[PATCH AUTOSEL 6.3 18/59] netdev: Enforce index cap in netdev_get_tx_queue

[Sasha Levin]

From: Nick Child <nnac123@xxxxxxxxxxxxx>

[ Upstream commit 1cc6571f562774f1d928dc8b3cff50829b86e970 ]

When requesting a TX queue at a given index, warn on out-of-bounds
referencing if the index is greater than the allocated number of
queues.

Specifically, since this function is used heavily in the networking
stack use DEBUG_NET_WARN_ON_ONCE to avoid executing a new branch on
every packet.

Signed-off-by: Nick Child <nnac123@xxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20230321150725.127229-2-nnac123@xxxxxxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 include/linux/netdevice.h | 1 +
 1 file changed, 1 insertion(+)

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index c35f04f636f15..7db9f960221d3 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -2463,6 +2463,7 @@ static inline
 struct netdev_queue *netdev_get_tx_queue(const struct net_device *dev,
 					 unsigned int index)
 {
+	DEBUG_NET_WARN_ON_ONCE(index >= dev->num_tx_queues);
 	return &dev->_tx[index];
 }
 
-- 
2.39.2