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Commit b37f78f2 authored by Subash Abhinov Kasiviswanathan's avatar Subash Abhinov Kasiviswanathan Committed by David S. Miller
Browse files

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:
[<ffffff9d49043564>] 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
[<ffffff9d48ce0924>] ___might_sleep+0x13c/0x180
[<ffffff9d48ce09c0>] __might_sleep+0x58/0x8c
[<ffffff9d49d6253c>] mutex_lock+0x2c/0x48
[<ffffff9d48ed4840>] kernfs_remove_by_name_ns+0x48/0xa8
[<ffffff9d48ed6ec8>] sysfs_remove_link+0x30/0x58
[<ffffff9d49b05840>] __netdev_adjacent_dev_remove+0x14c/0x1e0
[<ffffff9d49b05914>] __netdev_adjacent_dev_unlink_lists+0x40/0x68
[<ffffff9d49b08820>] netdev_upper_dev_unlink+0xb4/0x1fc
[<ffffff9d494a29f0>] rmnet_dev_walk_unreg+0x6c/0xc8
[<ffffff9d49b00b40>] netdev_walk_all_lower_dev_rcu+0x58/0xb4
[<ffffff9d494a30fc>] rmnet_config_notify_cb+0xf4/0x134
[<ffffff9d48cd21b4>] raw_notifier_call_chain+0x58/0x78
[<ffffff9d49b028a4>] call_netdevice_notifiers_info+0x48/0x78
[<ffffff9d49b0b568>] rollback_registered_many+0x230/0x3c8
[<ffffff9d49b0b738>] unregister_netdevice_many+0x38/0x94
[<ffffff9d49b1e110>] rtnl_delete_link+0x58/0x88
[<ffffff9d49b201dc>] rtnl_dellink+0xbc/0x1cc
[<ffffff9d49b2355c>] rtnetlink_rcv_msg+0xb0/0x244
[<ffffff9d49b5230c>] netlink_rcv_skb+0xb4/0xdc
[<ffffff9d49b204f4>] rtnetlink_rcv+0x34/0x44
[<ffffff9d49b51af0>] netlink_unicast+0x1ec/0x294
[<ffffff9d49b51fdc>] netlink_sendmsg+0x320/0x390
[<ffffff9d49ae6858>] sock_sendmsg+0x54/0x60
[<ffffff9d49ae6f94>] ___sys_sendmsg+0x298/0x2b0
[<ffffff9d49ae98f8>] SyS_sendmsg+0xb4/0xf0
[<ffffff9d48c83770>] el0_svc_naked+0x24/0x28

Fixes: ceed73a2 ("drivers: net: ethernet: qualcomm: rmnet: Initial implementation")
Fixes: 60d58f97 ("net: qualcomm: rmnet: Implement bridge mode")
Signed-off-by: default avatarSubash Abhinov Kasiviswanathan <subashab@codeaurora.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 9ab2323c

drivers/net/ethernet/qualcomm/rmnet/rmnet_config.c

+14 −54
Original line number Diff line number Diff line
@@ -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 @@ static int rmnet_newlink(struct net *src_net, struct net_device *dev, 


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);