From: Kuniyuki Iwashima <kuniyu@amazon.com>
Date: Tue, 23 Aug 2022 17:46:53 +0000 (-0700)
Subject: net: Fix a data-race around netdev_budget.
X-Git-Tag: v5.10.140~31
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=12a34d7f0463ebb6db01977091b5cda46d9060bc;p=thirdparty%2Fkernel%2Fstable.git

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 1ea75768c5b23..c4eb1b666a21c 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -6880,7 +6880,7 @@ 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);