[PATCH bpf-next v8] test_bpf: Add module parameter test_suite

From: Tiezhu Yang
Date: Wed Oct 27 2021 - 21:25:44 EST


After commit 9298e63eafea ("bpf/tests: Add exhaustive tests of ALU
operand magnitudes"), when modprobe test_bpf.ko with jit on mips64,
there exists segment fault due to the following reason:

ALU64_MOV_X: all register value magnitudes jited:1
Break instruction in kernel code[#1]

It seems that the related jit implementations of some test cases
in test_bpf() have problems. At this moment, I do not care about
the segment fault while I just want to verify the test cases of
tail calls.

Based on the above background and motivation, add the following
module parameter test_suite to the test_bpf.ko:
test_suite=<string>: only the specified test suite will be run, the
string can be "test_bpf", "test_tail_calls" or "test_skb_segment".

If test_suite is not specified, but test_id, test_name or test_range
is specified, set 'test_bpf' as the default test suite.

This is useful to only test the corresponding test suite when specify
the valid test_suite string.

Any invalid test suite will result in -EINVAL being returned and no
tests being run. If the test_suite is not specified or specified as
empty string, it does not change the current logic, all of the test
cases will be run.

Here are some test results:
# dmesg -c
# modprobe test_bpf
# dmesg | grep Summary
test_bpf: Summary: 1009 PASSED, 0 FAILED, [0/997 JIT'ed]
test_bpf: test_tail_calls: Summary: 8 PASSED, 0 FAILED, [0/8 JIT'ed]
test_bpf: test_skb_segment: Summary: 2 PASSED, 0 FAILED

# rmmod test_bpf
# dmesg -c
# modprobe test_bpf test_suite=test_bpf
# dmesg | tail -1
test_bpf: Summary: 1009 PASSED, 0 FAILED, [0/997 JIT'ed]

# rmmod test_bpf
# dmesg -c
# modprobe test_bpf test_suite=test_tail_calls
# dmesg
test_bpf: #0 Tail call leaf jited:0 21 PASS
[...]
test_bpf: #7 Tail call error path, index out of range jited:0 32 PASS
test_bpf: test_tail_calls: Summary: 8 PASSED, 0 FAILED, [0/8 JIT'ed]

# rmmod test_bpf
# dmesg -c
# modprobe test_bpf test_suite=test_skb_segment
# dmesg
test_bpf: #0 gso_with_rx_frags PASS
test_bpf: #1 gso_linear_no_head_frag PASS
test_bpf: test_skb_segment: Summary: 2 PASSED, 0 FAILED

# rmmod test_bpf
# dmesg -c
# modprobe test_bpf test_id=1
# dmesg
test_bpf: test_bpf: set 'test_bpf' as the default test_suite.
test_bpf: #1 TXA jited:0 54 51 50 PASS
test_bpf: Summary: 1 PASSED, 0 FAILED, [0/1 JIT'ed]

# rmmod test_bpf
# dmesg -c
# modprobe test_bpf test_suite=test_bpf test_name=TXA
# dmesg
test_bpf: #1 TXA jited:0 54 50 51 PASS
test_bpf: Summary: 1 PASSED, 0 FAILED, [0/1 JIT'ed]

# rmmod test_bpf
# dmesg -c
# modprobe test_bpf test_suite=test_tail_calls test_range=6,7
# dmesg
test_bpf: #6 Tail call error path, NULL target jited:0 41 PASS
test_bpf: #7 Tail call error path, index out of range jited:0 32 PASS
test_bpf: test_tail_calls: Summary: 2 PASSED, 0 FAILED, [0/2 JIT'ed]

# rmmod test_bpf
# dmesg -c
# modprobe test_bpf test_suite=test_skb_segment test_id=1
# dmesg
test_bpf: #1 gso_linear_no_head_frag PASS
test_bpf: test_skb_segment: Summary: 1 PASSED, 0 FAILED

By the way, the above segment fault has been fixed in the latest bpf-next
tree.

