On Thu, 23 Jan 2020 17:34:38 +0530 Amol Grover <frextrite@xxxxxxxxx> 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. We do hold the lock in update and delete cases, but not in the lookup cases. Is it then still okay to add the lockdep_is_held() annotation? If it is then it looks fine to me: Acked-by: Jesper Dangaard Brouer <brouer@xxxxxxxxxx> > Hence, add corresponding lockdep expression to silence false-positive > lockdep warnings, and harden RCU lists. > > Signed-off-by: Amol Grover <frextrite@xxxxxxxxx> > --- > 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; > -- Best regards, Jesper Dangaard Brouer MSc.CS, Principal Kernel Engineer at Red Hat LinkedIn: http://www.linkedin.com/in/brouer
