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authorJakub Kicinski <kuba@kernel.org>2025-03-24 15:45:31 -0700
committerJakub Kicinski <kuba@kernel.org>2025-03-25 10:06:49 -0700
commit0a65dcf6249b75c841b4218426b0d246a805c7e0 (patch)
tree11501e3fe35fdf79950fc41e3f0b5529df61a845 /net
parent4b702f8b72c7b05daa1b763fdc0840aa78178c3a (diff)
net: designate queue counts as "double ops protected" by instance lock
Drivers which opt into instance lock protection of ops should only call set_real_num_*_queues() under the instance lock. This means that queue counts are double protected (writes are under both rtnl_lock and instance lock, readers under either). Some readers may still be under the rtnl_lock, however, so for now we need double protection of writers. OTOH queue API paths are only under the protection of the instance lock, so we need to validate that the instance is actually locking ops, otherwise the input checks we do against queue count are racy. Acked-by: Stanislav Fomichev <sdf@fomichev.me> Link: https://patch.msgid.link/20250324224537.248800-6-kuba@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net')
-rw-r--r--net/core/dev.c2
-rw-r--r--net/core/net-sysfs.c2
-rw-r--r--net/core/netdev-genl.c7
-rw-r--r--net/core/netdev_rx_queue.c3
4 files changed, 14 insertions, 0 deletions
diff --git a/net/core/dev.c b/net/core/dev.c
index 6295f00e97a7..2d9be3ecd5e6 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -3130,6 +3130,7 @@ int netif_set_real_num_tx_queues(struct net_device *dev, unsigned int txq)
if (dev->reg_state == NETREG_REGISTERED ||
dev->reg_state == NETREG_UNREGISTERING) {
ASSERT_RTNL();
+ netdev_ops_assert_locked(dev);
rc = netdev_queue_update_kobjects(dev, dev->real_num_tx_queues,
txq);
@@ -3179,6 +3180,7 @@ int netif_set_real_num_rx_queues(struct net_device *dev, unsigned int rxq)
if (dev->reg_state == NETREG_REGISTERED) {
ASSERT_RTNL();
+ netdev_ops_assert_locked(dev);
rc = net_rx_queue_update_kobjects(dev, dev->real_num_rx_queues,
rxq);
diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c
index b6fbe629ccee..1ace0cd01adc 100644
--- a/net/core/net-sysfs.c
+++ b/net/core/net-sysfs.c
@@ -2148,8 +2148,10 @@ static void remove_queue_kobjects(struct net_device *dev)
net_rx_queue_update_kobjects(dev, real_rx, 0);
netdev_queue_update_kobjects(dev, real_tx, 0);
+ netdev_lock_ops(dev);
dev->real_num_rx_queues = 0;
dev->real_num_tx_queues = 0;
+ netdev_unlock_ops(dev);
#ifdef CONFIG_SYSFS
kset_unregister(dev->queues_kset);
#endif
diff --git a/net/core/netdev-genl.c b/net/core/netdev-genl.c
index 9e4882a22407..fd1cfa9707dc 100644
--- a/net/core/netdev-genl.c
+++ b/net/core/netdev-genl.c
@@ -867,6 +867,13 @@ int netdev_nl_bind_rx_doit(struct sk_buff *skb, struct genl_info *info)
goto err_unlock_sock;
}
+ if (!netdev_need_ops_lock(netdev)) {
+ err = -EOPNOTSUPP;
+ NL_SET_BAD_ATTR(info->extack,
+ info->attrs[NETDEV_A_DEV_IFINDEX]);
+ goto err_unlock;
+ }
+
if (dev_xdp_prog_count(netdev)) {
NL_SET_ERR_MSG(info->extack, "unable to bind dmabuf to device with XDP program attached");
err = -EEXIST;
diff --git a/net/core/netdev_rx_queue.c b/net/core/netdev_rx_queue.c
index a5b234b33cd5..3af716f77a13 100644
--- a/net/core/netdev_rx_queue.c
+++ b/net/core/netdev_rx_queue.c
@@ -92,6 +92,9 @@ static int __net_mp_open_rxq(struct net_device *dev, unsigned ifq_idx,
struct netdev_rx_queue *rxq;
int ret;
+ if (!netdev_need_ops_lock(dev))
+ return -EOPNOTSUPP;
+
if (ifq_idx >= dev->real_num_rx_queues)
return -EINVAL;
ifq_idx = array_index_nospec(ifq_idx, dev->real_num_rx_queues);