[PATCH bpf] bpf: Reuse log from btf_prase_vmlinux() in btf_struct_ops_init()

[PATCH bpf] bpf: Reuse log from btf_prase_vmlinux() in btf_struct_ops_init()

[Martin KaFai Lau]

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: 27ae7997a661 ("bpf: Introduce BPF_PROG_TYPE_STRUCT_OPS")
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
---
 include/linux/bpf.h         | 7 +++++--
 kernel/bpf/bpf_struct_ops.c | 5 ++---
 kernel/bpf/btf.c            | 2 +-
 3 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 8e9ad3943cd9..49b1a70e12c8 100644
--- a/include/linux/bpf.h
+++ b/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);
diff --git a/kernel/bpf/bpf_struct_ops.c b/kernel/bpf/bpf_struct_ops.c
index 8ad1c9ea26b2..042f95534f86 100644
--- a/kernel/bpf/bpf_struct_ops.c
+++ b/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",
diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index b7c1660fb594..8c9d8f266bef 100644
--- a/kernel/bpf/btf.c
+++ b/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);
-- 
2.17.1

Re: [PATCH bpf] bpf: Reuse log from btf_prase_vmlinux() in btf_struct_ops_init()

[Andrii Nakryiko]

On Mon, Jan 27, 2020 at 9:52 AM Martin KaFai Lau <kafai@fb.com> wrote:
>
> 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: 27ae7997a661 ("bpf: Introduce BPF_PROG_TYPE_STRUCT_OPS")
> Signed-off-by: Martin KaFai Lau <kafai@fb.com>
> ---

LGTM, but there is typo in subject (btf_prase_vmlinux).

Acked-by: Andrii Nakryiko <andriin@fb.com>

[...]

Re: [PATCH bpf] bpf: Reuse log from btf_prase_vmlinux() in btf_struct_ops_init()

[Alexei Starovoitov]

On Mon, Jan 27, 2020 at 10:34 AM Andrii Nakryiko
<andrii.nakryiko@gmail.com> wrote:
>
> On Mon, Jan 27, 2020 at 9:52 AM Martin KaFai Lau <kafai@fb.com> wrote:
> >
> > 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: 27ae7997a661 ("bpf: Introduce BPF_PROG_TYPE_STRUCT_OPS")
> > Signed-off-by: Martin KaFai Lau <kafai@fb.com>
> > ---
>
> LGTM, but there is typo in subject (btf_prase_vmlinux).
>
> Acked-by: Andrii Nakryiko <andriin@fb.com>

Tested. All works.

Dave,
if you haven't sent PR yet may be you can apply this patch
directly to silence the warning?
Not a big deal if not. I don't see this warn with default config.

Acked-by: Alexei Starovoitov <ast@kernel.org>

Re: [PATCH bpf] bpf: Reuse log from btf_prase_vmlinux() in btf_struct_ops_init()

[Daniel Borkmann]

On 1/27/20 6:51 PM, Martin KaFai Lau wrote:
> 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: 27ae7997a661 ("bpf: Introduce BPF_PROG_TYPE_STRUCT_OPS")
> Signed-off-by: Martin KaFai Lau <kafai@fb.com>

Applied, thanks!