# \[PATCH bpf-next v5 5/7\] net: core: Allow netdev\_lower\_get\_next\_private\_rcu in bh context

- From: Jussi Maki \<hidden\>
- Date: 2021-08-04 12:46:20 
- List: netdev
- Page: https://ratatoskr.run/netdev/2021/08/7775729
- Thread: https://ratatoskr.run/bpf/2021/06/7771994/t.md

```text
For the XDP bonding slave lookup to work in the NAPI poll context
in which the redudant rcu_read_lock() has been removed we have to
follow the same approach as in [1] and modify the WARN_ON to also
check rcu_read_lock_bh_held().

[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=694cea395fded425008e93cd90cfdf7a451674af

Signed-off-by: Jussi Maki <redacted>
---
 net/core/dev.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/core/dev.c b/net/core/dev.c
index 27023ea933dd..ae1aecf97b58 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -7588,7 +7588,7 @@ void *netdev_lower_get_next_private_rcu(struct net_device *dev,
 {
 	struct netdev_adjacent *lower;
 
-	WARN_ON_ONCE(!rcu_read_lock_held());
+	WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_bh_held());
 
 	lower = list_entry_rcu((*iter)->next, struct netdev_adjacent, list);
 
-- 
2.17.1

```