[PATCH 5.10 050/112] net: Fix data-races around sysctl_mem.

Greg Kroah-Hartman
2022-07-19T12:23:18Z

From: Kuniyuki Iwashima <kuniyu@amazon.com>

[ Upstream commit 310731e2f1611d1d13aae237abcf8e66d33345d5 ]

While reading .sysctl_mem, it can be changed concurrently.
So, we need to add READ_ONCE() to avoid data-races.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
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>
---
include/net/sock.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/net/sock.h b/include/net/sock.h
index 2c11eb4abdd2..83854cec4a47 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -1445,7 +1445,7 @@ void __sk_mem_reclaim(struct sock *sk, int amount);
/* sysctl_mem values are in pages, we convert them in SK_MEM_QUANTUM units */
static inline long sk_prot_mem_limits(const struct sock *sk, int index)
{
- long val = sk->sk_prot->sysctl_mem[index];
+ long val = READ_ONCE(sk->sk_prot->sysctl_mem[index]);

#if PAGE_SIZE > SK_MEM_QUANTUM
val <<= PAGE_SHIFT - SK_MEM_QUANTUM_SHIFT;
--
2.35.1