diff options
| author | Martin KaFai Lau <martin.lau@kernel.org> | 2025-05-05 18:58:49 -0700 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2025-05-06 10:21:05 -0700 |
| commit | 7faccdf4b47d2c7674692aecdb5847da0f84dbd4 (patch) | |
| tree | 093191453836dcef715b7e060cf4316a5514188c /kernel/bpf | |
| parent | b183c0123d9ba16e147c990c02a9e6f37cac5df4 (diff) | |
bpf: Simplify reg0 marking for the rbtree kfuncs that return a bpf_rb_node pointer
The current rbtree kfunc, bpf_rbtree_{first, remove}, returns the
bpf_rb_node pointer. The check_kfunc_call currently checks the
kfunc btf_id instead of its return pointer type to decide
if it needs to do mark_reg_graph_node(reg0) and ref_set_non_owning(reg0).
The later patch will add bpf_rbtree_{root,left,right} that will also
return a bpf_rb_node pointer. Instead of adding more kfunc btf_id
checks to the "if" case, this patch changes the test to check the
kfunc's return type. is_rbtree_node_type() function is added to
test if a pointer type is a bpf_rb_node. The callers have already
skipped the modifiers of the pointer type.
A note on the ref_set_non_owning(), although bpf_rbtree_remove()
also returns a bpf_rb_node pointer, the bpf_rbtree_remove()
has the KF_ACQUIRE flag. Thus, its reg0 will not become non-owning.
Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20250506015857.817950-3-martin.lau@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'kernel/bpf')
| -rw-r--r-- | kernel/bpf/verifier.c | 10 |
1 files changed, 7 insertions, 3 deletions
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 2e1ce7debc16..bf14da00f09a 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -11987,6 +11987,11 @@ static bool is_kfunc_arg_res_spin_lock(const struct btf *btf, const struct btf_p return __is_kfunc_ptr_arg_type(btf, arg, KF_ARG_RES_SPIN_LOCK_ID); } +static bool is_rbtree_node_type(const struct btf_type *t) +{ + return t == btf_type_by_id(btf_vmlinux, kf_arg_btf_ids[KF_ARG_RB_NODE_ID]); +} + static bool is_kfunc_arg_callback(struct bpf_verifier_env *env, const struct btf *btf, const struct btf_param *arg) { @@ -13750,8 +13755,7 @@ static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn, struct btf_field *field = meta.arg_list_head.field; mark_reg_graph_node(regs, BPF_REG_0, &field->graph_root); - } else if (meta.func_id == special_kfunc_list[KF_bpf_rbtree_remove] || - meta.func_id == special_kfunc_list[KF_bpf_rbtree_first]) { + } else if (is_rbtree_node_type(ptr_type)) { struct btf_field *field = meta.arg_rbtree_root.field; mark_reg_graph_node(regs, BPF_REG_0, &field->graph_root); @@ -13881,7 +13885,7 @@ static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn, if (is_kfunc_ret_null(&meta)) regs[BPF_REG_0].id = id; regs[BPF_REG_0].ref_obj_id = id; - } else if (meta.func_id == special_kfunc_list[KF_bpf_rbtree_first]) { + } else if (is_rbtree_node_type(ptr_type)) { ref_set_non_owning(env, ®s[BPF_REG_0]); } |