On Thu, 2024-02-01 at 04:21 +0000, Kumar Kartikeya Dwivedi wrote:
[...]
> +static int adjust_subprog_frame_descs_after_remove(struct bpf_verifier_env *env, u32 off, u32 cnt)
> +{
> + for (int i = 0; i < env->subprog_cnt; i++) {
> + struct bpf_exception_frame_desc_tab *fdtab = subprog_info(env, i)->fdtab;
> +
> + if (!fdtab)
> + continue;
> + for (int j = 0; j < fdtab->cnt; j++) {
> + /* Part of a subprog_info whose instructions were removed partially, but the fdtab remained. */
> + if (fdtab->desc[j]->pc >= off && fdtab->desc[j]->pc < off + cnt) {
> + void *p = fdtab->desc[j];
> + if (j < fdtab->cnt - 1)
> + memmove(fdtab->desc + j, fdtab->desc + j + 1, sizeof(fdtab->desc[0]) * (fdtab->cnt - j - 1));
> + kfree(p);
Is it necessary to release btf references for desc entries that are removed?
Those that were grabbed by add_used_btf() in gen_exception_frame_desc_iter_entry().
> + fdtab->cnt--;
> + j--;
> + }
> + if (fdtab->desc[j]->pc >= off + cnt)
> + fdtab->desc[j]->pc -= cnt;
> + }
> + }
> + return 0;
> +}
> +
[...]
