bpf: Do not allow map_freeze in struct_ops map

struct_ops map cannot support map_freeze. Otherwise, a struct_ops cannot be unregistered from the subsystem. Fixes: 85d33df ("bpf: Introduce BPF_MAP_TYPE_STRUCT_OPS") Signed-off-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20200305013454.535397-1-kafai@fb.com
mariux64 · Mar 5, 2020 · 849b4d9 · 849b4d9
1 parent 8e5290e
commit 849b4d9
Showing 1 changed file with 5 additions and 0 deletions.
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
@@ -1510,6 +1510,11 @@ static int map_freeze(const union bpf_attr *attr)
 	if (IS_ERR(map))
 		return PTR_ERR(map);
 
+	if (map->map_type == BPF_MAP_TYPE_STRUCT_OPS) {
+		fdput(f);
+		return -ENOTSUPP;
+	}
+
 	mutex_lock(&map->freeze_mutex);
 
 	if (map->writecnt) {