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authorKuniyuki Iwashima <kuniyu@amazon.com>2022-07-11 17:15:33 -0700
committerDavid S. Miller <davem@davemloft.net>2022-07-13 12:56:50 +0100
commitbdf00bf24bef9be1ca641a6390fd5487873e0d2e (patch)
treea571db15de0e5ac08997aab9705356eff39685b6 /net/ipv4/nexthop.c
parente49e4aff7ec19b2d0d0957ee30e93dade57dab9e (diff)
downloadlinux-bdf00bf24bef9be1ca641a6390fd5487873e0d2e.tar.gz
nexthop: Fix data-races around nexthop_compat_mode.
While reading nexthop_compat_mode, it can be changed concurrently.
Thus, we need to add READ_ONCE() to its readers.

Fixes: 4f80116d3df3 ("net: ipv4: add sysctl for nexthop api compatibility mode")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/nexthop.c')
-rw-r--r--net/ipv4/nexthop.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/net/ipv4/nexthop.c b/net/ipv4/nexthop.c
index e459a391e607..853a75a8fbaf 100644
--- a/net/ipv4/nexthop.c
+++ b/net/ipv4/nexthop.c
@@ -1858,7 +1858,7 @@ static void __remove_nexthop_fib(struct net *net, struct nexthop *nh)
 		/* __ip6_del_rt does a release, so do a hold here */
 		fib6_info_hold(f6i);
 		ipv6_stub->ip6_del_rt(net, f6i,
-				      !net->ipv4.sysctl_nexthop_compat_mode);
+				      !READ_ONCE(net->ipv4.sysctl_nexthop_compat_mode));
 	}
 }
 
@@ -2361,7 +2361,8 @@ out:
 	if (!rc) {
 		nh_base_seq_inc(net);
 		nexthop_notify(RTM_NEWNEXTHOP, new_nh, &cfg->nlinfo);
-		if (replace_notify && net->ipv4.sysctl_nexthop_compat_mode)
+		if (replace_notify &&
+		    READ_ONCE(net->ipv4.sysctl_nexthop_compat_mode))
 			nexthop_replace_notify(net, new_nh, &cfg->nlinfo);
 	}