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Message-ID: <20240104130817.1221-1-yangtiezhu@loongson.cn>
Date: Thu, 4 Jan 2024 21:08:17 +0800
From: Tiezhu Yang <yangtiezhu@...ngson.cn>
To: Alexei Starovoitov <ast@...nel.org>,
Daniel Borkmann <daniel@...earbox.net>,
Andrii Nakryiko <andrii@...nel.org>
Cc: Eduard Zingerman <eddyz87@...il.com>,
bpf@...r.kernel.org,
linux-kernel@...r.kernel.org
Subject: [PATCH bpf-next v2] bpf: Return -ENOTSUPP if calls are not allowed in non-JITed programs
If CONFIG_BPF_JIT_ALWAYS_ON is not set and bpf_jit_enable is 0, there
exist 6 failed tests.
[root@...ux bpf]# echo 0 > /proc/sys/net/core/bpf_jit_enable
[root@...ux bpf]# echo 0 > /proc/sys/kernel/unprivileged_bpf_disabled
[root@...ux 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@...ux bpf]# echo 0 > /proc/sys/net/core/bpf_jit_enable
[root@...ux bpf]# echo 0 > /proc/sys/kernel/unprivileged_bpf_disabled
[root@...ux 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@...ngson.cn>
---
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;
}
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
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