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

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[ Upstream commit fb25038586d0064123e393cadf1fadd70a9df97a ]

Accesses to dev->xps_cpus_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: 184c449f91 ("net: Add support for XPS with QoS via traffic classes")
Signed-off-by: Antoine Tenart <atenart@kernel.org>
Reviewed-by: Alexander Duyck <alexanderduyck@fb.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Antoine Tenart 2020-12-23 22:23:21 +01:00 committed by Greg Kroah-Hartman
parent 4da25d83b7
commit 0ca897c1ec
1 changed files with 22 additions and 7 deletions
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29
net/core/net-sysfs.c
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@ -1317,8 +1317,8 @@ static const struct attribute_group dql_group = {
static ssize_t xps_cpus_show(struct netdev_queue *queue, static ssize_t xps_cpus_show(struct netdev_queue *queue,
char *buf) char *buf)
{ {
int cpu, len, ret, num_tc = 1, tc = 0;
struct net_device *dev = queue->dev; struct net_device *dev = queue->dev;
int cpu, len, num_tc = 1, tc = 0;
struct xps_dev_maps *dev_maps; struct xps_dev_maps *dev_maps;
cpumask_var_t mask; cpumask_var_t mask;
unsigned long index; unsigned long index;
@ -1328,22 +1328,31 @@ static ssize_t xps_cpus_show(struct netdev_queue *queue,
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) {
/* Do not allow XPS on subordinate device directly */ /* Do not allow XPS on subordinate device directly */
num_tc = dev->num_tc; num_tc = dev->num_tc;
if (num_tc < 0) if (num_tc < 0) {
return -EINVAL; ret = -EINVAL;
goto err_rtnl_unlock;
}
/* If queue belongs to subordinate dev use its map */ /* If queue belongs to subordinate dev use its map */
dev = netdev_get_tx_queue(dev, index)->sb_dev ? : dev; dev = netdev_get_tx_queue(dev, index)->sb_dev ? : dev;
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;
}
} }
if (!zalloc_cpumask_var(&mask, GFP_KERNEL)) if (!zalloc_cpumask_var(&mask, GFP_KERNEL)) {
return -ENOMEM; ret = -ENOMEM;
goto err_rtnl_unlock;
}
rcu_read_lock(); rcu_read_lock();
dev_maps = rcu_dereference(dev->xps_cpus_map); dev_maps = rcu_dereference(dev->xps_cpus_map);
@ -1366,9 +1375,15 @@ static ssize_t xps_cpus_show(struct netdev_queue *queue,
} }
rcu_read_unlock(); rcu_read_unlock();
rtnl_unlock();
len = snprintf(buf, PAGE_SIZE, "%*pb\n", cpumask_pr_args(mask)); len = snprintf(buf, PAGE_SIZE, "%*pb\n", cpumask_pr_args(mask));
free_cpumask_var(mask); free_cpumask_var(mask);
return len < PAGE_SIZE ? len : -EINVAL; return len < PAGE_SIZE ? len : -EINVAL;
err_rtnl_unlock:
rtnl_unlock();
return ret;
} }
static ssize_t xps_cpus_store(struct netdev_queue *queue, static ssize_t xps_cpus_store(struct netdev_queue *queue,