Commit 4ae2bb81 authored by Antoine Tenart's avatar Antoine Tenart Committed by Jakub Kicinski
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net-sysfs: take the rtnl lock when accessing xps_rxqs_map and num_tc 



Accesses to dev->xps_rxqs_map (when using dev->num_tc) should be
protected by the rtnl lock, like we do for netif_set_xps_queue. I didn't
see an actual bug being triggered, but let's be safe here and take the
rtnl lock while accessing the map in sysfs.

Fixes: 8af2c06f ("net-sysfs: Add interface for Rx queue(s) map per Tx queue")
Signed-off-by: default avatarAntoine Tenart <atenart@kernel.org>
Reviewed-by: default avatarAlexander Duyck <alexanderduyck@fb.com>
Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 2d57b4f1

net/core/net-sysfs.c

+18 −5
Original line number Original line Diff line number Diff line
@@ -1429,22 +1429,29 @@ static struct netdev_queue_attribute xps_cpus_attribute __ro_after_init 




static ssize_t xps_rxqs_show(struct netdev_queue *queue, char *buf)

static ssize_t xps_rxqs_show(struct netdev_queue *queue, char *buf)

{

{

	int j, len, ret, num_tc = 1, tc = 0;

	struct net_device *dev = queue->dev;

	struct net_device *dev = queue->dev;

	struct xps_dev_maps *dev_maps;

	struct xps_dev_maps *dev_maps;

	unsigned long *mask, index;

	unsigned long *mask, index;

	int j, len, num_tc = 1, tc = 0;





	index = get_netdev_queue_index(queue);

	index = get_netdev_queue_index(queue);





	if (!rtnl_trylock())

		return restart_syscall();



	if (dev->num_tc) {

	if (dev->num_tc) {

		num_tc = dev->num_tc;

		num_tc = dev->num_tc;

		tc = netdev_txq_to_tc(dev, index);

		tc = netdev_txq_to_tc(dev, index);

		if (tc < 0)

		if (tc < 0) {

			return -EINVAL;

			ret = -EINVAL;

			goto err_rtnl_unlock;

		}

	}

	}

	mask = bitmap_zalloc(dev->num_rx_queues, GFP_KERNEL);

	mask = bitmap_zalloc(dev->num_rx_queues, GFP_KERNEL);

	if (!mask)

	if (!mask) {

		return -ENOMEM;

		ret = -ENOMEM;

		goto err_rtnl_unlock;

	}





	rcu_read_lock();

	rcu_read_lock();

	dev_maps = rcu_dereference(dev->xps_rxqs_map);

	dev_maps = rcu_dereference(dev->xps_rxqs_map);
@@ -1470,10 +1477,16 @@ static ssize_t xps_rxqs_show(struct netdev_queue *queue, char *buf) 
out_no_maps:

out_no_maps:

	rcu_read_unlock();

	rcu_read_unlock();





	rtnl_unlock();



	len = bitmap_print_to_pagebuf(false, buf, mask, dev->num_rx_queues);

	len = bitmap_print_to_pagebuf(false, buf, mask, dev->num_rx_queues);

	bitmap_free(mask);

	bitmap_free(mask);





	return len < PAGE_SIZE ? len : -EINVAL;

	return len < PAGE_SIZE ? len : -EINVAL;



err_rtnl_unlock:

	rtnl_unlock();

	return ret;

}

}





static ssize_t xps_rxqs_store(struct netdev_queue *queue, const char *buf,

static ssize_t xps_rxqs_store(struct netdev_queue *queue, const char *buf,