Signed-off-by: Tiezhu Yang <yangtiezhu@xxxxxxxxxxx>
Acked-by: Johan Almbladh <johan.almbladh@xxxxxxxxxxxxxxxxx>
Tested-by: Johan Almbladh <johan.almbladh@xxxxxxxxxxxxxxxxx>
---

v8:
-- Use strscpy(test_suite, "test_bpf", sizeof(test_suite))
instead of strcpy, suggested by Johan Almbladh, thank you.

v7:
-- Rename prepare_bpf_tests() to prepare_test_range(), remove
some unnecessary code, suggested by Johan Almbladh, thank you.

v6:
-- Compute the valid range once in the beginning of prepare_bpf_tests(),
suggested by Johan Almbladh, thank you.

v5:
-- Remove some duplicated code, suggested by Johan Almbladh,
thank you.
-- Initialize test_range[2] to {0, INT_MAX}.
-- If test_suite is specified, but test_range is not specified,
set the upper limit of each test_suite to overwrite INT_MAX.

v4:
-- Fix the following checkpatch issues:
CHECK: Alignment should match open parenthesis
CHECK: Please don't use multiple blank lines

./scripts/checkpatch.pl --strict *.patch
total: 0 errors, 0 warnings, 0 checks, 299 lines checked

the default max-line-length is 100 in ./scripts/checkpatch.pl,
but it seems that the netdev/checkpatch is 80:
https://patchwork.hopto.org/static/nipa/559961/12545157/checkpatch/stdout

v3:
-- Use test_suite instead of test_type as module parameter
-- Make test_id, test_name and test_range selection applied to each test suite

v2:
-- Fix typo in the commit message
-- Use my private email to send

lib/test_bpf.c | 212 ++++++++++++++++++++++++++++++++++++---------------------
1 file changed, 135 insertions(+), 77 deletions(-)

diff --git a/lib/test_bpf.c b/lib/test_bpf.c
index e5b10fd..adae395 100644
--- a/lib/test_bpf.c
+++ b/lib/test_bpf.c
@@ -14316,72 +14316,9 @@ module_param_string(test_name, test_name, sizeof(test_name), 0);
static int test_id = -1;
module_param(test_id, int, 0);

-static int test_range[2] = { 0, ARRAY_SIZE(tests) - 1 };
+static int test_range[2] = { 0, INT_MAX };
module_param_array(test_range, int, NULL, 0);

-static __init int find_test_index(const char *test_name)
-{
- int i;
-
- for (i = 0; i < ARRAY_SIZE(tests); i++) {
- if (!strcmp(tests[i].descr, test_name))
- return i;
- }
- return -1;
-}
-
-static __init int prepare_bpf_tests(void)
-{
- if (test_id >= 0) {
- /*
- * if a test_id was specified, use test_range to
- * cover only that test.
- */
- if (test_id >= ARRAY_SIZE(tests)) {
- pr_err("test_bpf: invalid test_id specified.\n");
- return -EINVAL;
- }
-
- test_range[0] = test_id;
- test_range[1] = test_id;
- } else if (*test_name) {
- /*
- * if a test_name was specified, find it and setup
- * test_range to cover only that test.
- */
- int idx = find_test_index(test_name);
-
- if (idx < 0) {
- pr_err("test_bpf: no test named '%s' found.\n",
- test_name);
- return -EINVAL;
- }
- test_range[0] = idx;
- test_range[1] = idx;
- } else {
- /*
- * check that the supplied test_range is valid.
- */
- if (test_range[0] >= ARRAY_SIZE(tests) ||
- test_range[1] >= ARRAY_SIZE(tests) ||
- test_range[0] < 0 || test_range[1] < 0) {
- pr_err("test_bpf: test_range is out of bound.\n");
- return -EINVAL;
- }
-
- if (test_range[1] < test_range[0]) {
- pr_err("test_bpf: test_range is ending before it starts.\n");
- return -EINVAL;
- }
- }
-
- return 0;
-}
-
-static __init void destroy_bpf_tests(void)
-{
-}
-
static bool exclude_test(int test_id)
{
return test_id < test_range[0] || test_id > test_range[1];
@@ -14553,6 +14490,10 @@ static __init int test_skb_segment(void)
for (i = 0; i < ARRAY_SIZE(skb_segment_tests); i++) {
const struct skb_segment_test *test = &skb_segment_tests[i];

+ cond_resched();
+ if (exclude_test(i))
+ continue;
+
pr_info("#%d %s ", i, test->descr);

if (test_skb_segment_single(test)) {
@@ -14934,6 +14875,8 @@ static __init int test_tail_calls(struct bpf_array *progs)
int ret;

cond_resched();
+ if (exclude_test(i))
+ continue;

pr_info("#%d %s ", i, test->descr);
if (!fp) {
@@ -14966,29 +14909,144 @@ static __init int test_tail_calls(struct bpf_array *progs)
return err_cnt ? -EINVAL : 0;
}

