From: Kaitao Cheng <[email protected]> For the following scenario: struct tree_node { struct bpf_refcount ref; struct bpf_rb_node node; struct node_data __kptr * node_data; u64 key; }; This means node_data would have the type PTR_TO_BTF_ID | MEM_ALLOC | NON_OWN_REF | MEM_RCU.
When traversing an rbtree using bpf_rbtree_left/right, if we need to use bpf_kptr_xchg to read the __kptr pointer, we still need to follow the remove-read-add sequence. This patch allows us to use bpf_kptr_xchg to directly read the __kptr pointer without any prior operations. Signed-off-by: Kaitao Cheng <[email protected]> Signed-off-by: Feng Yang <[email protected]> --- kernel/bpf/verifier.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index bb3ff4bbb3a2..50cb4956e5bb 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -9261,7 +9261,8 @@ static const struct bpf_reg_types kptr_xchg_dest_types = { .types = { PTR_TO_MAP_VALUE, PTR_TO_BTF_ID | MEM_ALLOC, - PTR_TO_BTF_ID | MEM_ALLOC | NON_OWN_REF + PTR_TO_BTF_ID | MEM_ALLOC | NON_OWN_REF, + PTR_TO_BTF_ID | MEM_ALLOC | NON_OWN_REF | MEM_RCU } }; static const struct bpf_reg_types dynptr_types = { @@ -9422,6 +9423,7 @@ static int check_reg_type(struct bpf_verifier_env *env, u32 regno, case PTR_TO_BTF_ID | MEM_ALLOC: case PTR_TO_BTF_ID | MEM_PERCPU | MEM_ALLOC: case PTR_TO_BTF_ID | MEM_ALLOC | NON_OWN_REF: + case PTR_TO_BTF_ID | MEM_ALLOC | NON_OWN_REF | MEM_RCU: if (meta->func_id != BPF_FUNC_spin_lock && meta->func_id != BPF_FUNC_spin_unlock && meta->func_id != BPF_FUNC_kptr_xchg) { verifier_bug(env, "unimplemented handling of MEM_ALLOC"); -- 2.50.1 (Apple Git-155)
