[PATCH 5.4 12/84] bonding: init notify_work earlier to avoid uninitialized use

Greg Kroah-Hartman
2021-06-14T10:53:21Z

From: Johannes Berg <johannes.berg@intel.com>

[ 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@syzkaller.appspotmail.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Acked-by: Jay Vosburgh <jay.vosburgh@canonical.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
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 2bc4cb9e3095..e21643377162 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -1335,6 +1335,7 @@ 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;
@@ -1347,7 +1348,6 @@ static struct slave *bond_alloc_slave(struct bonding *bond,
return NULL;
}
}
- INIT_DELAYED_WORK(&slave->notify_work, bond_netdev_notify_work);

return slave;
}
--
2.30.2