From: Antoine Tenart atenart@kernel.org
[ 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: 184c449f91fe ("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 --- net/core/net-sysfs.c | 23 ++++++++++++++++++----- 1 file changed, 18 insertions(+), 5 deletions(-)
--- a/net/core/net-sysfs.c +++ b/net/core/net-sysfs.c @@ -1207,23 +1207,30 @@ static const struct attribute_group dql_ static ssize_t xps_cpus_show(struct netdev_queue *queue, char *buf) { + int cpu, len, ret, num_tc = 1, tc = 0; struct net_device *dev = queue->dev; - int cpu, len, num_tc = 1, tc = 0; struct xps_dev_maps *dev_maps; cpumask_var_t mask; unsigned long index;
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; + } }
- if (!zalloc_cpumask_var(&mask, GFP_KERNEL)) - return -ENOMEM; + if (!zalloc_cpumask_var(&mask, GFP_KERNEL)) { + ret = -ENOMEM; + goto err_rtnl_unlock; + }
rcu_read_lock(); dev_maps = rcu_dereference(dev->xps_maps); @@ -1246,9 +1253,15 @@ static ssize_t xps_cpus_show(struct netd } rcu_read_unlock();
+ rtnl_unlock(); + len = snprintf(buf, PAGE_SIZE, "%*pb\n", cpumask_pr_args(mask)); free_cpumask_var(mask); return len < PAGE_SIZE ? len : -EINVAL; + +err_rtnl_unlock: + rtnl_unlock(); + return ret; }
static ssize_t xps_cpus_store(struct netdev_queue *queue,