From: Jason Xing <kernelxing@tencent.com>
Date: Mon, 4 Mar 2024 08:20:45 +0000 (+0800)
Subject: netrom: Fix a data-race around sysctl_netrom_link_fails_count
X-Git-Tag: v6.8~19^2~2^2~1
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=bc76645ebdd01be9b9994dac39685a3d0f6f7985;p=thirdparty%2Flinux.git

netrom: Fix a data-race around sysctl_netrom_link_fails_count

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>
---

diff --git a/net/netrom/nr_route.c b/net/netrom/nr_route.c
index 89e12e6eea2ef..70480869ad1c5 100644
--- a/net/netrom/nr_route.c
+++ b/net/netrom/nr_route.c
@@ -728,7 +728,7 @@ void nr_link_failed(ax25_cb *ax25, int reason)
 	nr_neigh->ax25 = NULL;
 	ax25_cb_put(ax25);
 
-	if (++nr_neigh->failed < sysctl_netrom_link_fails_count) {
+	if (++nr_neigh->failed < READ_ONCE(sysctl_netrom_link_fails_count)) {
 		nr_neigh_put(nr_neigh);
 		return;
 	}