From: Feng Zhou zhoufeng.zf@bytedance.com
After this commit: bpf: Support variable length array in tracing programs (9c5f8a1008a1) Trace programs can access variable length array, but for structure type. This patch adds support for integer type.
Example: Hook load_balance struct sched_domain { ... unsigned long span[]; }
The access: sd->span[0].
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 --- kernel/bpf/btf.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index 027f9f8a3551..a0887ee44e89 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -6157,11 +6157,13 @@ static int btf_struct_walk(struct bpf_verifier_log *log, const struct btf *btf, if (off < moff) goto error;
- /* Only allow structure for now, can be relaxed for - * other types later. - */ + /* allow structure and integer */ t = btf_type_skip_modifiers(btf, array_elem->type, NULL); + + if (btf_type_is_int(t)) + return WALK_SCALAR; + if (!btf_type_is_struct(t)) goto error;