Re: [PATCH v2 2/6] kunit: kunit-test: Add test cases for extending log buffer

From: Rae Moar
Date: Tue Aug 08 2023 - 17:18:55 EST

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On Tue, Aug 8, 2023 at 8:35 AM Richard Fitzgerald
<rf@xxxxxxxxxxxxxxxxxxxxx> wrote:
>
> Add test cases for the dynamically-extending log buffer.
>
> kunit_log_extend_test_1() logs a series of numbered lines then tests
> that the resulting log contains all the lines.
>
> kunit_log_extend_test_2() logs a large number of lines of varying length
> to create many fragments, then tests that all lines are present.
>
> kunit_log_frag_sized_line_test() logs a line that exactly fills a
> fragment. This should not cause an extension of the log or truncation
> of the line.
>
> kunit_log_newline_test() has a new test to append a line that is exactly
> the length of the available space in the current fragment and check that
> the resulting log has a trailing '\n'.
>
> Signed-off-by: Richard Fitzgerald <rf@xxxxxxxxxxxxxxxxxxxxx>

Hello!

I am happy to see so many tests in this patch series. I've been
working with these patches and the debugfs logs seem to be working
well.

However, when I ran the new kunit-log-test tests three of the tests
failed: kunit_log_extend_test_1(), kunit_log_extend_test_2(), and
kunit_log_newline_test().

The diagnostic info for kunit_log_extend_test_1() reports:

[20:55:27] # kunit_log_extend_test_1: EXPECTATION FAILED at
lib/kunit/kunit-test.c:705
[20:55:27] Expected p == line, but
[20:55:27] p == "xxxxxx…xxxx12345678"
[20:55:27] line == "The quick brown fox jumps over the lazy penguin 0"
…
[20:55:27] # kunit_log_extend_test_1: EXPECTATION FAILED at
lib/kunit/kunit-test.c:705
[20:55:27] Expected p == line, but
[20:55:27] p == "The quick brown fox jumps over the lazy penguin 1"
[20:55:27] line == "The quick brown fox jumps over the lazy penguin 4"
[20:55:27] # kunit_log_extend_test_1: EXPECTATION FAILED at
lib/kunit/kunit-test.c:705
[20:55:27] Expected p == line, but
[20:55:27] p == "The quick brown fox jumps over the lazy penguin 2"
[20:55:27] line == "The quick brown fox jumps over the lazy penguin 5"
…
[20:55:27] # kunit_log_extend_test_1: EXPECTATION FAILED at
lib/kunit/kunit-test.c:709
[20:55:27] Expected i == num_lines, but
[20:55:27] i == 64 (0x40)
[20:55:27] num_lines == 141 (0x8d)

So it looks like the log contains a different number of lines than
expected which is causing the difference of 3 between expected and
what was obtained. Potentially the log is not getting cleared/freed
properly in between test cases?

The diagnostic info for kunit_log_extend_test_2() reports:

[20:55:27] # kunit_log_extend_test_2: EXPECTATION FAILED at
lib/kunit/kunit-test.c:776
[20:55:27] Expected p == &line[i], but
[20:55:27] p ==
"xxxxx...xxxxx123456780123456789abcdef101112131415161718191a1b1c1d1e1f202122232425262728292a2b2c2d2e2f30313233343536373839"
[20:55:27] &line[i] ==
"0123456789abcdef101112131415161718191a1b1c1d1e1f202122232425262728292a2b2c2d2e2f30313233343536373839"
[20:55:27] # kunit_log_extend_test_2: EXPECTATION FAILED at
lib/kunit/kunit-test.c:781
[20:55:27] Expected n == num_lines, but
[20:55:27] n == 147 (0x93)
[20:55:27] num_lines == 155 (0x9b)
[20:55:27] Not enough lines.

Similar difference in the number of lines here.

The diagnostic info for kunit_log_newline_test() reports that the test
fails on this line:

KUNIT_EXPECT_EQ(test, p[strlen(p) - 1], '\n');

Let me know if you are seeing similar errors. I can post the full log
if that would be helpful.

