Re: [PATCH v4 3/3] kunit: fix bug of extra newline characters in debugfs logs

On Thu, 9 Mar 2023 at 04:40, Rae Moar rmoar@google.com wrote:

Fix bug of the extra newline characters in debugfs logs. When a line is added to debugfs with a newline character at the end, an extra line appears in the debugfs log.

This is due to a discrepancy between how the lines are printed and how they are added to the logs. Remove this discrepancy by checking if a newline character is present before adding a newline character. This should closely match the printk behavior.

Add kunit_log_newline_test to provide test coverage for this issue. (Also, move kunit_log_test above suite definition to remove the unnecessary declaration prior to the suite definition)

As an example, say we add these two lines to the log:

kunit_log(..., "KTAP version 1\n"); kunit_log(..., "1..1");

The debugfs log before this fix:

KTAP version 1

1..1

The debugfs log after this fix:

KTAP version 1 1..1

Signed-off-by: Rae Moar rmoar@google.com Reviewed-by: David Gow davidgow@google.com

---

Changes from v3 -> v4:

• Slight formatting change in test.h regarding "" placement.

Thanks. This series looks good-to-go to me now!

Cheers, -- David

Changes from v2 -> v3:

• Changes to commit message.

Changes from v1 -> v2:

• Changed the way extra newlines are removed. Instead of removing extra newline characters, add a newline if one is not present. This is a bit cleaner.
• Note: I looked into using KERN_CONT to match the printk behavior to vsnprintf but this could cause issues with KTAP printing on the same line as interrupting kernel messages. I also looked at just adding KERN_CONT functionality to kunit_log and I did get this to work but it was a bit messy because it required a few calls to kunit_log_newline in kunit_run_tests. If this is very desired functionality, happy to add this to version 3.

include/kunit/test.h | 2 +- lib/kunit/kunit-test.c | 35 +++++++++++++++++++++++------------ lib/kunit/test.c | 18 ++++++++++++++++++ 3 files changed, 42 insertions(+), 13 deletions(-)

diff --git a/include/kunit/test.h b/include/kunit/test.h index 0668d29f3453..9721584027d8 100644 --- a/include/kunit/test.h +++ b/include/kunit/test.h @@ -420,7 +420,7 @@ void __printf(2, 3) kunit_log_append(char *log, const char *fmt, ...); #define kunit_log(lvl, test_or_suite, fmt, ...) \ do { \ printk(lvl fmt, ##__VA_ARGS__); \

•           kunit_log_append((test_or_suite)->log,  fmt "\n",       \
  

•           kunit_log_append((test_or_suite)->log,  fmt,            \
                             ##__VA_ARGS__);                        \
    } while (0)
  
  

diff --git a/lib/kunit/kunit-test.c b/lib/kunit/kunit-test.c index 4df0335d0d06..b63595d3e241 100644 --- a/lib/kunit/kunit-test.c +++ b/lib/kunit/kunit-test.c @@ -443,18 +443,6 @@ static struct kunit_suite kunit_resource_test_suite = { .test_cases = kunit_resource_test_cases, };

-static void kunit_log_test(struct kunit *test);

-static struct kunit_case kunit_log_test_cases[] = {

•   KUNIT_CASE(kunit_log_test),
  

•   {}
  

-};

-static struct kunit_suite kunit_log_test_suite = {

•   .name = "kunit-log-test",
  

•   .test_cases = kunit_log_test_cases,
  

-};

static void kunit_log_test(struct kunit *test) { struct kunit_suite suite; @@ -481,6 +469,29 @@ static void kunit_log_test(struct kunit *test) #endif }

+static void kunit_log_newline_test(struct kunit *test) +{

•   kunit_info(test, "Add newline\n");
  

•   if (test->log) {
  

•           KUNIT_ASSERT_NOT_NULL_MSG(test, strstr(test->log, "Add newline\n"),
  

•                   "Missing log line, full log:\n%s", test->log);
  

•           KUNIT_EXPECT_NULL(test, strstr(test->log, "Add newline\n\n"));
  

•   } else {
  

•           kunit_skip(test, "only useful when debugfs is enabled");
  

•   }
  

+}

+static struct kunit_case kunit_log_test_cases[] = {

•   KUNIT_CASE(kunit_log_test),
  

•   KUNIT_CASE(kunit_log_newline_test),
  

•   {}
  

+};

+static struct kunit_suite kunit_log_test_suite = {

•   .name = "kunit-log-test",
  

•   .test_cases = kunit_log_test_cases,
  

+};

static void kunit_status_set_failure_test(struct kunit *test) { struct kunit fake; diff --git a/lib/kunit/test.c b/lib/kunit/test.c index 811fcc376d2f..e2910b261112 100644 --- a/lib/kunit/test.c +++ b/lib/kunit/test.c @@ -108,6 +108,22 @@ static void kunit_print_test_stats(struct kunit *test, stats.total); }

+/**

• • kunit_log_newline() - Add newline to the end of log if one is not
• • already present.
• • @log: The log to add the newline to.
• */

+static void kunit_log_newline(char *log) +{

•   int log_len, len_left;
  

•   log_len = strlen(log);
  

•   len_left = KUNIT_LOG_SIZE - log_len - 1;
  

•   if (log_len > 0 && log[log_len - 1] != '\n')
  

•           strncat(log, "\n", len_left);
  

+}

/*

• Append formatted message to log, size of which is limited to
• KUNIT_LOG_SIZE bytes (including null terminating byte).

@@ -135,6 +151,8 @@ void kunit_log_append(char *log, const char *fmt, ...) vsnprintf(log + log_len, min(len, len_left), fmt, args); va_end(args);

•   /* Add newline to end of log if not already present. */
  

•   kunit_log_newline(log);
  

} EXPORT_SYMBOL_GPL(kunit_log_append);

-- 2.40.0.rc0.216.gc4246ad0f0-goog