| From 485ec2ea9cf556e9c120e07961b7b459d776a115 Mon Sep 17 00:00:00 2001 |
| From: Amol Grover <frextrite@gmail.com> |
| Date: Thu, 23 Jan 2020 17:34:38 +0530 |
| Subject: bpf, devmap: Pass lockdep expression to RCU lists |
| MIME-Version: 1.0 |
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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; |
| |