net: Fix a data-race around netdev_budget.

[ Upstream commit 2e0c42374ee32e72948559d2ae2f7ba3dc6b977c ]

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

Fixes: 51b0bdedb8e7 ("[NET]: Separate two usages of netdev_max_backlog.")
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>

diff --git a/net/core/dev.c b/net/core/dev.c
index 34282b93c3f60abce0e290b469877f40ed8bcb47..a330f936293148c43317382f4af8d0ddb7f80079 100644 (file)
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -6647,7 +6647,7 @@ 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);
-       int budget = netdev_budget;
+       int budget = READ_ONCE(netdev_budget);
        LIST_HEAD(list);
        LIST_HEAD(repoll);