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>
diff --git a/net/core/drop_monitor.c b/net/core/drop_monitor.c
index 9d66fa9..d311202 100644
--- a/net/core/drop_monitor.c
+++ b/net/core/drop_monitor.c
@@ -182,7 +182,8 @@
/*
* 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();