I also experienced this problem a few times. Running 10.04 LTS here. At some point my wired network connection just suddenly stops working, restarting networking, using Network Manager to connect/disconnect, or physically removing/inserting the cable doesn't help, I have to reboot the whole machine. The leds on the NIC are flashing though, indicating a connection.
Linux lpt-marc 2.6.32-25-generic #45-Ubuntu SMP Sat Oct 16 19:52:42 UTC 2010 x86_64 GNU/Linux
I also experienced this problem a few times. Running 10.04 LTS here. At some point my wired network connection just suddenly stops working, restarting networking, using Network Manager to connect/disconnect, or physically removing/inserting the cable doesn't help, I have to reboot the whole machine. The leds on the NIC are flashing though, indicating a connection.
Linux lpt-marc 2.6.32-25-generic #45-Ubuntu SMP Sat Oct 16 19:52:42 UTC 2010 x86_64 GNU/Linux
# cat /etc/lsb-release RELEASE= 10.04 CODENAME= lucid DESCRIPTION= "Ubuntu 10.04.1 LTS"
DISTRIB_ID=Ubuntu
DISTRIB_
DISTRIB_
DISTRIB_
From the /var/log/messages:
Oct 27 12:56:46 lpt-marc kernel: [431343.040063] ------------[ cut here ]------------ buildd/ linux-2. 6.32/net/ sched/sch_ generic. c:261 dev_watchdog+ 0x262/0x270( ) efb>] warn_slowpath_ common+ 0x7b/0xc0 fa1>] warn_slowpath_ fmt+0x41/ 0x50 b92>] dev_watchdog+ 0x262/0x270 d27>] ? insert_ work+0x77/ 0xc0 7b9>] ? default_ spin_lock_ flags+0x9/ 0x10 930>] ? dev_watchdog+ 0x0/0x270 88b>] run_timer_ softirq+ 0x19b/0x340 587>] __do_softirq+ 0xb7/0x1e0 540>] ? handle_ IRQ_event+ 0x60/0x170 2ec>] call_softirq+ 0x1c/0x30 cb5>] do_softirq+ 0x65/0xa0 425>] irq_exit+0x85/0x90 a65>] do_IRQ+0x75/0xf0 b13>] ret_from_ intr+0x0/ 0x11 c1d>] ? acpi_idle_ enter_bm+ 0x294/0x2c8 c16>] ? acpi_idle_ enter_bm+ 0x28d/0x2c8 907>] ? cpuidle_ idle_call+ 0xa7/0x140 e73>] ? cpu_idle+0xb3/0x110 72b>] ? rest_init+0x6b/0x80 dcc>] ? start_kernel+ 0x368/0x371 33a>] ? x86_64_ start_reservati ons+0x125/ 0x129 438>] ? x86_64_ start_kernel+ 0xfa/0x109
Oct 27 12:56:46 lpt-marc kernel: [431343.040084] WARNING: at /build/
Oct 27 12:56:46 lpt-marc kernel: [431343.040091] Hardware name: Latitude D830
Oct 27 12:56:46 lpt-marc kernel: [431343.040097] NETDEV WATCHDOG: eth0 (tg3): transmit queue 0 timed out
Oct 27 12:56:46 lpt-marc kernel: [431343.040102] Modules linked in: nls_iso8859_1 nls_cp437 vfat fat binfmt_misc vboxnetadp vboxnetflt vboxdrv vmnet vmblock vsock vmci vmmon ipt_MASQUERADE iptable_nat bridge stp kvm_intel kvm ipt_REJECT xt_comment ipt_LOG xt_limit xt_tcpudp ipt_addrtype xt_state pcmcia usbhid dell_wmi ppdev arc4 ip6table_filter snd_hda_codec_idt ip6_tables nf_nat_irc nf_conntrack_irc nf_nat_ftp nf_nat nf_conntrack_ipv4 nf_defrag_ipv4 nf_conntrack_ftp nf_conntrack iwl3945 iptable_filter iwlcore ip_tables joydev x_tables mac80211 led_class usb_storage parport_pc snd_hda_intel snd_hda_codec snd_hwdep snd_pcm_oss snd_mixer_oss snd_pcm snd_seq_dummy snd_seq_oss snd_seq_midi snd_rawmidi snd_seq_midi_event snd_seq hid snd_timer snd_seq_device dell_laptop video dcdbas nvidia(P) output fbcon tileblit font yenta_socket rsrc_nonstatic pcmcia_core snd bitblit softcursor cfg80211 psmouse serio_raw intel_agp vga16fb vgastate soundcore snd_page_alloc lp parport ohci1394 ieee1394 tg3
Oct 27 12:56:46 lpt-marc kernel: [431343.040283] Pid: 0, comm: swapper Tainted: P 2.6.32-25-generic #45-Ubuntu
Oct 27 12:56:46 lpt-marc kernel: [431343.040289] Call Trace:
Oct 27 12:56:46 lpt-marc kernel: [431343.040294] <IRQ> [<ffffffff81065
Oct 27 12:56:46 lpt-marc kernel: [431343.040315] [<ffffffff81065
Oct 27 12:56:46 lpt-marc kernel: [431343.040324] [<ffffffff81478
Oct 27 12:56:46 lpt-marc kernel: [431343.040334] [<ffffffff8107f
Oct 27 12:56:46 lpt-marc kernel: [431343.040345] [<ffffffff81038
Oct 27 12:56:46 lpt-marc kernel: [431343.040354] [<ffffffff81478
Oct 27 12:56:46 lpt-marc kernel: [431343.040362] [<ffffffff81076
Oct 27 12:56:46 lpt-marc kernel: [431343.040373] [<ffffffff8106d
Oct 27 12:56:46 lpt-marc kernel: [431343.040381] [<ffffffff810c4
Oct 27 12:56:46 lpt-marc kernel: [431343.040391] [<ffffffff81013
Oct 27 12:56:46 lpt-marc kernel: [431343.040398] [<ffffffff81014
Oct 27 12:56:46 lpt-marc kernel: [431343.040406] [<ffffffff8106d
Oct 27 12:56:46 lpt-marc kernel: [431343.040414] [<ffffffff81548
Oct 27 12:56:46 lpt-marc kernel: [431343.040422] [<ffffffff81012
Oct 27 12:56:46 lpt-marc kernel: [431343.040426] <EOI> [<ffffffff8130e
Oct 27 12:56:46 lpt-marc kernel: [431343.040444] [<ffffffff8130e
Oct 27 12:56:46 lpt-marc kernel: [431343.040455] [<ffffffff81439
Oct 27 12:56:46 lpt-marc kernel: [431343.040464] [<ffffffff81010
Oct 27 12:56:46 lpt-marc kernel: [431343.040472] [<ffffffff8152e
Oct 27 12:56:46 lpt-marc kernel: [431343.040482] [<ffffffff8184b
Oct 27 12:56:46 lpt-marc kernel: [431343.040490] [<ffffffff8184b
Oct 27 12:56:46 lpt-marc kernel: [431343.040498] [<ffffffff8184b
Oct 27 12:56:46 lpt-marc kernel: [431343.040505] ---[ end trace a25f9e500e8fa2dc ]---
Oct 27 12:56:46 lpt-marc kernel: [431343.268176] tg3: eth0: Link is down.
Oct 27 12:56:49 lpt-marc kernel: [431346.375485] tg3: eth0: Link is up at 1000 Mbps, full duplex.
Oct 27 12:56:49 lpt-marc kernel: [431346.375492] tg3: eth0: Flow control is on for TX and on for RX.