On Thu, Jan 04, 2024 at 09:08:17PM +0800, Tiezhu Yang wrote:
> If CONFIG_BPF_JIT_ALWAYS_ON is not set and bpf_jit_enable is 0, there
> exist 6 failed tests.
>
> [root@linux bpf]# echo 0 > /proc/sys/net/core/bpf_jit_enable
> [root@linux bpf]# echo 0 > /proc/sys/kernel/unprivileged_bpf_disabled
> [root@linux bpf]# ./test_verifier | grep FAIL
> #106/p inline simple bpf_loop call FAIL
> #107/p don't inline bpf_loop call, flags non-zero FAIL
> #108/p don't inline bpf_loop call, callback non-constant FAIL
> #109/p bpf_loop_inline and a dead func FAIL
> #110/p bpf_loop_inline stack locations for loop vars FAIL
> #111/p inline bpf_loop call in a big program FAIL
> Summary: 768 PASSED, 15 SKIPPED, 6 FAILED
>
> The test log shows that callbacks are not allowed in non-JITed programs,
> interpreter doesn't support them yet, thus these tests should be skipped
> if jit is disabled, just return -ENOTSUPP instead of -EINVAL for pseudo
> calls in fixup_call_args().
>
> With this patch:
>
> [root@linux bpf]# echo 0 > /proc/sys/net/core/bpf_jit_enable
> [root@linux bpf]# echo 0 > /proc/sys/kernel/unprivileged_bpf_disabled
> [root@linux bpf]# ./test_verifier | grep FAIL
> Summary: 768 PASSED, 21 SKIPPED, 0 FAILED
>
> Additionally, as Eduard suggested, return -ENOTSUPP instead of -EINVAL
> for the other three places where "non-JITed" is used in error messages
> to keep consistent.
>
> Signed-off-by: Tiezhu Yang <yangtiezhu@xxxxxxxxxxx>
> ---
>
> v2:
> -- rebase on the latest bpf-next tree.
> -- return -ENOTSUPP instead of -EINVAL for the other three places
> where "non-JITed" is used in error messages to keep consistent.
> -- update the patch subject and commit message.
>
> kernel/bpf/verifier.c | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
> index d5f4ff1eb235..99558a5186b2 100644
> --- a/kernel/bpf/verifier.c
> +++ b/kernel/bpf/verifier.c
> @@ -8908,7 +8908,7 @@ static int check_map_func_compatibility(struct bpf_verifier_env *env,
> goto error;
> if (env->subprog_cnt > 1 && !allow_tail_call_in_subprogs(env)) {
> verbose(env, "tail_calls are not allowed in non-JITed programs with bpf-to-bpf calls\n");
> - return -EINVAL;
> + return -ENOTSUPP;
FWIW I agree with John review earlier [1], also there's chance (however small)
we could mess up with some app already checking on that
jirka
[1] https://lore.kernel.org/bpf/6594a4c15a677_11e86208cd@john.notmuch/
> }
> break;
> case BPF_FUNC_perf_event_read:
> @@ -19069,14 +19069,14 @@ static int fixup_call_args(struct bpf_verifier_env *env)
> #ifndef CONFIG_BPF_JIT_ALWAYS_ON
> if (has_kfunc_call) {
> verbose(env, "calling kernel functions are not allowed in non-JITed programs\n");
> - return -EINVAL;
> + return -ENOTSUPP;
> }
> if (env->subprog_cnt > 1 && env->prog->aux->tail_call_reachable) {
> /* When JIT fails the progs with bpf2bpf calls and tail_calls
> * have to be rejected, since interpreter doesn't support them yet.
> */
> verbose(env, "tail_calls are not allowed in non-JITed programs with bpf-to-bpf calls\n");
> - return -EINVAL;
> + return -ENOTSUPP;
> }
> for (i = 0; i < prog->len; i++, insn++) {
> if (bpf_pseudo_func(insn)) {
> @@ -19084,7 +19084,7 @@ static int fixup_call_args(struct bpf_verifier_env *env)
> * have to be rejected, since interpreter doesn't support them yet.
> */
> verbose(env, "callbacks are not allowed in non-JITed programs\n");
> - return -EINVAL;
> + return -ENOTSUPP;
> }
>
> if (!bpf_pseudo_call(insn))
> --
> 2.42.0
>
>
