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Subject[PATCH 5.5 163/367] bpf, devmap: Pass lockdep expression to RCU lists
From: Amol Grover <>

commit 485ec2ea9cf556e9c120e07961b7b459d776a115 upstream.

head is traversed using hlist_for_each_entry_rcu outside an RCU
read-side critical section but under the protection of dtab->index_lock.

Hence, add corresponding lockdep expression to silence false-positive
lockdep warnings, and harden RCU lists.

Fixes: 6f9d451ab1a3 ("xdp: Add devmap_hash map type for looking up devices by hashed index")
Signed-off-by: Amol Grover <>
Signed-off-by: Daniel Borkmann <>
Acked-by: Jesper Dangaard Brouer <>
Acked-by: Toke Høiland-Jørgensen <>
Signed-off-by: Greg Kroah-Hartman <>

kernel/bpf/devmap.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

--- a/kernel/bpf/devmap.c
+++ b/kernel/bpf/devmap.c
@@ -293,7 +293,8 @@ struct bpf_dtab_netdev *__dev_map_hash_l
struct hlist_head *head = dev_map_index_hash(dtab, key);
struct bpf_dtab_netdev *dev;

- hlist_for_each_entry_rcu(dev, head, index_hlist)
+ hlist_for_each_entry_rcu(dev, head, index_hlist,
+ lockdep_is_held(&dtab->index_lock))
if (dev->idx == key)
return dev;

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