[PATCH AUTOSEL 5.6 288/606] drivers: net: hamradio: Fix suspicious RCU usage warning in bpqether.c

Sasha Levin
2020-06-09T00:20:25Z

From: Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>

[ Upstream commit 95f59bf88bb75281cc626e283ecefdd5d5641427 ]

This patch fixes the following warning:
=============================
WARNING: suspicious RCU usage
5.7.0-rc5-next-20200514-syzkaller #0 Not tainted
-----------------------------
drivers/net/hamradio/bpqether.c:149 RCU-list traversed in non-reader section!!

Since rtnl lock is held, pass this cond in list_for_each_entry_rcu().

Reported-by: syzbot+bb82cafc737c002d11ca@syzkaller.appspotmail.com
Signed-off-by: Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/hamradio/bpqether.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/net/hamradio/bpqether.c b/drivers/net/hamradio/bpqether.c
index fbea6f232819..e2ad3c2e8df5 100644
--- a/drivers/net/hamradio/bpqether.c
+++ b/drivers/net/hamradio/bpqether.c
@@ -127,7 +127,8 @@ static inline struct net_device *bpq_get_ax25_dev(struct net_device *dev)
{
struct bpqdev *bpq;

- list_for_each_entry_rcu(bpq, &bpq_devices, bpq_list) {
+ list_for_each_entry_rcu(bpq, &bpq_devices, bpq_list,
+ lockdep_rtnl_is_held()) {
if (bpq->ethdev == dev)
return bpq->axdev;
}
--
2.25.1