Commit 91f2dc68 authored Apr 10, 2023 by Feng Zhou Committed by Daniel Borkmann Apr 11, 2023

bpf/btf: Fix is_int_ptr()

When tracing a kernel function with arg type is u32*, btf_ctx_access()
would report error: arg2 type INT is not a struct.

The commit bb6728d7 ("bpf: Allow access to int pointer arguments
in tracing programs") added support for int pointer, but did not skip
modifiers before checking it's type. This patch fixes it.

Fixes: bb6728d7 ("bpf: Allow access to int pointer arguments in tracing programs")
Co-developed-by: Chengming Zhou <zhouchengming@bytedance.com>
Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
Signed-off-by: Feng Zhou <zhoufeng.zf@bytedance.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/bpf/20230410085908.98493-2-zhoufeng.zf@bytedance.com

parent 255f0e14

kernel/bpf/btf.c

+2 −6

Original line number	Diff line number	Diff line
		@@ -5921,12 +5921,8 @@ struct btf bpf_prog_get_target_btf(const struct bpf_prog prog)

		static bool is_int_ptr(struct btf btf, const struct btf_type t)
		{
		/* t comes in already as a pointer */
		t = btf_type_by_id(btf, t->type);

		/* allow const */
		if (BTF_INFO_KIND(t->info) == BTF_KIND_CONST)
		t = btf_type_by_id(btf, t->type);
		/* skip modifiers */
		t = btf_type_skip_modifiers(btf, t->type, NULL);

		return btf_type_is_int(t);
		}