-Rae

> ---
> lib/kunit/kunit-test.c | 204 +++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 204 insertions(+)
>
> diff --git a/lib/kunit/kunit-test.c b/lib/kunit/kunit-test.c
> index 54dc011c8980..48967d12e053 100644
> --- a/lib/kunit/kunit-test.c
> +++ b/lib/kunit/kunit-test.c
> @@ -7,6 +7,7 @@
> */
> #include <kunit/test.h>
> #include <kunit/test-bug.h>
> +#include <linux/prandom.h>
>
> #include "try-catch-impl.h"
>
> @@ -530,6 +531,31 @@ static struct kunit_suite kunit_resource_test_suite = {
> .test_cases = kunit_resource_test_cases,
> };
>
> +static char *get_concatenated_log(struct kunit *test, const struct list_head *log,
> + int *num_frags)
> +{
> + struct kunit_log_frag *frag;
> + size_t len = 0;
> + int frag_count = 0;
> + char *p;
> +
> + list_for_each_entry(frag, log, list)
> + len += strlen(frag->buf);
> +
> + len++; /* for terminating '\0' */
> + p = kunit_kmalloc(test, len, GFP_KERNEL);
> +
> + list_for_each_entry(frag, log, list) {
> + strlcat(p, frag->buf, len);
> + ++frag_count;
> + }
> +
> + if (num_frags)
> + *num_frags = frag_count;
> +
> + return p;
> +}
> +
> static void kunit_log_test(struct kunit *test)
> {
> struct kunit_suite suite;
> @@ -568,7 +594,9 @@ static void kunit_log_test(struct kunit *test)
>
> static void kunit_log_newline_test(struct kunit *test)
> {
> + struct kunit_suite suite;
> struct kunit_log_frag *frag;
> + char *p;
>
> kunit_info(test, "Add newline\n");
> if (test->log) {
> @@ -576,14 +604,190 @@ static void kunit_log_newline_test(struct kunit *test)
> KUNIT_ASSERT_NOT_NULL_MSG(test, strstr(frag->buf, "Add newline\n"),
> "Missing log line, full log:\n%s", frag->buf);
> KUNIT_EXPECT_NULL(test, strstr(frag->buf, "Add newline\n\n"));
> +
> + suite.log = kunit_kzalloc(test, sizeof(*suite.log), GFP_KERNEL);
> + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, suite.log);
> + INIT_LIST_HEAD(suite.log);
> + frag = kunit_kmalloc(test, sizeof(*frag), GFP_KERNEL);
> + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, frag);
> + kunit_init_log_frag(frag);
> + list_add_tail(&frag->list, suite.log);
> +
> + /* String that exactly fills fragment leaving no room for \n */
> + memset(frag->buf, 0, sizeof(frag->buf));
> + memset(frag->buf, 'x', sizeof(frag->buf) - 9);
> + kunit_log_append(suite.log, "12345678");
> + p = get_concatenated_log(test, suite.log, NULL);
> + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, p);
> + KUNIT_EXPECT_NOT_NULL_MSG(test, strstr(p, "x12345678\n"),
> + "Newline not appended when fragment is full. Log is:\n'%s'", p);
> } else {
> kunit_skip(test, "only useful when debugfs is enabled");
> }
> }
>
> +static void kunit_log_extend_test_1(struct kunit *test)
> +{
> +#ifdef CONFIG_KUNIT_DEBUGFS
> + struct kunit_suite suite;
> + struct kunit_log_frag *frag;
> + char line[60];
> + char *p, *pn;
> + size_t len, n;
> + int num_lines, num_frags, i;
> +
> + suite.log = kunit_kzalloc(test, sizeof(*suite.log), GFP_KERNEL);
> + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, suite.log);
> + INIT_LIST_HEAD(suite.log);
> + frag = kunit_kmalloc(test, sizeof(*frag), GFP_KERNEL);
> + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, frag);
> + kunit_init_log_frag(frag);
> + KUNIT_EXPECT_EQ(test, frag->buf[0], '\0');
> + list_add_tail(&frag->list, suite.log);
> +
> + i = 0;
> + len = 0;
> + do {
> + n = snprintf(line, sizeof(line),
> + "The quick brown fox jumps over the lazy penguin %d\n", i);
> + KUNIT_ASSERT_LT(test, n, sizeof(line));
> + kunit_log_append(suite.log, line);
> + ++i;
> + len += n;
> + } while (len < (sizeof(frag->buf) * 30));
> + num_lines = i;
> +
> + p = get_concatenated_log(test, suite.log, &num_frags);
> + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, p);
> + KUNIT_EXPECT_GT(test, num_frags, 1);
> +
> + kunit_info(test, "num lines:%d num_frags:%d total len:%zu\n",
> + num_lines, num_frags, strlen(p));
> +
> + i = 0;
> + while ((pn = strchr(p, '\n')) != NULL) {
> + *pn = '\0';
> + snprintf(line, sizeof(line),
> + "The quick brown fox jumps over the lazy penguin %d", i);
> + KUNIT_EXPECT_STREQ(test, p, line);
> + p = pn + 1;
> + ++i;
> + }
> + KUNIT_EXPECT_EQ(test, i, num_lines);
> +#else
