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Diffstat (limited to 'net/core/drop_monitor.c')
-rw-r--r--net/core/drop_monitor.c11
1 files changed, 9 insertions, 2 deletions
diff --git a/net/core/drop_monitor.c b/net/core/drop_monitor.c
index 7b288a121a41..d5dc6be2522c 100644
--- a/net/core/drop_monitor.c
+++ b/net/core/drop_monitor.c
@@ -283,13 +283,17 @@ static void trace_napi_poll_hit(void *ignore, struct napi_struct *napi,
rcu_read_lock();
list_for_each_entry_rcu(new_stat, &hw_stats_list, list) {
+ struct net_device *dev;
+
/*
* only add a note to our monitor buffer if:
* 1) this is the dev we received on
* 2) its after the last_rx delta
* 3) our rx_dropped count has gone up
*/
- if ((new_stat->dev == napi->dev) &&
+ /* Paired with WRITE_ONCE() in dropmon_net_event() */
+ dev = READ_ONCE(new_stat->dev);
+ if ((dev == napi->dev) &&
(time_after(jiffies, new_stat->last_rx + dm_hw_check_delta)) &&
(napi->dev->stats.rx_dropped != new_stat->last_drop_val)) {
trace_drop_common(NULL, NULL);
@@ -1576,7 +1580,10 @@ static int dropmon_net_event(struct notifier_block *ev_block,
mutex_lock(&net_dm_mutex);
list_for_each_entry_safe(new_stat, tmp, &hw_stats_list, list) {
if (new_stat->dev == dev) {
- new_stat->dev = NULL;
+
+ /* Paired with READ_ONCE() in trace_napi_poll_hit() */
+ WRITE_ONCE(new_stat->dev, NULL);
+
if (trace_state == TRACE_OFF) {
list_del_rcu(&new_stat->list);
kfree_rcu(new_stat, rcu);