current/SOURCES/net-fix-a-data-race-around-sysctl_net_busy_read.patch

From 9181e44fd86a23e957c81a25ba3c923fdcb0aac8 Mon Sep 17 00:00:00 2001
From: Sasha Levin <sashal@kernel.org>
Date: Tue, 23 Aug 2022 10:46:52 -0700
Subject: net: Fix a data-race around sysctl_net_busy_read.

From: Kuniyuki Iwashima <kuniyu@amazon.com>

[ Upstream commit e59ef36f0795696ab229569c153936bfd068d21c ]

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

Fixes: 2d48d67fa8cd ("net: poll/select low latency socket support")
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/sock.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/core/sock.c b/net/core/sock.c
index d672e63a5c2d4..16ab5ef749c60 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -3365,7 +3365,7 @@ void sock_init_data(struct socket *sock, struct sock *sk)
 
 #ifdef CONFIG_NET_RX_BUSY_POLL
        sk->sk_napi_id          =       0;
-       sk->sk_ll_usec          =       sysctl_net_busy_read;
+       sk->sk_ll_usec          =       READ_ONCE(sysctl_net_busy_read);
 #endif
 
        sk->sk_max_pacing_rate = ~0UL;
-- 
2.35.1

1	From 9181e44fd86a23e957c81a25ba3c923fdcb0aac8 Mon Sep 17 00:00:00 2001
2	From: Sasha Levin <sashal@kernel.org>
3	Date: Tue, 23 Aug 2022 10:46:52 -0700
4	Subject: net: Fix a data-race around sysctl_net_busy_read.
5
6	From: Kuniyuki Iwashima <kuniyu@amazon.com>
7
8	[ Upstream commit e59ef36f0795696ab229569c153936bfd068d21c ]
9
10	While reading sysctl_net_busy_read, it can be changed concurrently.
11	Thus, we need to add READ_ONCE() to its reader.
12
13	Fixes: 2d48d67fa8cd ("net: poll/select low latency socket support")
14	Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
15	Signed-off-by: David S. Miller <davem@davemloft.net>
16	Signed-off-by: Sasha Levin <sashal@kernel.org>
17	---
18	net/core/sock.c \| 2 +-
19	1 file changed, 1 insertion(+), 1 deletion(-)
20
21	diff --git a/net/core/sock.c b/net/core/sock.c
22	index d672e63a5c2d4..16ab5ef749c60 100644
23	--- a/net/core/sock.c
24	+++ b/net/core/sock.c
25	@@ -3365,7 +3365,7 @@ void sock_init_data(struct socket sock, struct sock sk)
26
27	#ifdef CONFIG_NET_RX_BUSY_POLL
28	sk->sk_napi_id = 0;
29	- sk->sk_ll_usec = sysctl_net_busy_read;
30	+ sk->sk_ll_usec = READ_ONCE(sysctl_net_busy_read);
31	#endif
32
33	sk->sk_max_pacing_rate = ~0UL;
34	--
35	2.35.1
36