Re: [PATCH] bpf: devmap: Pass lockdep expression to RCU lists
From: Amol Grover <hidden>
Date: 2020-01-23 17:18:12
Also in:
bpf, linux-kernel-mentees, lkml
On Thu, Jan 23, 2020 at 05:34:38PM +0530, Amol Grover wrote:
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")quoted hunk ↗ jump to hunk
Signed-off-by: Amol Grover <redacted> --- 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