From: Eric Dumazet <edumazet@xxxxxxxxxx>
[ Upstream commit 42c7ded0eeacd2ba5db599205c71c279dc715de7 ]
bond_miimon_commit() is run while RTNL is held, not RCU.
WARNING: suspicious RCU usage
6.1.0-syzkaller-09671-g89529367293c #0 Not tainted
-----------------------------
drivers/net/bonding/bond_main.c:2704 suspicious rcu_dereference_check() usage!
Fixes: e95cc44763a4 ("bonding: do failover when high prio link up")
Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Reported-by: syzbot <syzkaller@xxxxxxxxxxxxxxxx>
Cc: Hangbin Liu <liuhangbin@xxxxxxxxx>
Cc: Jay Vosburgh <j.vosburgh@xxxxxxxxx>
Cc: Veaceslav Falico <vfalico@xxxxxxxxx>
Cc: Andy Gospodarek <andy@xxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20221220130831.1480888-1-edumazet@xxxxxxxxxx
Signed-off-by: Paolo Abeni <pabeni@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/net/bonding/bond_main.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index 771f2a533d3f..7807113e0910 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -2653,10 +2653,12 @@ static void bond_miimon_link_change(struct bonding *bond,
static void bond_miimon_commit(struct bonding *bond)
{
- struct slave *slave, *primary;
+ struct slave *slave, *primary, *active;
bool do_failover = false;
struct list_head *iter;
+ ASSERT_RTNL();
+
bond_for_each_slave(bond, slave, iter) {
switch (slave->link_new_state) {
case BOND_LINK_NOCHANGE:
@@ -2699,8 +2701,8 @@ static void bond_miimon_commit(struct bonding *bond)
bond_miimon_link_change(bond, slave, BOND_LINK_UP);
- if (!rcu_access_pointer(bond->curr_active_slave) || slave == primary ||
- slave->prio > rcu_dereference(bond->curr_active_slave)->prio)
+ active = rtnl_dereference(bond->curr_active_slave);
+ if (!active || slave == primary || slave->prio > active->prio)
do_failover = true;
continue;
--
2.35.1
