Jul 04 11:17:34 frodo kernel: igb 0000:07:00.0: Detected Tx Unit Hang
                                Tx Queue             <3>
                                TDH                  <b2>
                                TDT                  <ce>
                                next_to_use          <ce>
                                next_to_clean        <af>
                              buffer_info[next_to_clean]
                                time_stamp           <10012d342>
                                next_to_watch        <ffff8800c8d6fb30>
                                jiffies              <10012d614>
                                desc.status          <0>
Jul 04 11:17:36 frodo kernel: igb 0000:07:00.0: Detected Tx Unit Hang
                                Tx Queue             <3>
                                TDH                  <b2>
                                TDT                  <ce>
                                next_to_use          <ce>
                                next_to_clean        <af>
                              buffer_info[next_to_clean]
                                time_stamp           <10012d342>
                                next_to_watch        <ffff8800c8d6fb30>
                                jiffies              <10012d808>
                                desc.status          <0>
Jul 04 11:17:37 frodo kernel: ------------[ cut here ]------------
Jul 04 11:17:37 frodo kernel: WARNING: CPU: 1 PID: 0 at /build/linux-BvkamA/linux-4.4.0/net/sched/sch_generic.c:306 dev_watchdog+0x237/0x240()
Jul 04 11:17:37 frodo kernel: NETDEV WATCHDOG: enp7s0 (igb): transmit queue 3 timed out
Jul 04 11:17:37 frodo kernel: Modules linked in: gpio_ich ipmi_ssif intel_powerclamp coretemp kvm_intel kvm irqbypass bridge stp llc serio_raw input_leds joydev lpc_ich ipmi_si 8250_fintek i2c_ismt mac_hid ipmi_msghandler shpchp ib_iser rdma_cm iw_cm ib_cm ib_sa ib_mad ib_core ib_addr iscsi_tcp libiscsi_tcp libiscsi scsi_transport_iscsi nfsd auth_rpcgss nfs_acl lockd grace sunrpc autofs4 btrfs raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c raid0 multipath linear raid1 hid_generic igb dca ptp crct10dif_pclmul ast crc32_pclmul ttm aesni_intel drm_kms_helper aes_x86_64 syscopyarea lrw sysfillrect usbhid sysimgblt fb_sys_fops gf128mul glue_helper ablk_helper hid pps_core cryptd drm ahci i2c_algo_bit libahci fjes
Jul 04 11:17:37 frodo kernel: CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.4.0-28-generic #47-Ubuntu
Jul 04 11:17:37 frodo kernel: Hardware name: To Be Filled By O.E.M. To Be Filled By O.E.M./C2550D4I, BIOS P2.30 01/26/2016
Jul 04 11:17:37 frodo kernel:  0000000000000286
Jul 04 11:17:37 frodo kernel:  75cb0c3a9fd78e36
Jul 04 11:17:37 frodo kernel:  ffff88022fc83d98
Jul 04 11:17:37 frodo kernel:  ffffffff813eb1a3
Jul 04 11:17:37 frodo kernel: 
Jul 04 11:17:37 frodo kernel:  ffff88022fc83de0
Jul 04 11:17:37 frodo kernel:  ffffffff81d638a8
Jul 04 11:17:37 frodo kernel:  ffff88022fc83dd0
Jul 04 11:17:37 frodo kernel:  ffffffff81081102
Jul 04 11:17:37 frodo kernel: 
Jul 04 11:17:37 frodo kernel:  0000000000000003
Jul 04 11:17:37 frodo kernel:  ffff880035647b00
Jul 04 11:17:37 frodo kernel:  0000000000000001
Jul 04 11:17:37 frodo kernel:  ffff880035630000
Jul 04 11:17:37 frodo kernel: 
Jul 04 11:17:37 frodo kernel: Call Trace:
Jul 04 11:17:37 frodo kernel:  <IRQ> 
Jul 04 11:17:37 frodo kernel:  [<ffffffff813eb1a3>] dump_stack+0x63/0x90
