[PATCH AUTOSEL 4.14 05/18] bonding: init notify_work earlier to avoid uninitialized use

From: Sasha Levin
Date: Thu Jun 03 2021 - 13:15:30 EST

From: Johannes Berg <johannes.berg@xxxxxxxxx>

[ Upstream commit 35d96e631860226d5dc4de0fad0a415362ec2457 ]

If bond_kobj_init() or later kzalloc() in bond_alloc_slave() fail,
then we call kobject_put() on the slave->kobj. This in turn calls
the release function slave_kobj_release() which will always try to
cancel_delayed_work_sync(&slave->notify_work), which shouldn't be
done on an uninitialized work struct.

Always initialize the work struct earlier to avoid problems here.

Syzbot bisected this down to a completely pointless commit, some
fault injection may have been at work here that caused the alloc
failure in the first place, which may interact badly with bisect.

Reported-by: syzbot+bfda097c12a00c8cae67@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Johannes Berg <johannes.berg@xxxxxxxxx>
Acked-by: Jay Vosburgh <jay.vosburgh@xxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
drivers/net/bonding/bond_main.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index 1250983616ef..340e7bf6463e 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -1295,6 +1295,7 @@ static struct slave *bond_alloc_slave(struct bonding *bond,

slave->bond = bond;
slave->dev = slave_dev;
+ INIT_DELAYED_WORK(&slave->notify_work, bond_netdev_notify_work);

if (bond_kobj_init(slave))
return NULL;
@@ -1307,7 +1308,6 @@ static struct slave *bond_alloc_slave(struct bonding *bond,
return NULL;
- INIT_DELAYED_WORK(&slave->notify_work, bond_netdev_notify_work);

return slave;