ linux-2. 6.31/net/ sched/sch_ generic. c:246 dev_watchdog+ 0x262/0x270( ) iscsi nfs lockd nfs_acl auth_rpcgss sunrpc iptable_filter ip_tables x_tables i2c_piix4 serio_raw lp amd64_edac_mod edac_core k8temp parport xfs exportfs raid10 raid456 raid6_pq async_xor async_memcpy async_tx xor raid1 raid0 multipath 8139too 8139cp linear r8169 mii 508>] warn_slowpath_ common+ 0x78/0xb0 59c>] warn_slowpath_ fmt+0x3c/ 0x40 322>] dev_watchdog+ 0x262/0x270 471>] ? ktime_get_ ts+0x51/ 0x70 35f>] ? hpet_msi_ next_event+ 0xf/0x20 06f>] ? clockevents_ program_ event+0x4f/ 0x90 560>] ? tick_dev_ program_ event+0x40/ 0xd0 0c0>] ? dev_watchdog+ 0x0/0x270 7fc>] run_timer_ softirq+ 0x16c/0x270 0ed>] __do_softirq+ 0xbd/0x200 1ac>] call_softirq+ 0x1c/0x30 b85>] do_softirq+ 0x55/0x90 e55>] irq_exit+0x85/0x90 0c0>] do_IRQ+0x70/0xe0 9d3>] ret_from_ intr+0x0/ 0x11 6f6>] ? native_ safe_halt+ 0x6/0x10 0fc>] ? default_ idle+0x4c/ 0xe0 1ee>] ? c1e_idle+0x5e/0x120 e02>] ? cpu_idle+0xb2/0x100 c36>] ? rest_init+0x66/0x70 047>] ? start_kernel+ 0x352/0x35b 59a>] ? x86_64_ start_reservati ons+0x125/ 0x129 698>] ? x86_64_ start_kernel+ 0xfa/0x109
Feb 22 19:15:44 nas kernel: [ 9062.040027] WARNING: at /build/
Feb 22 19:15:44 nas kernel: [ 9062.040030] Hardware name: GA-MA770-US3
Feb 22 19:15:44 nas kernel: [ 9062.040032] NETDEV WATCHDOG: eth1 (8139too): transmit queue 0 timed out
Feb 22 19:15:44 nas kernel: [ 9062.040034] Modules linked in: binfmt_misc ppdev iscsi_trgt crc32c ib_iser rdma_cm ib_cm iw_cm ib_sa ib_mad ib_core ib_addr iscsi_tcp nfsd libiscsi_tcp libiscsi scsi_transport_
Feb 22 19:15:44 nas kernel: [ 9062.040066] Pid: 0, comm: swapper Not tainted 2.6.31-19-server #56-Ubuntu
Feb 22 19:15:44 nas kernel: [ 9062.040068] Call Trace:
Feb 22 19:15:44 nas kernel: [ 9062.040070] <IRQ> [<ffffffff8105e
Feb 22 19:15:44 nas kernel: [ 9062.040079] [<ffffffff8105e
Feb 22 19:15:44 nas kernel: [ 9062.040082] [<ffffffff8144e
Feb 22 19:15:44 nas kernel: [ 9062.040086] [<ffffffff8107c
Feb 22 19:15:44 nas kernel: [ 9062.040090] [<ffffffff81034
Feb 22 19:15:44 nas kernel: [ 9062.040094] [<ffffffff81085
Feb 22 19:15:44 nas kernel: [ 9062.040097] [<ffffffff81086
Feb 22 19:15:44 nas kernel: [ 9062.040100] [<ffffffff8144e
Feb 22 19:15:44 nas kernel: [ 9062.040103] [<ffffffff8106a
Feb 22 19:15:44 nas kernel: [ 9062.040107] [<ffffffff81065
Feb 22 19:15:44 nas kernel: [ 9062.040111] [<ffffffff81013
Feb 22 19:15:44 nas kernel: [ 9062.040113] [<ffffffff81014
Feb 22 19:15:44 nas kernel: [ 9062.040116] [<ffffffff81064
Feb 22 19:15:44 nas kernel: [ 9062.040119] [<ffffffff81014
Feb 22 19:15:44 nas kernel: [ 9062.040123] [<ffffffff81012
Feb 22 19:15:44 nas kernel: [ 9062.040124] <EOI> [<ffffffff81035
Feb 22 19:15:44 nas kernel: [ 9062.040130] [<ffffffff8101a
Feb 22 19:15:44 nas kernel: [ 9062.040133] [<ffffffff8101a
Feb 22 19:15:44 nas kernel: [ 9062.040137] [<ffffffff81010
Feb 22 19:15:44 nas kernel: [ 9062.040140] [<ffffffff81512
Feb 22 19:15:44 nas kernel: [ 9062.040144] [<ffffffff81838
Feb 22 19:15:44 nas kernel: [ 9062.040148] [<ffffffff81837
Feb 22 19:15:44 nas kernel: [ 9062.040151] [<ffffffff81837
Feb 22 19:15:44 nas kernel: [ 9062.040153] ---[ end trace 58f80f6497633a24 ]---