[PATCH net] net: Lock netdevices during dev_shutdown

[PATCH net] net: Lock netdevices during dev_shutdown

[Cosmin Ratiu]

__qdisc_destroy() calls into various qdiscs .destroy() op, which in turn
can call .ndo_setup_tc(), which requires the netdev instance lock.

This commit extends the critical section in
unregister_netdevice_many_notify() to cover dev_shutdown() (and
dev_tcx_uninstall() as a side-effect) and acquires the netdev instance
lock in __dev_change_net_namespace() for the other dev_shutdown() call.

This should now guarantee that for all qdisc ops, the netdev instance
lock is held during .ndo_setup_tc().

Fixes: a0527ee2df3f ("net: hold netdev instance lock during qdisc ndo_setup_tc")
Signed-off-by: Cosmin Ratiu <cratiu@nvidia.com>
---
 net/core/dev.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/net/core/dev.c b/net/core/dev.c
index 1be7cb73a602..92e004c354ea 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -11966,9 +11966,9 @@ void unregister_netdevice_many_notify(struct list_head *head,
 		struct sk_buff *skb = NULL;
 
 		/* Shutdown queueing discipline. */
+		netdev_lock_ops(dev);
 		dev_shutdown(dev);
 		dev_tcx_uninstall(dev);
-		netdev_lock_ops(dev);
 		dev_xdp_uninstall(dev);
 		dev_memory_provider_uninstall(dev);
 		netdev_unlock_ops(dev);
@@ -12161,7 +12161,9 @@ int __dev_change_net_namespace(struct net_device *dev, struct net *net,
 	synchronize_net();
 
 	/* Shutdown queueing discipline. */
+	netdev_lock_ops(dev);
 	dev_shutdown(dev);
+	netdev_unlock_ops(dev);
 
 	/* Notify protocols, that we are about to destroy
 	 * this device. They should clean all the things.
-- 
2.45.0

Re: [PATCH net] net: Lock netdevices during dev_shutdown

[Stanislav Fomichev]

On 05/05, Cosmin Ratiu wrote:
> __qdisc_destroy() calls into various qdiscs .destroy() op, which in turn
> can call .ndo_setup_tc(), which requires the netdev instance lock.
> 
> This commit extends the critical section in
> unregister_netdevice_many_notify() to cover dev_shutdown() (and
> dev_tcx_uninstall() as a side-effect) and acquires the netdev instance
> lock in __dev_change_net_namespace() for the other dev_shutdown() call.
> 
> This should now guarantee that for all qdisc ops, the netdev instance
> lock is held during .ndo_setup_tc().
> 
> Fixes: a0527ee2df3f ("net: hold netdev instance lock during qdisc ndo_setup_tc")
> Signed-off-by: Cosmin Ratiu <cratiu@nvidia.com>

Acked-by: Stanislav Fomichev <sdf@fomichev.me>

Thanks!

Re: [PATCH net] net: Lock netdevices during dev_shutdown

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net.git (main)
by Jakub Kicinski <kuba@kernel.org>:

On Mon, 5 May 2025 22:47:13 +0300 you wrote:
> __qdisc_destroy() calls into various qdiscs .destroy() op, which in turn
> can call .ndo_setup_tc(), which requires the netdev instance lock.
> 
> This commit extends the critical section in
> unregister_netdevice_many_notify() to cover dev_shutdown() (and
> dev_tcx_uninstall() as a side-effect) and acquires the netdev instance
> lock in __dev_change_net_namespace() for the other dev_shutdown() call.
> 
> [...]

Here is the summary with links:
  - [net] net: Lock netdevices during dev_shutdown
    https://git.kernel.org/netdev/net/c/08e9f2d584c4

You are awesome, thank you!
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