From b37f78f234bf4fd98979d6c3ccc0f85e508f978f Mon Sep 17 00:00:00 2001 From: Subash Abhinov Kasiviswanathan Date: Fri, 16 Feb 2018 15:56:37 -0700 Subject: [PATCH] net: qualcomm: rmnet: Fix crash on real dev unregistration With CONFIG_DEBUG_PREEMPT enabled, a crash with the following call stack was observed when removing a real dev which had rmnet devices attached to it. To fix this, remove the netdev_upper link APIs and instead use the existing information in rmnet_port and rmnet_priv to get the association between real and rmnet devs. BUG: sleeping function called from invalid context in_atomic(): 0, irqs_disabled(): 0, pid: 5762, name: ip Preemption disabled at: [] debug_object_active_state+0xa4/0x16c Internal error: Oops - BUG: 0 [#1] PREEMPT SMP Modules linked in: PC is at ___might_sleep+0x13c/0x180 LR is at ___might_sleep+0x17c/0x180 [] ___might_sleep+0x13c/0x180 [] __might_sleep+0x58/0x8c [] mutex_lock+0x2c/0x48 [] kernfs_remove_by_name_ns+0x48/0xa8 [] sysfs_remove_link+0x30/0x58 [] __netdev_adjacent_dev_remove+0x14c/0x1e0 [] __netdev_adjacent_dev_unlink_lists+0x40/0x68 [] netdev_upper_dev_unlink+0xb4/0x1fc [] rmnet_dev_walk_unreg+0x6c/0xc8 [] netdev_walk_all_lower_dev_rcu+0x58/0xb4 [] rmnet_config_notify_cb+0xf4/0x134 [] raw_notifier_call_chain+0x58/0x78 [] call_netdevice_notifiers_info+0x48/0x78 [] rollback_registered_many+0x230/0x3c8 [] unregister_netdevice_many+0x38/0x94 [] rtnl_delete_link+0x58/0x88 [] rtnl_dellink+0xbc/0x1cc [] rtnetlink_rcv_msg+0xb0/0x244 [] netlink_rcv_skb+0xb4/0xdc [] rtnetlink_rcv+0x34/0x44 [] netlink_unicast+0x1ec/0x294 [] netlink_sendmsg+0x320/0x390 [] sock_sendmsg+0x54/0x60 [] ___sys_sendmsg+0x298/0x2b0 [] SyS_sendmsg+0xb4/0xf0 [] el0_svc_naked+0x24/0x28 Fixes: ceed73a2cf4a ("drivers: net: ethernet: qualcomm: rmnet: Initial implementation") Fixes: 60d58f971c10 ("net: qualcomm: rmnet: Implement bridge mode") Signed-off-by: Subash Abhinov Kasiviswanathan Signed-off-by: David S. Miller --- .../ethernet/qualcomm/rmnet/rmnet_config.c | 68 ++++--------------- 1 file changed, 14 insertions(+), 54 deletions(-) diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_config.c b/drivers/net/ethernet/qualcomm/rmnet/rmnet_config.c index 7e7704daf5f1..c4949183eef3 100644 --- a/drivers/net/ethernet/qualcomm/rmnet/rmnet_config.c +++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_config.c @@ -43,12 +43,6 @@ /* Local Definitions and Declarations */ -struct rmnet_walk_data { - struct net_device *real_dev; - struct list_head *head; - struct rmnet_port *port; -}; - static int rmnet_is_real_dev_registered(const struct net_device *real_dev) { return rcu_access_pointer(real_dev->rx_handler) == rmnet_rx_handler; @@ -112,17 +106,14 @@ static int rmnet_register_real_device(struct net_device *real_dev) static void rmnet_unregister_bridge(struct net_device *dev, struct rmnet_port *port) { - struct net_device *rmnet_dev, *bridge_dev; struct rmnet_port *bridge_port; + struct net_device *bridge_dev; if (port->rmnet_mode != RMNET_EPMODE_BRIDGE) return; /* bridge slave handling */ if (!port->nr_rmnet_devs) { - rmnet_dev = netdev_master_upper_dev_get_rcu(dev); - netdev_upper_dev_unlink(dev, rmnet_dev); - bridge_dev = port->bridge_ep; bridge_port = rmnet_get_port_rtnl(bridge_dev); @@ -132,9 +123,6 @@ static void rmnet_unregister_bridge(struct net_device *dev, bridge_dev = port->bridge_ep; bridge_port = rmnet_get_port_rtnl(bridge_dev); - rmnet_dev = netdev_master_upper_dev_get_rcu(bridge_dev); - netdev_upper_dev_unlink(bridge_dev, rmnet_dev); - rmnet_unregister_real_device(bridge_dev, bridge_port); } } @@ -173,10 +161,6 @@ static int rmnet_newlink(struct net *src_net, struct net_device *dev, if (err) goto err1; - err = netdev_master_upper_dev_link(dev, real_dev, NULL, NULL, extack); - if (err) - goto err2; - port->rmnet_mode = mode; hlist_add_head_rcu(&ep->hlnode, &port->muxed_ep[mux_id]); @@ -193,8 +177,6 @@ static int rmnet_newlink(struct net *src_net, struct net_device *dev, return 0; -err2: - rmnet_vnd_dellink(mux_id, port, ep); err1: rmnet_unregister_real_device(real_dev, port); err0: @@ -204,14 +186,13 @@ err0: static void rmnet_dellink(struct net_device *dev, struct list_head *head) { + struct rmnet_priv *priv = netdev_priv(dev); struct net_device *real_dev; struct rmnet_endpoint *ep; struct rmnet_port *port; u8 mux_id; - rcu_read_lock(); - real_dev = netdev_master_upper_dev_get_rcu(dev); - rcu_read_unlock(); + real_dev = priv->real_dev; if (!real_dev || !rmnet_is_real_dev_registered(real_dev)) return; @@ -219,7 +200,6 @@ static void rmnet_dellink(struct net_device *dev, struct list_head *head) port = rmnet_get_port_rtnl(real_dev); mux_id = rmnet_vnd_get_mux(dev); - netdev_upper_dev_unlink(dev, real_dev); ep = rmnet_get_endpoint(port, mux_id); if (ep) { @@ -233,30 +213,13 @@ static void rmnet_dellink(struct net_device *dev, struct list_head *head) unregister_netdevice_queue(dev, head); } -static int rmnet_dev_walk_unreg(struct net_device *rmnet_dev, void *data) -{ - struct rmnet_walk_data *d = data; - struct rmnet_endpoint *ep; - u8 mux_id; - - mux_id = rmnet_vnd_get_mux(rmnet_dev); - ep = rmnet_get_endpoint(d->port, mux_id); - if (ep) { - hlist_del_init_rcu(&ep->hlnode); - rmnet_vnd_dellink(mux_id, d->port, ep); - kfree(ep); - } - netdev_upper_dev_unlink(rmnet_dev, d->real_dev); - unregister_netdevice_queue(rmnet_dev, d->head); - - return 0; -} - static void rmnet_force_unassociate_device(struct net_device *dev) { struct net_device *real_dev = dev; - struct rmnet_walk_data d; + struct hlist_node *tmp_ep; + struct rmnet_endpoint *ep; struct rmnet_port *port; + unsigned long bkt_ep; LIST_HEAD(list); if (!rmnet_is_real_dev_registered(real_dev)) @@ -264,16 +227,19 @@ static void rmnet_force_unassociate_device(struct net_device *dev) ASSERT_RTNL(); - d.real_dev = real_dev; - d.head = &list; - port = rmnet_get_port_rtnl(dev); - d.port = port; rcu_read_lock(); rmnet_unregister_bridge(dev, port); - netdev_walk_all_lower_dev_rcu(real_dev, rmnet_dev_walk_unreg, &d); + hash_for_each_safe(port->muxed_ep, bkt_ep, tmp_ep, ep, hlnode) { + unregister_netdevice_queue(ep->egress_dev, &list); + rmnet_vnd_dellink(ep->mux_id, port, ep); + + hlist_del_init_rcu(&ep->hlnode); + kfree(ep); + } + rcu_read_unlock(); unregister_netdevice_many(&list); @@ -422,11 +388,6 @@ int rmnet_add_bridge(struct net_device *rmnet_dev, if (err) return -EBUSY; - err = netdev_master_upper_dev_link(slave_dev, rmnet_dev, NULL, NULL, - extack); - if (err) - return -EINVAL; - slave_port = rmnet_get_port(slave_dev); slave_port->rmnet_mode = RMNET_EPMODE_BRIDGE; slave_port->bridge_ep = real_dev; @@ -449,7 +410,6 @@ int rmnet_del_bridge(struct net_device *rmnet_dev, port->rmnet_mode = RMNET_EPMODE_VND; port->bridge_ep = NULL; - netdev_upper_dev_unlink(slave_dev, rmnet_dev); slave_port = rmnet_get_port(slave_dev); rmnet_unregister_real_device(slave_dev, slave_port); -- 2.30.2