Jul 04 11:17:37 frodo kernel:  [<ffffffff81081102>] warn_slowpath_common+0x82/0xc0
Jul 04 11:17:37 frodo kernel:  [<ffffffff8108119c>] warn_slowpath_fmt+0x5c/0x80
Jul 04 11:17:37 frodo kernel:  [<ffffffff81743187>] dev_watchdog+0x237/0x240
Jul 04 11:17:37 frodo kernel:  [<ffffffff81742f50>] ? qdisc_rcu_free+0x40/0x40
Jul 04 11:17:37 frodo kernel:  [<ffffffff810ec5e5>] call_timer_fn+0x35/0x120
Jul 04 11:17:37 frodo kernel:  [<ffffffff81742f50>] ? qdisc_rcu_free+0x40/0x40
Jul 04 11:17:37 frodo kernel:  [<ffffffff810ecf9a>] run_timer_softirq+0x23a/0x2f0
Jul 04 11:17:37 frodo kernel:  [<ffffffff81085b51>] __do_softirq+0x101/0x290
Jul 04 11:17:37 frodo kernel:  [<ffffffff81085e53>] irq_exit+0xa3/0xb0
Jul 04 11:17:37 frodo kernel:  [<ffffffff8182a162>] smp_apic_timer_interrupt+0x42/0x50
Jul 04 11:17:37 frodo kernel:  [<ffffffff81828422>] apic_timer_interrupt+0x82/0x90
Jul 04 11:17:37 frodo kernel:  <EOI> 
Jul 04 11:17:37 frodo kernel:  [<ffffffff816bd7a1>] ? cpuidle_enter_state+0x111/0x2b0
Jul 04 11:17:37 frodo kernel:  [<ffffffff816bd977>] cpuidle_enter+0x17/0x20
Jul 04 11:17:37 frodo kernel:  [<ffffffff810c3fe2>] call_cpuidle+0x32/0x60
Jul 04 11:17:37 frodo kernel:  [<ffffffff816bd953>] ? cpuidle_select+0x13/0x20
Jul 04 11:17:37 frodo kernel:  [<ffffffff810c42a0>] cpu_startup_entry+0x290/0x350
Jul 04 11:17:37 frodo kernel:  [<ffffffff81051714>] start_secondary+0x154/0x190
Jul 04 11:17:37 frodo kernel: ---[ end trace 330f1f66f4dd6cb8 ]---
Jul 04 11:17:37 frodo kernel: igb 0000:07:00.0 enp7s0: Reset adapter
Jul 04 11:17:37 frodo kernel: br0: port 1(enp7s0) entered disabled state
Jul 04 11:17:41 frodo kernel: igb 0000:07:00.0 enp7s0: igb: enp7s0 NIC Link is Up 1000 Mbps Full Duplex, Flow Control: RX/TX
Jul 04 11:17:41 frodo kernel: br0: port 1(enp7s0) entered forwarding state
Jul 04 11:17:41 frodo kernel: br0: port 1(enp7s0) entered forwarding state
Jul 04 11:20:46 frodo kernel: igb 0000:07:00.0 enp7s0: Reset adapter
Jul 04 11:20:46 frodo kernel: br0: port 1(enp7s0) entered disabled state
Jul 04 11:20:50 frodo kernel: igb 0000:07:00.0 enp7s0: igb: enp7s0 NIC Link is Up 1000 Mbps Full Duplex, Flow Control: RX/TX
Jul 04 11:20:50 frodo kernel: br0: port 1(enp7s0) entered forwarding state
Jul 04 11:20:50 frodo kernel: br0: port 1(enp7s0) entered forwarding state
Jul 04 11:24:01 frodo kernel: br0: port 1(enp7s0) entered disabled state
Jul 04 11:24:02 frodo kernel: device enp7s0 left promiscuous mode
Jul 04 11:24:02 frodo kernel: br0: port 1(enp7s0) entered disabled state
Jul 04 11:24:02 frodo kernel: device enp7s0 entered promiscuous mode
Jul 04 11:24:02 frodo kernel: br0: port 1(enp7s0) entered forwarding state
Jul 04 11:24:02 frodo kernel: br0: port 1(enp7s0) entered forwarding state
Jul 04 11:24:02 frodo kernel: br0: port 1(enp7s0) entered disabled state
Jul 04 11:24:06 frodo kernel: igb 0000:07:00.0 enp7s0: igb: enp7s0 NIC Link is Up 1000 Mbps Full Duplex, Flow Control: RX/TX
Jul 04 11:24:06 frodo kernel: br0: port 1(enp7s0) entered forwarding state
Jul 04 11:24:06 frodo kernel: br0: port 1(enp7s0) entered forwarding state
Jul 04 11:27:54 frodo kernel: igb 0000:08:00.0: removed PHC on enp8s0
Jul 04 11:27:54 frodo kernel: igb 0000:07:00.0: removed PHC on enp7s0
Jul 04 11:27:54 frodo kernel: br0: port 1(enp7s0) entered disabled state
Jul 04 11:27:54 frodo kernel: device enp7s0 left promiscuous mode
Jul 04 11:27:54 frodo kernel: br0: port 1(enp7s0) entered disabled state