Commit d3e6e285 authored Jun 03, 2019 by Florian Westphal Committed by David S. Miller Jun 04, 2019

net: ipv4: fix rcu lockdep splat due to wrong annotation



syzbot triggered following splat when strict netlink
validation is enabled:

net/ipv4/devinet.c:1766 suspicious rcu_dereference_check() usage!

This occurs because we hold RTNL mutex, but no rcu read lock.
The second call site holds both, so just switch to the _rtnl variant.

Reported-by:  <syzbot+bad6e32808a3a97b1515@syzkaller.appspotmail.com>
Fixes: 2638eb8b ("net: ipv4: provide __rcu annotation for ifa_list")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent ae95f9c1

net/ipv4/devinet.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -1763,7 +1763,7 @@ static int in_dev_dump_addr(struct in_device in_dev, struct sk_buff skb,
		int ip_idx = 0;
		int err;

		in_dev_for_each_ifa_rcu(ifa, in_dev) {
		in_dev_for_each_ifa_rtnl(ifa, in_dev) {
		if (ip_idx < s_ip_idx) {
		ip_idx++;
		continue;