From: Feng Zhou <zhoufeng.zf@xxxxxxxxxxxxx>
[ Upstream commit 91f2dc6838c19342f7f2993627c622835cc24890 ]
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 bb6728d75611 ("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: bb6728d75611 ("bpf: Allow access to int pointer arguments in tracing programs")
Co-developed-by: Chengming Zhou <zhouchengming@xxxxxxxxxxxxx>
Signed-off-by: Chengming Zhou <zhouchengming@xxxxxxxxxxxxx>
Signed-off-by: Feng Zhou <zhoufeng.zf@xxxxxxxxxxxxx>
Signed-off-by: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
Acked-by: Jiri Olsa <jolsa@xxxxxxxxxx>
Link: https://lore.kernel.org/bpf/20230410085908.98493-2-zhoufeng.zf@xxxxxxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
kernel/bpf/btf.c | 8 ++------
1 file changed, 2 insertions(+), 6 deletions(-)
diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index 70ab572f81bc7..7f18d48c4a15b 100644
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -5848,12 +5848,8 @@ 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);
}
--
2.39.2
