drop_monitor: fix trace_napi_poll_hit()

The net_dev of backlog napi is NULL, like below:

__get_cpu_var(softnet_data).backlog.dev == NULL

So, we should check it in napi tracepoint's probe function

Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Xiao Guangrong 2009-08-30 20:10:43 +00:00 committed by David S. Miller
parent 3732e9bd2d
commit f2798eb4e0
1 changed files with 2 additions and 1 deletions

View File

@ -182,7 +182,8 @@ static void trace_napi_poll_hit(struct napi_struct *napi)
/*
* Ratelimit our check time to dm_hw_check_delta jiffies
*/
if (!time_after(jiffies, napi->dev->last_rx + dm_hw_check_delta))
if (!napi->dev ||
!time_after(jiffies, napi->dev->last_rx + dm_hw_check_delta))
return;
rcu_read_lock();