From fcfb894d5952786db3b2b2b9cd3a95cdcedb6ff0 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Wed, 12 Jan 2022 04:53:00 -0800 Subject: net: bridge: fix net device refcount tracking issue in error path I left one dev_put() in br_add_if() error path and sure enough syzbot found its way. As the tracker is allocated in new_nbp(), we must make sure to properly free it. We have to call dev_put_track(dev, &p->dev_tracker) before @p object is freed, of course. This is not an issue because br_add_if() owns a reference on @dev. Fixes: b2dcdc7f731d ("net: bridge: add net device refcount tracker") Signed-off-by: Eric Dumazet Reported-by: syzbot Signed-off-by: David S. Miller --- net/bridge/br_if.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'net') diff --git a/net/bridge/br_if.c b/net/bridge/br_if.c index a52ad81596b7..55f47cadb114 100644 --- a/net/bridge/br_if.c +++ b/net/bridge/br_if.c @@ -615,6 +615,7 @@ int br_add_if(struct net_bridge *br, struct net_device *dev, err = dev_set_allmulti(dev, 1); if (err) { br_multicast_del_port(p); + dev_put_track(dev, &p->dev_tracker); kfree(p); /* kobject not yet init'd, manually free */ goto err1; } @@ -724,10 +725,10 @@ err3: sysfs_remove_link(br->ifobj, p->dev->name); err2: br_multicast_del_port(p); + dev_put_track(dev, &p->dev_tracker); kobject_put(&p->kobj); dev_set_allmulti(dev, -1); err1: - dev_put(dev); return err; } -- cgit v1.2.3