[PATCH 1/3] drop_monitor: fix trace_napi_poll_hit()

From: Xiao Guangrong
Date: Thu Aug 27 2009 - 06:41:04 EST


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

Signed-off-by: Xiao Guangrong <xiaoguangrong@xxxxxxxxxxxxxx>
---
net/core/drop_monitor.c | 3 ++-
1 files changed, 2 insertions(+), 1 deletions(-)

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 @@ 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();
--
1.6.1.2

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