[PATCH 6.1 30/71] netrom: Fix data-races around sysctl_net_busy_read

Sasha Levin
2024-03-13T16:40:33Z

From: Jason Xing <kernelxing@tencent.com>

[ Upstream commit d380ce70058a4ccddc3e5f5c2063165dc07672c6 ]

We need to protect the reader reading the sysctl value because the
value can be changed concurrently.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Jason Xing <kernelxing@tencent.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/netrom/af_netrom.c | 2 +-
net/netrom/nr_in.c | 6 +++---
2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/net/netrom/af_netrom.c b/net/netrom/af_netrom.c
index 5472e79cde830..f0879295de110 100644
--- a/net/netrom/af_netrom.c
+++ b/net/netrom/af_netrom.c
@@ -954,7 +954,7 @@ int nr_rx_frame(struct sk_buff *skb, struct net_device *dev)
* G8PZT's Xrouter which is sending packets with command type 7
* as an extension of the protocol.
*/
- if (sysctl_netrom_reset_circuit &&
+ if (READ_ONCE(sysctl_netrom_reset_circuit) &&
(frametype != NR_RESET || flags != 0))
nr_transmit_reset(skb, 1);

diff --git a/net/netrom/nr_in.c b/net/netrom/nr_in.c
index 2f084b6f69d7e..97944db6b5ac6 100644
--- a/net/netrom/nr_in.c
+++ b/net/netrom/nr_in.c
@@ -97,7 +97,7 @@ static int nr_state1_machine(struct sock *sk, struct sk_buff *skb,
break;

case NR_RESET:
- if (sysctl_netrom_reset_circuit)
+ if (READ_ONCE(sysctl_netrom_reset_circuit))
nr_disconnect(sk, ECONNRESET);
break;

@@ -128,7 +128,7 @@ static int nr_state2_machine(struct sock *sk, struct sk_buff *skb,
break;

case NR_RESET:
- if (sysctl_netrom_reset_circuit)
+ if (READ_ONCE(sysctl_netrom_reset_circuit))
nr_disconnect(sk, ECONNRESET);
break;

@@ -262,7 +262,7 @@ static int nr_state3_machine(struct sock *sk, struct sk_buff *skb, int frametype
break;

case NR_RESET:
- if (sysctl_netrom_reset_circuit)
+ if (READ_ONCE(sysctl_netrom_reset_circuit))
nr_disconnect(sk, ECONNRESET);
break;

--
2.43.0