selftests/bpf: Skip callback tests if jit is disabled in test_verifier

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.

Add an explicit flag F_NEEDS_JIT_ENABLED to those tests to mark that they
require JIT enabled in bpf_loop_inline.c, check the flag and jit_disabled
at the beginning of do_test_single() to handle this case.

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

Suggested-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20240123090351.2207-3-yangtiezhu@loongson.cn

diff --git a/tools/testing/selftests/bpf/test_verifier.c b/tools/testing/selftests/bpf/test_verifier.c
index 1a09fc34d093a639844e16a098ac0e1f23703bd5..e1a1dfe8d7fac25af53d8b1edb8e512299b520c1 100644 (file)
--- a/tools/testing/selftests/bpf/test_verifier.c
+++ b/tools/testing/selftests/bpf/test_verifier.c
@@ -67,6 +67,7 @@
 
 #define F_NEEDS_EFFICIENT_UNALIGNED_ACCESS     (1 << 0)
 #define F_LOAD_WITH_STRICT_ALIGNMENT           (1 << 1)
+#define F_NEEDS_JIT_ENABLED                    (1 << 2)
 
 /* need CAP_BPF, CAP_NET_ADMIN, CAP_PERFMON to load progs */
 #define ADMIN_CAPS (1ULL << CAP_NET_ADMIN |    \
@@ -74,6 +75,7 @@
                    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;
@@ -1524,6 +1526,13 @@ static void do_test_single(struct bpf_test *test, bool unpriv,
        __u32 pflags;
        int i, err;
 
+       if ((test->flags & F_NEEDS_JIT_ENABLED) && jit_disabled) {
+               printf("SKIP (requires BPF JIT)");
+               skips++;
+               sched_yield();
+               return;
+       }
+
        fd_prog = -1;
        for (i = 0; i < MAX_NR_MAPS; i++)
                map_fds[i] = -1;
@@ -1844,6 +1853,8 @@ 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);
 

diff --git a/tools/testing/selftests/bpf/verifier/bpf_loop_inline.c b/tools/testing/selftests/bpf/verifier/bpf_loop_inline.c
index a535d41dc20d304a742e715b7b3867745ee30262..59125b22ae39a421cfc0d4369b6521b3b5dea103 100644 (file)
--- a/tools/testing/selftests/bpf/verifier/bpf_loop_inline.c
+++ b/tools/testing/selftests/bpf/verifier/bpf_loop_inline.c
@@ -57,6 +57,7 @@
        .expected_insns = { PSEUDO_CALL_INSN() },
        .unexpected_insns = { HELPER_CALL_INSN() },
        .prog_type = BPF_PROG_TYPE_TRACEPOINT,
+       .flags = F_NEEDS_JIT_ENABLED,
        .result = ACCEPT,
        .runs = 0,
        .func_info = { { 0, MAIN_TYPE }, { 12, CALLBACK_TYPE } },
@@ -90,6 +91,7 @@
        .expected_insns = { HELPER_CALL_INSN() },
        .unexpected_insns = { PSEUDO_CALL_INSN() },
        .prog_type = BPF_PROG_TYPE_TRACEPOINT,
+       .flags = F_NEEDS_JIT_ENABLED,
        .result = ACCEPT,
        .runs = 0,
        .func_info = { { 0, MAIN_TYPE }, { 16, CALLBACK_TYPE } },
@@ -127,6 +129,7 @@
        .expected_insns = { HELPER_CALL_INSN() },
        .unexpected_insns = { PSEUDO_CALL_INSN() },
        .prog_type = BPF_PROG_TYPE_TRACEPOINT,
+       .flags = F_NEEDS_JIT_ENABLED,
        .result = ACCEPT,
        .runs = 0,
        .func_info = {
@@ -165,6 +168,7 @@
        .expected_insns = { PSEUDO_CALL_INSN() },
        .unexpected_insns = { HELPER_CALL_INSN() },
        .prog_type = BPF_PROG_TYPE_TRACEPOINT,
+       .flags = F_NEEDS_JIT_ENABLED,
        .result = ACCEPT,
        .runs = 0,
        .func_info = {
@@ -235,6 +239,7 @@
        },
        .unexpected_insns = { HELPER_CALL_INSN() },
        .prog_type = BPF_PROG_TYPE_TRACEPOINT,
+       .flags = F_NEEDS_JIT_ENABLED,
        .result = ACCEPT,
        .func_info = {
                { 0, MAIN_TYPE },
@@ -252,6 +257,7 @@
        .unexpected_insns = { HELPER_CALL_INSN() },
        .result = ACCEPT,
        .prog_type = BPF_PROG_TYPE_TRACEPOINT,
+       .flags = F_NEEDS_JIT_ENABLED,
        .func_info = { { 0, MAIN_TYPE }, { 16, CALLBACK_TYPE } },
        .func_info_cnt = 2,
        BTF_TYPES