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net-sysfs: take the rtnl lock when accessing xps_rxqs_map and num_tc

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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: 8af2c06ff4 ("net-sysfs: Add interface for Rx queue(s) map per Tx queue")
Signed-off-by: Antoine Tenart <atenart@kernel.org>
Reviewed-by: Alexander Duyck <alexanderduyck@fb.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Antoine Tenart 2020-12-23 22:23:23 +01:00 committed by Jakub Kicinski
parent 2d57b4f142
commit 4ae2bb8164
1 changed files with 18 additions and 5 deletions
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23
net/core/net-sysfs.c
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@ -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)
{
int j, len, ret, num_tc = 1, tc = 0;
struct net_device *dev = queue->dev;
struct xps_dev_maps *dev_maps;
unsigned long *mask, index;
int j, len, num_tc = 1, tc = 0;
index = get_netdev_queue_index(queue);
if (!rtnl_trylock())
return restart_syscall();
if (dev->num_tc) {
num_tc = dev->num_tc;
tc = netdev_txq_to_tc(dev, index);
if (tc < 0)
return -EINVAL;
if (tc < 0) {
ret = -EINVAL;
goto err_rtnl_unlock;
}
}
mask = bitmap_zalloc(dev->num_rx_queues, GFP_KERNEL);
if (!mask)
return -ENOMEM;
if (!mask) {
ret = -ENOMEM;
goto err_rtnl_unlock;
}
rcu_read_lock();
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:
rcu_read_unlock();
rtnl_unlock();
len = bitmap_print_to_pagebuf(false, buf, mask, dev->num_rx_queues);
bitmap_free(mask);
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,