[PATCH 5.15 083/136] net: Fix a data-race around netdev_budget_usecs.

Greg Kroah-Hartman
2022-08-29T11:30:46Z

From: Kuniyuki Iwashima <kuniyu@amazon.com>

[ Upstream commit fa45d484c52c73f79db2c23b0cdfc6c6455093ad ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/core/dev.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/core/dev.c b/net/core/dev.c
index fefe8ddd282fd..276cca563325e 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -7137,7 +7137,7 @@ 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);
--
2.35.1