> + kunit_skip(test, "only useful when debugfs is enabled");
> +#endif
> +}
> +
> +static void kunit_log_extend_test_2(struct kunit *test)
> +{
> +#ifdef CONFIG_KUNIT_DEBUGFS
> + struct kunit_suite suite;
> + struct kunit_log_frag *frag;
> + struct rnd_state rnd;
> + char line[101];
> + char *p, *pn;
> + size_t len;
> + int num_lines, num_frags, n, i;
> +
> + suite.log = kunit_kzalloc(test, sizeof(*suite.log), GFP_KERNEL);
> + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, suite.log);
> + INIT_LIST_HEAD(suite.log);
> + frag = kunit_kmalloc(test, sizeof(*frag), GFP_KERNEL);
> + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, frag);
> + kunit_init_log_frag(frag);
> + KUNIT_EXPECT_EQ(test, frag->buf[0], '\0');
> + list_add_tail(&frag->list, suite.log);
> +
> + /* Build log line of varying content */
> + line[0] = '\0';
> + i = 0;
> + do {
> + char tmp[9];
> +
> + snprintf(tmp, sizeof(tmp), "%x", i++);
> + len = strlcat(line, tmp, sizeof(line));
> + } while (len < sizeof(line) - 1);
> +
> + /*
> + * Log lines of different lengths until we have created
> + * many fragments.
> + * The "randomness" must be repeatable.
> + */
> + prandom_seed_state(&rnd, 3141592653589793238ULL);
> + i = 0;
> + len = 0;
> + num_lines = 0;
> + do {
> + kunit_log_append(suite.log, "%s\n", &line[i]);
> + len += sizeof(line) - i;
> + num_lines++;
> + i = prandom_u32_state(&rnd) % (sizeof(line) - 1);
> + } while (len < (sizeof(frag->buf) * 30));
> +
> + /* There must be more than one buffer fragment now */
> + KUNIT_EXPECT_FALSE(test, list_is_singular(suite.log));
> +
> + p = get_concatenated_log(test, suite.log, &num_frags);
> + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, p);
> + KUNIT_EXPECT_GT(test, num_frags, 1);
> +
> + kunit_info(test, "num lines:%d num_frags:%d total len:%zu\n",
> + num_lines, num_frags, strlen(p));
> +
> + prandom_seed_state(&rnd, 3141592653589793238ULL);
> + i = 0;
> + n = 0;
> + while ((pn = strchr(p, '\n')) != NULL) {
> + *pn = '\0';
> + KUNIT_EXPECT_STREQ(test, p, &line[i]);
> + p = pn + 1;
> + n++;
> + i = prandom_u32_state(&rnd) % (sizeof(line) - 1);
> + }
> + KUNIT_EXPECT_EQ_MSG(test, n, num_lines, "Not enough lines.");
> +#else
> + kunit_skip(test, "only useful when debugfs is enabled");
> +#endif
> +}
> +
> +static void kunit_log_frag_sized_line_test(struct kunit *test)
> +{
> +#ifdef CONFIG_KUNIT_DEBUGFS
> + struct kunit_suite suite;
> + struct kunit_log_frag *frag, *src;
> +
> + suite.log = kunit_kzalloc(test, sizeof(*suite.log), GFP_KERNEL);
> + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, suite.log);
> + INIT_LIST_HEAD(suite.log);
> + frag = kunit_kmalloc(test, sizeof(*frag), GFP_KERNEL);
> + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, frag);
> + kunit_init_log_frag(frag);
> + KUNIT_EXPECT_EQ(test, frag->buf[0], '\0');
> + list_add_tail(&frag->list, suite.log);
> +
> + src = kunit_kzalloc(test, sizeof(*src), GFP_KERNEL);
> + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, src);
> + memset(src->buf, 'x', sizeof(src->buf) - 2);
> + KUNIT_ASSERT_EQ(test, strlen(src->buf), sizeof(src->buf) - 2);
> +
> + /* Log a string that exactly fills the fragment */
> + kunit_log_append(suite.log, "%s\n", src->buf);
> + KUNIT_EXPECT_TRUE(test, list_is_singular(suite.log));
> + KUNIT_EXPECT_EQ(test, strlen(frag->buf), sizeof(frag->buf) - 1);
> + strlcat(src->buf, "\n", sizeof(src->buf));
> + KUNIT_EXPECT_STREQ(test, frag->buf, src->buf);
> +#else
> + kunit_skip(test, "only useful when debugfs is enabled");
> +#endif
> +}
> +
> static struct kunit_case kunit_log_test_cases[] = {
> KUNIT_CASE(kunit_log_test),
> KUNIT_CASE(kunit_log_newline_test),
> + KUNIT_CASE(kunit_log_extend_test_1),
> + KUNIT_CASE(kunit_log_extend_test_2),
> + KUNIT_CASE(kunit_log_frag_sized_line_test),
> {}
> };
>
> --
> 2.30.2
>

Next message: Kees Cook: "[GIT PULL] hardening fixes for v6.5-rc6"
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In reply to: Richard Fitzgerald: "[PATCH v2 2/6] kunit: kunit-test: Add test cases for extending log buffer"
Next in thread: Richard Fitzgerald: "Re: [PATCH v2 2/6] kunit: kunit-test: Add test cases for extending log buffer"
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