On Thu, Feb 18, 2016 at 09:56:22PM -0500, Sasha Levin wrote: > bpf_percpu_hash_update() expects rcu lock to be held and warns if it's not, > which pointed out a missing rcu read lock. > > Fixes: 15a07b338 ("bpf: add lookup/update support for per-cpu hash and array > maps") > Signed-off-by: Sasha Levin <sasha.le...@oracle.com> > --- > kernel/bpf/syscall.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c > index c95a753..94324b8 100644 > --- a/kernel/bpf/syscall.c > +++ b/kernel/bpf/syscall.c > @@ -348,7 +348,9 @@ static int map_update_elem(union bpf_attr *attr) > goto free_value; > > if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH) { > + rcu_read_lock(); > err = bpf_percpu_hash_update(map, key, value, attr->flags); > + rcu_read_unlock();
good catch. thanks, but could you add rcu_read_lock/unlock inside bpf_percpu_hash_update() instead... to match what bpf_percpu_hash_copy/bpf_percpu_array_update/bpf_percpu_array_copy are doing. Otherwise it's inconsistent.