diff options
| author | Alexander Duyck <alexanderduyck@fb.com> | 2021-02-08 14:29:18 -0800 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2021-02-08 15:07:50 -0800 |
| commit | b2f175648031b8b22927220abd3b081f1a12e628 (patch) | |
| tree | 480dae4449566e4c465065a9cd26bcde1c7dcdf8 /net/core/net-sysfs.c | |
| parent | 796c9015ab8d41a66e35fb45c61c60676fc7dc41 (diff) | |
net-sysfs: Add rtnl locking for getting Tx queue traffic class
In order to access the suboordinate dev for a device we should be holding
the rtnl_lock when outside of the transmit path. The existing code was not
doing that for the sysfs dump function and as a result we were open to a
possible race.
To resolve that take the rtnl lock prior to accessing the sb_dev field of
the Tx queue and release it after we have retrieved the tc for the queue.
Signed-off-by: Alexander Duyck <alexanderduyck@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core/net-sysfs.c')
| -rw-r--r-- | net/core/net-sysfs.c | 13 |
1 files changed, 10 insertions, 3 deletions
diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c index daf502c13d6d..91afb0b6de69 100644 --- a/net/core/net-sysfs.c +++ b/net/core/net-sysfs.c @@ -1136,18 +1136,25 @@ static ssize_t traffic_class_show(struct netdev_queue *queue, char *buf) { struct net_device *dev = queue->dev; + int num_tc, tc; int index; - int tc; if (!netif_is_multiqueue(dev)) return -ENOENT; + if (!rtnl_trylock()) + return restart_syscall(); + index = get_netdev_queue_index(queue); /* If queue belongs to subordinate dev use its TC mapping */ dev = netdev_get_tx_queue(dev, index)->sb_dev ? : dev; + num_tc = dev->num_tc; tc = netdev_txq_to_tc(dev, index); + + rtnl_unlock(); + if (tc < 0) return -EINVAL; @@ -1158,8 +1165,8 @@ static ssize_t traffic_class_show(struct netdev_queue *queue, * belongs to the root device it will be reported with just the * traffic class, so just "0" for TC 0 for example. */ - return dev->num_tc < 0 ? sprintf(buf, "%d%d\n", tc, dev->num_tc) : - sprintf(buf, "%d\n", tc); + return num_tc < 0 ? sprintf(buf, "%d%d\n", tc, num_tc) : + sprintf(buf, "%d\n", tc); } #ifdef CONFIG_XPS |