On Tue, Nov 23, 2021 at 10:02 PM Alexei Starovoitov
<alexei.starovoitov@xxxxxxxxx> wrote:
> +
> + /* Attempt to find target candidates in vmlinux BTF first */
> + main_btf = bpf_get_btf_vmlinux();
> + cands = bpf_core_add_cands(cands, main_btf, 1);
> + if (IS_ERR(cands))
> + return cands;
> +
> + /* populate cache even when cands->cnt == 0 */
> + populate_cand_cache(cands, vmlinux_cand_cache, VMLINUX_CAND_CACHE_SIZE);
> +
> + /* if vmlinux BTF has any candidate, don't go for module BTFs */
> + if (cands->cnt)
> + return cands;
> +
> +check_modules:
> + cc = check_cand_cache(cands, module_cand_cache, MODULE_CAND_CACHE_SIZE);
> + if (cc) {
> + bpf_free_cands(cands);
> + /* if cache has it return it even if cc->cnt == 0 */
> + return cc;
> + }
Found another issue in the above: When cache is populated
with empty cands the above free_cands() will make it uaf.
Fixing in respin.
