* [PATCH net] af_packet: set defaule value for tmo
@ 2019-12-09 13:31 Mao Wenan
2019-12-09 14:14 ` walter harms
2019-12-09 22:31 ` David Miller
0 siblings, 2 replies; 3+ messages in thread
From: Mao Wenan @ 2019-12-09 13:31 UTC (permalink / raw)
To: davem, loke.chetan, willemb, edumazet, maximmi, nhorman, pabeni,
maowenan, yuehaibing, tglx
Cc: netdev, linux-kernel, kernel-janitors, Xiao Jiangfeng
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>
---
net/packet/af_packet.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index 53c1d41fb1c9..118cd66b7516 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -544,7 +544,8 @@ static int prb_calc_retire_blk_tmo(struct packet_sock *po,
msec = 1;
div = ecmd.base.speed / 1000;
}
- }
+ } else
+ return DEFAULT_PRB_RETIRE_TOV;
mbits = (blk_size_in_bytes * 8) / (1024 * 1024);
--
2.20.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH net] af_packet: set defaule value for tmo
2019-12-09 13:31 [PATCH net] af_packet: set defaule value for tmo Mao Wenan
@ 2019-12-09 14:14 ` walter harms
2019-12-09 22:31 ` David Miller
1 sibling, 0 replies; 3+ messages in thread
From: walter harms @ 2019-12-09 14:14 UTC (permalink / raw)
To: Mao Wenan
Cc: davem, loke.chetan, willemb, edumazet, maximmi, nhorman, pabeni,
yuehaibing, tglx, netdev, linux-kernel, kernel-janitors,
Xiao Jiangfeng
Am 09.12.2019 14:31, schrieb Mao Wenan:
> 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>
> ---
> net/packet/af_packet.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
> index 53c1d41fb1c9..118cd66b7516 100644
> --- a/net/packet/af_packet.c
> +++ b/net/packet/af_packet.c
> @@ -544,7 +544,8 @@ static int prb_calc_retire_blk_tmo(struct packet_sock *po,
> msec = 1;
> div = ecmd.base.speed / 1000;
> }
> - }
> + } else
> + return DEFAULT_PRB_RETIRE_TOV;
>
> mbits = (blk_size_in_bytes * 8) / (1024 * 1024);
>
With some litrle refactoring you can save one indent
and make it more readable.
err = __ethtool_get_settings(dev, &ecmd);
if (err)
return DEFAULT_PRB_RETIRE_TOV;
speed = ethtool_cmd_speed(&ecmd);
if (speed < SPEED_1000 || speed == SPEED_UNKNOWN)
return DEFAULT_PRB_RETIRE_TOV;
msec = 1; // never changes - needed at all ??
div = speed / 1000;
jm2c
re,
wh
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH net] af_packet: set defaule value for tmo
2019-12-09 13:31 [PATCH net] af_packet: set defaule value for tmo Mao Wenan
2019-12-09 14:14 ` walter harms
@ 2019-12-09 22:31 ` David Miller
1 sibling, 0 replies; 3+ messages in thread
From: David Miller @ 2019-12-09 22:31 UTC (permalink / raw)
To: maowenan
Cc: loke.chetan, willemb, edumazet, maximmi, nhorman, pabeni,
yuehaibing, tglx, netdev, linux-kernel, kernel-janitors,
xiaojiangfeng
From: Mao Wenan <maowenan@huawei.com>
Date: Mon, 9 Dec 2019 21:31:25 +0800
> 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>
Applied, thanks.
^ permalink raw reply [flat|nested] 3+ messages in thread
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2019-12-09 14:14 ` walter harms
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