| From | Greg Kroah-Hartman <> | Subject | [PATCH 5.5 163/367] bpf, devmap: Pass lockdep expression to RCU lists | Date | Mon, 10 Feb 2020 04:31:16 -0800 |
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From: Amol Grover <frextrite@gmail.com>
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 <frextrite@gmail.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Jesper Dangaard Brouer <brouer@redhat.com> Acked-by: Toke Høiland-Jørgensen <toke@redhat.com> Link: https://lore.kernel.org/bpf/20200123120437.26506-1-frextrite@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- 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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