bpf: Reuse log from btf_prase_vmlinux() in btf_struct_ops_init()

Instead of using a locally defined "struct bpf_verifier_log log = {}",
btf_struct_ops_init() should reuse the "log" from its calling
function "btf_parse_vmlinux()".  It should also resolve the
frame-size too large compiler warning in some ARCH.

Fixes: 27ae7997 ("bpf: Introduce BPF_PROG_TYPE_STRUCT_OPS")
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200127175145.1154438-1-kafai@fb.com

include/linux/bpf.h

@@ -728,7 +728,7 @@ struct bpf_struct_ops {
 #if defined(CONFIG_BPF_JIT) && defined(CONFIG_BPF_SYSCALL)
 #define BPF_MODULE_OWNER ((void *)((0xeB9FUL << 2) + POISON_POINTER_DELTA))
 const struct bpf_struct_ops *bpf_struct_ops_find(u32 type_id);
-void bpf_struct_ops_init(struct btf *btf);
+void bpf_struct_ops_init(struct btf *btf, struct bpf_verifier_log *log);
 bool bpf_struct_ops_get(const void *kdata);
 void bpf_struct_ops_put(const void *kdata);
 int bpf_struct_ops_map_sys_lookup_elem(struct bpf_map *map, void *key,
@@ -752,7 +752,10 @@ static inline const struct bpf_struct_ops *bpf_struct_ops_find(u32 type_id)
 {
 	return NULL;
 }
-static inline void bpf_struct_ops_init(struct btf *btf) { }
+static inline void bpf_struct_ops_init(struct btf *btf,
+				       struct bpf_verifier_log *log)
+{
+}
 static inline bool bpf_try_module_get(const void *data, struct module *owner)
 {
 	return try_module_get(owner);

kernel/bpf/bpf_struct_ops.c

@@ -96,12 +96,11 @@ const struct bpf_prog_ops bpf_struct_ops_prog_ops = {
 
 static const struct btf_type *module_type;
 
-void bpf_struct_ops_init(struct btf *btf)
+void bpf_struct_ops_init(struct btf *btf, struct bpf_verifier_log *log)
 {
 	s32 type_id, value_id, module_id;
 	const struct btf_member *member;
 	struct bpf_struct_ops *st_ops;
-	struct bpf_verifier_log log = {};
 	const struct btf_type *t;
 	char value_name[128];
 	const char *mname;
@@ -172,7 +171,7 @@ void bpf_struct_ops_init(struct btf *btf)
 							       member->type,
 							       NULL);
 			if (func_proto &&
-			    btf_distill_func_proto(&log, btf,
+			    btf_distill_func_proto(log, btf,
 						   func_proto, mname,
 						   &st_ops->func_models[j])) {
 				pr_warn("Error in parsing func ptr %s in struct %s\n",

kernel/bpf/btf.c

@@ -3643,7 +3643,7 @@ struct btf *btf_parse_vmlinux(void)
 		goto errout;
 	}
 
-	bpf_struct_ops_init(btf);
+	bpf_struct_ops_init(btf, log);
 
 	btf_verifier_env_free(env);
 	refcount_set(&btf->refcnt, 1);