From ab48c14a444b9198e91435526b68bfdf2613c2d0 Mon Sep 17 00:00:00 2001 From: Amol Grover Date: Thu, 23 Jan 2020 17:34:38 +0530 Subject: [PATCH] bpf, devmap: Pass lockdep expression to RCU lists MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Link: https://lore.kernel.org/bpf/20200123120437.26506-1-frextrite@gmail.com Signed-off-by: Greg Kroah-Hartman --- 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;