3.16.83-rc1 review patch. If anyone has any objections, please let me know.
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From: Mao Wenan maowenan@huawei.com
commit b43d1f9f7067c6759b1051e8ecb84e82cef569fe upstream.
There is softlockup when using TPACKET_V3: ... NMI watchdog: BUG: soft lockup - CPU#2 stuck for 60010ms! (__irq_svc) from [<c0558a0c>] (_raw_spin_unlock_irqrestore+0x44/0x54) (_raw_spin_unlock_irqrestore) from [<c027b7e8>] (mod_timer+0x210/0x25c) (mod_timer) from [<c0549c30>] (prb_retire_rx_blk_timer_expired+0x68/0x11c) (prb_retire_rx_blk_timer_expired) from [<c027a7ac>] (call_timer_fn+0x90/0x17c) (call_timer_fn) from [<c027ab6c>] (run_timer_softirq+0x2d4/0x2fc) (run_timer_softirq) from [<c021eaf4>] (__do_softirq+0x218/0x318) (__do_softirq) from [<c021eea0>] (irq_exit+0x88/0xac) (irq_exit) from [<c0240130>] (msa_irq_exit+0x11c/0x1d4) (msa_irq_exit) from [<c0209cf0>] (handle_IPI+0x650/0x7f4) (handle_IPI) from [<c02015bc>] (gic_handle_irq+0x108/0x118) (gic_handle_irq) from [<c0558ee4>] (__irq_usr+0x44/0x5c) ...
If __ethtool_get_link_ksettings() is failed in prb_calc_retire_blk_tmo(), msec and tmo will be zero, so tov_in_jiffies is zero and the timer expire for retire_blk_timer is turn to mod_timer(&pkc->retire_blk_timer, jiffies + 0), which will trigger cpu usage of softirq is 100%.
Fixes: f6fb8f100b80 ("af-packet: TPACKET_V3 flexible buffer implementation.") Tested-by: Xiao Jiangfeng xiaojiangfeng@huawei.com Signed-off-by: Mao Wenan maowenan@huawei.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Ben Hutchings ben@decadent.org.uk --- net/packet/af_packet.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
--- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -608,7 +608,8 @@ static int prb_calc_retire_blk_tmo(struc msec = 1; div = speed / 1000; } - } + } else + return DEFAULT_PRB_RETIRE_TOV;
mbits = (blk_size_in_bytes * 8) / (1024 * 1024);