+static char test_suite[32];
+module_param_string(test_suite, test_suite, sizeof(test_suite), 0);
+
+static __init int find_test_index(const char *test_name)
+{
+ int i;
+
+ if (!strcmp(test_suite, "test_bpf")) {
+ for (i = 0; i < ARRAY_SIZE(tests); i++) {
+ if (!strcmp(tests[i].descr, test_name))
+ return i;
+ }
+ }
+
+ if (!strcmp(test_suite, "test_tail_calls")) {
+ for (i = 0; i < ARRAY_SIZE(tail_call_tests); i++) {
+ if (!strcmp(tail_call_tests[i].descr, test_name))
+ return i;
+ }
+ }
+
+ if (!strcmp(test_suite, "test_skb_segment")) {
+ for (i = 0; i < ARRAY_SIZE(skb_segment_tests); i++) {
+ if (!strcmp(skb_segment_tests[i].descr, test_name))
+ return i;
+ }
+ }
+
+ return -1;
+}
+
+static __init int prepare_test_range(void)
+{
+ int valid_range;
+
+ if (!strcmp(test_suite, "test_bpf"))
+ valid_range = ARRAY_SIZE(tests);
+ else if (!strcmp(test_suite, "test_tail_calls"))
+ valid_range = ARRAY_SIZE(tail_call_tests);
+ else if (!strcmp(test_suite, "test_skb_segment"))
+ valid_range = ARRAY_SIZE(skb_segment_tests);
+ else
+ return 0;
+
+ if (test_id >= 0) {
+ /*
+ * if a test_id was specified, use test_range to
+ * cover only that test.
+ */
+ if (test_id >= valid_range) {
+ pr_err("test_bpf: invalid test_id specified for '%s' suite.\n",
+ test_suite);
+ return -EINVAL;
+ }
+
+ test_range[0] = test_id;
+ test_range[1] = test_id;
+ } else if (*test_name) {
+ /*
+ * if a test_name was specified, find it and setup
+ * test_range to cover only that test.
+ */
+ int idx = find_test_index(test_name);
+
+ if (idx < 0) {
+ pr_err("test_bpf: no test named '%s' found for '%s' suite.\n",
+ test_name, test_suite);
+ return -EINVAL;
+ }
+ test_range[0] = idx;
+ test_range[1] = idx;
+ } else if (test_range[0] != 0 || test_range[1] != INT_MAX) {
+ /*
+ * check that the supplied test_range is valid.
+ */
+ if (test_range[0] < 0 || test_range[1] >= valid_range) {
+ pr_err("test_bpf: test_range is out of bound for '%s' suite.\n",
+ test_suite);
+ return -EINVAL;
+ }
+
+ if (test_range[1] < test_range[0]) {
+ pr_err("test_bpf: test_range is ending before it starts.\n");
+ return -EINVAL;
+ }
+ }
+
+ return 0;
+}
+
static int __init test_bpf_init(void)
{
struct bpf_array *progs = NULL;
int ret;

- ret = prepare_bpf_tests();
+ if (strlen(test_suite) &&
+ strcmp(test_suite, "test_bpf") &&
+ strcmp(test_suite, "test_tail_calls") &&
+ strcmp(test_suite, "test_skb_segment")) {
+ pr_err("test_bpf: invalid test_suite '%s' specified.\n", test_suite);
+ return -EINVAL;
+ }
+
+ /*
+ * if test_suite is not specified, but test_id, test_name or test_range
+ * is specified, set 'test_bpf' as the default test suite.
+ */
+ if (!strlen(test_suite) &&
+ (test_id != -1 || strlen(test_name) ||
+ (test_range[0] != 0 || test_range[1] != INT_MAX))) {
+ pr_info("test_bpf: set 'test_bpf' as the default test_suite.\n");
+ strscpy(test_suite, "test_bpf", sizeof(test_suite));
+ }
+
+ ret = prepare_test_range();
if (ret < 0)
return ret;

- ret = test_bpf();
- destroy_bpf_tests();
- if (ret)
- return ret;
+ if (!strlen(test_suite) || !strcmp(test_suite, "test_bpf")) {
+ ret = test_bpf();
+ if (ret)
+ return ret;
+ }

- ret = prepare_tail_call_tests(&progs);
- if (ret)
- return ret;
- ret = test_tail_calls(progs);
- destroy_tail_call_tests(progs);
- if (ret)
- return ret;
+ if (!strlen(test_suite) || !strcmp(test_suite, "test_tail_calls")) {
+ ret = prepare_tail_call_tests(&progs);
+ if (ret)
+ return ret;
+ ret = test_tail_calls(progs);
+ destroy_tail_call_tests(progs);
+ if (ret)
+ return ret;
+ }

- return test_skb_segment();
+ if (!strlen(test_suite) || !strcmp(test_suite, "test_skb_segment"))
+ return test_skb_segment();
+
+ return 0;
}

static void __exit test_bpf_exit(void)
--
2.1.0