From: Joonwoo Park <[EMAIL PROTECTED]> Date: Tue, 22 Jan 2008 00:08:57 +0900
> The rt_run_flush() can be stucked if it was called while netdev is on the > high load. > It's possible when pushing rtable to rt_hash is faster than pulling > from it. > > The commands 'ifconfig up or ifconfig mtu' and netif_carrier_on() can > introduce soft lockup like this: > > [ 363.528001] BUG: soft lockup - CPU#0 stuck for 11s! [events/0:9] > [ 363.531492] > [ 363.535027] Pid: 9, comm: events/0 Not tainted (2.6.24-rc8 #14) > [ 363.538837] EIP: 0060:[<c4086a39>] EFLAGS: 00000286 CPU: 0 > [ 363.542762] EIP is at kfree+0xa9/0xf0 > ... > [ 363.660815] [<c42fb0fd>] skb_release_data+0x5d/0x90 > [ 363.666989] [<c42fb7dc>] skb_release_all+0x5c/0xd0 > [ 363.673207] [<c42faf8b>] __kfree_skb+0xb/0x90 > [ 363.679474] [<c42fb029>] kfree_skb+0x19/0x40 > [ 363.685811] [<c4322d87>] ip_rcv+0x27/0x290 > [ 363.692223] [<c4300ae5>] netif_receive_skb+0x255/0x320 > [ 363.698759] [<f88465aa>] e1000_clean_rx_irq+0x14a/0x4f0 [e1000] > [ 363.705456] [<f88437c2>] e1000_clean+0x62/0x270 [e1000] > [ 363.712217] [<c43031ee>] net_rx_action+0x16e/0x220 > [ 363.719065] [<c40346d7>] __do_softirq+0x87/0x100 > [ 363.726001] [<c40347a7>] do_softirq+0x57/0x60 > [ 363.732979] [<c4034b4e>] local_bh_enable_ip+0xae/0x100 > [ 363.740094] [<c43e73f5>] _spin_unlock_bh+0x25/0x30 > [ 363.747283] [<c431ec88>] rt_run_flush+0xc8/0xe0 > [ 363.754566] [<c4320c76>] rt_cache_flush+0xd6/0xe0 > [ 363.761917] [<c4350269>] fib_netdev_event+0x89/0xa0 > [ 363.769361] [<c4047d67>] notifier_call_chain+0x37/0x80 > ... > > This patch makes rt_run_flush() to run with softirq is disabled. > > Signed-off-by: Joonwoo Park <[EMAIL PROTECTED]> I agree with the analysis of the problem, however not the solution. This will absolutely kill software interrupt latency. In fact, we have moved much of the flush work into a workqueue in net-2.6.25 because of how important that is We need to find some other way to solve this. Eric, any ideas? -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
