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While using netconsole on forcedeth, lockdep noticed the following locking bug: ================================= [ INFO: inconsistent lock state ] 2.6.24-rc6 #6 Signed-off-by: Ingo Molnar <mingo@elte.hu> --------------------------------- inconsistent {softirq-on-W} -> {in-softirq-W} usage. udevd/719 [HC0[0]:SC1[1]:HE1:SE0] takes: (_xmit_ETHER){-+..}, at: [<c043062e>] dev_watchdog+0x1c/0xb9 {softirq-on-W} state was registered at: [<c0147f67>] mark_held_locks+0x4e/0x66 [<c014810e>] trace_hardirqs_on+0xfe/0x136 [<c048ae63>] _spin_unlock_irq+0x22/0x42 [<c02ec617>] nv_start_xmit_optimized+0x347/0x37a [<c042c80d>] netpoll_send_skb+0xa4/0x147 [<c042d4a6>] netpoll_send_udp+0x238/0x242 [<c02f44f6>] write_msg+0x6d/0x9b [<c012c129>] __call_console_drivers+0x4e/0x5a [<c012c18c>] _call_console_drivers+0x57/0x5b [<c012c2dd>] release_console_sem+0x11c/0x1b9 [<c012caeb>] register_console+0x1eb/0x1f3 [<c06ae673>] init_netconsole+0x119/0x15f [<c069149b>] kernel_init+0x147/0x294 [<c01058cb>] kernel_thread_helper+0x7/0x10 [<ffffffff>] 0xffffffff irq event stamp: 950 hardirqs last enabled at (950): [<c048ae63>] _spin_unlock_irq+0x22/0x42 hardirqs last disabled at (949): [<c048aaf7>] _spin_lock_irq+0xc/0x38 softirqs last enabled at (0): [<c012a29c>] copy_process+0x375/0x126d softirqs last disabled at (947): [<c0106d43>] do_softirq+0x61/0xc6 other info that might help us debug this: no locks held by udevd/719. stack backtrace: Pid: 719, comm: udevd Not tainted 2.6.24-rc6 #6 [<c0105c46>] show_trace_log_lvl+0x12/0x25 [<c01063ec>] show_trace+0xd/0x10 [<c010670c>] dump_stack+0x57/0x5f [<c0147505>] print_usage_bug+0x10a/0x117 [<c0147c38>] mark_lock+0x121/0x402 [<c01488b6>] __lock_acquire+0x3d1/0xb64 [<c0149405>] lock_acquire+0x4e/0x6a [<c048a99b>] _spin_lock+0x23/0x32 [<c043062e>] dev_watchdog+0x1c/0xb9 [<c0133e4a>] run_timer_softirq+0x133/0x193 [<c0130907>] __do_softirq+0x78/0xed [<c0106d43>] do_softirq+0x61/0xc6 ======================= eth1: link down The fix is to disable/restore irqs instead of disable/enable. Signed-off-by: Ingo Molnar <mingo@elte.hu> Cc: Ayaz Abdulla <aabdulla@nvidia.com> Cc: Jeff Garzik <jeff@garzik.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Jeff Garzik <jeff@garzik.org>