Commit 6727f39e authored Jul 18, 2022 by Kuniyuki Iwashima Committed by Greg Kroah-Hartman Jul 29, 2022

ipv4: Fix a data-race around sysctl_fib_multipath_use_neigh.



[ Upstream commit 87507bcb4f5de16bb419e9509d874f4db6c0ad0f ]

While reading sysctl_fib_multipath_use_neigh, it can be changed
concurrently.  Thus, we need to add READ_ONCE() to its reader.

Fixes: a6db4494 ("net: ipv4: Consider failed nexthops in multipath routes")
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>

parent a8569f76

net/ipv4/fib_semantics.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -2209,7 +2209,7 @@ void fib_select_multipath(struct fib_result *res, int hash)
		}

		change_nexthops(fi) {
		if (net->ipv4.sysctl_fib_multipath_use_neigh) {
		if (READ_ONCE(net->ipv4.sysctl_fib_multipath_use_neigh)) {
		if (!fib_good_nh(nexthop_nh))
		continue;
		if (!first) {