[PATCH bpf-next v3 2/9] bpf: Assign reg->id when getting referenced kptr from ctx

Amery Hung
2026-04-21T22:10:21Z

Assign reg->id when getting referenced kptr from read program context
to be consistent with R0 of KF_ACQUIRE kfunc. skb dynptr will track the
referenced skb in qdisc programs using a new field reg->parent_id in
a later patch.

Signed-off-by: Amery Hung <ameryhung@gmail.com>
---
kernel/bpf/verifier.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 41e4ea41c72e..93003a2a96b0 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -6448,8 +6448,6 @@ static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, u32 regn
} else {
mark_reg_known_zero(env, regs,
value_regno);
- if (type_may_be_null(info.reg_type))
- regs[value_regno].id = ++env->id_gen;
/* A load of ctx field could have different
* actual load size with the one encoded in the
* insn. When the dst is PTR, it is for sure not
@@ -6459,8 +6457,11 @@ static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, u32 regn
if (base_type(info.reg_type) == PTR_TO_BTF_ID) {
regs[value_regno].btf = info.btf;
regs[value_regno].btf_id = info.btf_id;
+ regs[value_regno].id = info.ref_obj_id;
regs[value_regno].ref_obj_id = info.ref_obj_id;
}
+ if (type_may_be_null(info.reg_type) && !regs[value_regno].id)
+ regs[value_regno].id = ++env->id_gen;
}
regs[value_regno].type = info.reg_type;
}
--
2.52.0