From: Kuniyuki Iwashima <kuniyu@amazon.com>
Date: Tue, 23 Aug 2022 17:46:55 +0000 (-0700)
Subject: net: Fix a data-race around netdev_budget_usecs.
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=fa45d484c52c73f79db2c23b0cdfc6c6455093ad;p=linux.git

net: Fix a data-race around netdev_budget_usecs.

While reading netdev_budget_usecs, it can be changed concurrently.
Thus, we need to add READ_ONCE() to its reader.

Fixes: 7acf8a1e8a28 ("Replace 2 jiffies with sysctl netdev_budget_usecs to enable softirq tuning")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---

diff --git a/net/core/dev.c b/net/core/dev.c
index c83e23cfc57d7..8221322d86db9 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -6665,7 +6665,7 @@ static __latent_entropy void net_rx_action(struct softirq_action *h)
 {
 	struct softnet_data *sd = this_cpu_ptr(&softnet_data);
 	unsigned long time_limit = jiffies +
-		usecs_to_jiffies(netdev_budget_usecs);
+		usecs_to_jiffies(READ_ONCE(netdev_budget_usecs));
 	int budget = READ_ONCE(netdev_budget);
 	LIST_HEAD(list);
 	LIST_HEAD(repoll);