On Thu, 2024-02-01 at 04:20 +0000, Kumar Kartikeya Dwivedi wrote:
[...]
> +static int mark_exception_reachable_subprogs(struct bpf_verifier_env *env)
> +{
[...]
> +restart:
> + subprog_end = subprog[idx + 1].start;
> + for (; i < subprog_end; i++) {
[...]
> + if (!bpf_pseudo_call(insn + i) && !bpf_pseudo_func(insn + i))
> + continue;
> + /* remember insn and function to return to */
> + ret_insn[frame] = i + 1;
> + ret_prog[frame] = idx;
> +
> + /* find the callee */
> + next_insn = i + insn[i].imm + 1;
> + sidx = find_subprog(env, next_insn);
> + if (sidx < 0) {
> + WARN_ONCE(1, "verifier bug. No program starts at insn %d\n", next_insn);
> + return -EFAULT;
> + }
For programs like:
foo():
bar()
bar()
this algorithm would scan bar() multiple times.
Would it be possible to remember if subprogram had been scanned
already and reuse collected .is_throw_reachable info?
[...]
