netrom: Fix data-races around sysctl_net_busy_read

[ 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>

diff --git a/net/netrom/af_netrom.c b/net/netrom/af_netrom.c
index 376b6af431448607f7eff0eb7f5eb48b9670a3f7..37d0bf6cab4562c21aeb51f79f301abb8ee22f4d 100644 (file)
--- 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 69e58906c32b1e8308cd423dc59eb57670d14638..034f79d11ae11ccb85daaf2f9944dc374f73971a 100644 (file)
--- 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;
 
@@ -263,7 +263,7 @@ 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;