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Subject[PATCH] bpf: devmap: Pass lockdep expression to RCU lists
Date
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.

Signed-off-by: Amol Grover <frextrite@gmail.com>
---
kernel/bpf/devmap.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/bpf/devmap.c b/kernel/bpf/devmap.c
index 3d3d61b5985b..b4b6b77f309c 100644
--- a/kernel/bpf/devmap.c
+++ b/kernel/bpf/devmap.c
@@ -293,7 +293,8 @@ struct bpf_dtab_netdev *__dev_map_hash_lookup_elem(struct bpf_map *map, u32 key)
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;

--
2.24.1
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