[PATCH bpf-next v4 2/2] selftests/bpf: Skip callback tests if jit is disabled in test_verifier

Tiezhu Yang posted 2 patches 1 year, 11 months ago
There is a newer version of this series
[PATCH bpf-next v4 2/2] selftests/bpf: Skip callback tests if jit is disabled in test_verifier
Posted by Tiezhu Yang 1 year, 11 months ago
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, copy some check functions from the other places under
tools directory, and then handle this case in do_test_single().

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

Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
---
 tools/testing/selftests/bpf/test_verifier.c | 23 +++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/tools/testing/selftests/bpf/test_verifier.c b/tools/testing/selftests/bpf/test_verifier.c
index 1a09fc34d093..02c4a0bbdc5e 100644
--- a/tools/testing/selftests/bpf/test_verifier.c
+++ b/tools/testing/selftests/bpf/test_verifier.c
@@ -74,6 +74,7 @@
 		    1ULL << CAP_BPF)
 #define UNPRIV_SYSCTL "kernel/unprivileged_bpf_disabled"
 static bool unpriv_disabled = false;
+static bool jit_disabled;
 static int skips;
 static bool verbose = false;
 static int verif_log_level = 0;
@@ -1355,6 +1356,16 @@ static bool is_skip_insn(struct bpf_insn *insn)
 	return memcmp(insn, &skip_insn, sizeof(skip_insn)) == 0;
 }
 
+static bool is_ldimm64_insn(struct bpf_insn *insn)
+{
+	return insn->code == (BPF_LD | BPF_IMM | BPF_DW);
+}
+
+static bool insn_is_pseudo_func(struct bpf_insn *insn)
+{
+	return is_ldimm64_insn(insn) && insn->src_reg == BPF_PSEUDO_FUNC;
+}
+
 static int null_terminated_insn_len(struct bpf_insn *seq, int max_len)
 {
 	int i;
@@ -1622,6 +1633,16 @@ static void do_test_single(struct bpf_test *test, bool unpriv,
 	alignment_prevented_execution = 0;
 
 	if (expected_ret == ACCEPT || expected_ret == VERBOSE_ACCEPT) {
+		if (fd_prog < 0 && saved_errno == EINVAL && jit_disabled) {
+			for (i = 0; i < prog_len; i++, prog++) {
+				if (!insn_is_pseudo_func(prog))
+					continue;
+				printf("SKIP (callbacks are not allowed in non-JITed programs)\n");
+				skips++;
+				goto close_fds;
+			}
+		}
+
 		if (fd_prog < 0) {
 			printf("FAIL\nFailed to load prog '%s'!\n",
 			       strerror(saved_errno));
@@ -1844,6 +1865,8 @@ int main(int argc, char **argv)
 		return EXIT_FAILURE;
 	}
 
+	jit_disabled = !is_jit_enabled();
+
 	/* Use libbpf 1.0 API mode */
 	libbpf_set_strict_mode(LIBBPF_STRICT_ALL);
 
-- 
2.42.0
Re: [PATCH bpf-next v4 2/2] selftests/bpf: Skip callback tests if jit is disabled in test_verifier
Posted by Song Liu 1 year, 11 months ago
On Mon, Jan 15, 2024 at 8:50 PM Tiezhu Yang <yangtiezhu@loongson.cn> 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, copy some check functions from the other places under
> tools directory, and then handle this case in do_test_single().
>
> 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
>
> Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
> ---
>  tools/testing/selftests/bpf/test_verifier.c | 23 +++++++++++++++++++++
>  1 file changed, 23 insertions(+)
>
> diff --git a/tools/testing/selftests/bpf/test_verifier.c b/tools/testing/selftests/bpf/test_verifier.c
> index 1a09fc34d093..02c4a0bbdc5e 100644
> --- a/tools/testing/selftests/bpf/test_verifier.c
> +++ b/tools/testing/selftests/bpf/test_verifier.c
> @@ -74,6 +74,7 @@
>                     1ULL << CAP_BPF)
>  #define UNPRIV_SYSCTL "kernel/unprivileged_bpf_disabled"
>  static bool unpriv_disabled = false;
> +static bool jit_disabled;
>  static int skips;
>  static bool verbose = false;
>  static int verif_log_level = 0;
> @@ -1355,6 +1356,16 @@ static bool is_skip_insn(struct bpf_insn *insn)
>         return memcmp(insn, &skip_insn, sizeof(skip_insn)) == 0;
>  }
>
> +static bool is_ldimm64_insn(struct bpf_insn *insn)
> +{
> +       return insn->code == (BPF_LD | BPF_IMM | BPF_DW);
> +}
> +
> +static bool insn_is_pseudo_func(struct bpf_insn *insn)
> +{
> +       return is_ldimm64_insn(insn) && insn->src_reg == BPF_PSEUDO_FUNC;
> +}
> +

These two functions are duplicated from libbpf_internal.h and libbpf.c.
It will be good to reuse them. We will need something like the following
to include libbpf_internal.h and fix "poisoned" errors.

Thanks,
Song

diff --git i/tools/testing/selftests/bpf/test_verifier.c
w/tools/testing/selftests/bpf/test_verifier.c
index 98107e0452d3..7528a6b41623 100644
--- i/tools/testing/selftests/bpf/test_verifier.c
+++ w/tools/testing/selftests/bpf/test_verifier.c
@@ -41,6 +41,7 @@
 #include "test_btf.h"
 #include "../../../include/linux/filter.h"
 #include "testing_helpers.h"
+#include "bpf/libbpf_internal.h"

 #ifndef ENOTSUPP
 #define ENOTSUPP 524
@@ -1143,8 +1144,8 @@ static void do_test_fixup(struct bpf_test *test,
enum bpf_prog_type prog_type,
                } while (*fixup_map_xskmap);
        }
        if (*fixup_map_stacktrace) {
-               map_fds[12] = create_map(BPF_MAP_TYPE_STACK_TRACE, sizeof(u32),
-                                        sizeof(u64), 1);
+               map_fds[12] = create_map(BPF_MAP_TYPE_STACK_TRACE,
sizeof(__u32),
+                                        sizeof(__u64), 1);
                do {
                        prog[*fixup_map_stacktrace].imm = map_fds[12];
                        fixup_map_stacktrace++;
@@ -1203,7 +1204,7 @@ static void do_test_fixup(struct bpf_test *test,
enum bpf_prog_type prog_type,
        }
        if (*fixup_map_reuseport_array) {
                map_fds[19] = __create_map(BPF_MAP_TYPE_REUSEPORT_SOCKARRAY,
-                                          sizeof(u32), sizeof(u64), 1, 0);
+                                          sizeof(__u32), sizeof(__u64), 1, 0);
                do {
                        prog[*fixup_map_reuseport_array].imm = map_fds[19];
                        fixup_map_reuseport_array++;
Re: [PATCH bpf-next v4 2/2] selftests/bpf: Skip callback tests if jit is disabled in test_verifier
Posted by Hou Tao 1 year, 11 months ago

On 1/16/2024 12:50 PM, 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, copy some check functions from the other places under
> tools directory, and then handle this case in do_test_single().
>
> 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
>
> Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>

Acked-by: Hou Tao <houtao1@huawei.com>