On Wed, Aug 9, 2023 at 11:54 AM Richard Fitzgerald rf@opensource.cirrus.com wrote:

Re-implement the log buffer as a list of buffer fragments that can be extended as the size of the log info grows.

When using parameterization the test case can run many times and create a large amount of log. It's not really practical to keep increasing the size of the fixed buffer every time a test needs more space. And a big fixed buffer wastes memory.

The original char *log pointer is replaced by a pointer to a list of struct kunit_log_frag, each containing a fixed-size buffer.

kunit_log_append() now attempts to append to the last kunit_log_frag in the list. If there isn't enough space it will append a new kunit_log_frag to the list. This simple implementation does not attempt to completely fill the buffer in every kunit_log_frag.

The 'log' member of kunit_suite, kunit_test_case and kunit_suite must be a pointer because the API of kunit_log() requires that is the same type in all three structs. As kunit.log is a pointer to the 'log' of the current kunit_case, it must be a pointer in the other two structs.

The existing kunit-test.c log tests have been updated to build against the new fragmented log implementation. If the test fails the new function get_concatenated_log() constructs a single contiguous string from the log fragments so that the whole log can be emitted in the failure message.

Hello!

All the tests now pass for me and this patch now looks good to me. I have tested it and it seems to be working well.

I just have a few nits below. But I am overall happy with this patch.

Reviewed-by: Rae Moar rmoar@google.com

-Rae

Signed-off-by: Richard Fitzgerald rf@opensource.cirrus.com

include/kunit/test.h | 25 +++++++++++----- lib/kunit/debugfs.c | 65 ++++++++++++++++++++++++++++++++++-------- lib/kunit/kunit-test.c | 48 +++++++++++++++++++++++++------ lib/kunit/test.c | 63 ++++++++++++++++++++++++++++------------ 4 files changed, 155 insertions(+), 46 deletions(-)

diff --git a/include/kunit/test.h b/include/kunit/test.h index d33114097d0d..cb5082efc91c 100644 --- a/include/kunit/test.h +++ b/include/kunit/test.h @@ -33,8 +33,8 @@ DECLARE_STATIC_KEY_FALSE(kunit_running);

struct kunit;

-/* Size of log associated with test. */ -#define KUNIT_LOG_SIZE 2048 +/* Size of log buffer fragments. */ +#define KUNIT_LOG_FRAGMENT_SIZE (256 - sizeof(struct list_head))

/* Maximum size of parameter description string. */ #define KUNIT_PARAM_DESC_SIZE 128 @@ -85,6 +85,17 @@ struct kunit_attributes { enum kunit_speed speed; };

+struct kunit_log_frag {

•   struct list_head list;
  

•   char buf[KUNIT_LOG_FRAGMENT_SIZE];
  

+};

+static inline void kunit_init_log_frag(struct kunit_log_frag *frag) +{

•   INIT_LIST_HEAD(&frag->list);
  

•   frag->buf[0] = '\0';
  

+}

/**

• struct kunit_case - represents an individual test case.

@@ -132,7 +143,7 @@ struct kunit_case { /* private: internal use only. */ enum kunit_status status; char *module_name;

•   char *log;
  

•   struct list_head *log;
  

};

static inline char *kunit_status_to_ok_not_ok(enum kunit_status status) @@ -252,7 +263,7 @@ struct kunit_suite { /* private: internal use only */ char status_comment[KUNIT_STATUS_COMMENT_SIZE]; struct dentry *debugfs;

•   char *log;
  

•   struct list_head *log;
    int suite_init_err;
  

};

@@ -278,7 +289,7 @@ struct kunit {

    /* private: internal use only. */
    const char *name; /* Read only after initialization! */

•   char *log; /* Points at case log after initialization */
  

•   struct list_head *log; /* Points at case log after initialization */
  

To respond to some of the comments from the previous version, I am fine with the list_head being a pointer considering there can only be one list_head in this struct definition.

    struct kunit_try_catch try_catch;
    /* param_value is the current parameter value for a test case. */
    const void *param_value;

@@ -314,7 +325,7 @@ const char *kunit_filter_glob(void); char *kunit_filter(void); char *kunit_filter_action(void);

-void kunit_init_test(struct kunit *test, const char *name, char *log); +void kunit_init_test(struct kunit *test, const char *name, struct list_head *log);

int kunit_run_tests(struct kunit_suite *suite);

@@ -472,7 +483,7 @@ static inline void *kunit_kcalloc(struct kunit *test, size_t n, size_t size, gfp

void kunit_cleanup(struct kunit *test);

-void __printf(2, 3) kunit_log_append(char *log, const char *fmt, ...); +void __printf(2, 3) kunit_log_append(struct list_head *log, const char *fmt, ...);

/**

• kunit_mark_skipped() - Marks @test_or_suite as skipped

diff --git a/lib/kunit/debugfs.c b/lib/kunit/debugfs.c index 22c5c496a68f..a26b6d31bd2f 100644 --- a/lib/kunit/debugfs.c +++ b/lib/kunit/debugfs.c @@ -5,6 +5,7 @@ */

#include <linux/debugfs.h> +#include <linux/list.h> #include <linux/module.h>

#include <kunit/test.h> @@ -37,14 +38,15 @@ void kunit_debugfs_init(void) debugfs_rootdir = debugfs_create_dir(KUNIT_DEBUGFS_ROOT, NULL); }

-static void debugfs_print_result(struct seq_file *seq,

•                            struct kunit_suite *suite,
  

•                            struct kunit_case *test_case)
  

+static void debugfs_print_log(struct seq_file *seq, const struct list_head *log) {

•   if (!test_case || !test_case->log)
  

•   struct kunit_log_frag *frag;
  

•   if (!log)
            return;
  
  

•   seq_printf(seq, "%s", test_case->log);
  

•   list_for_each_entry(frag, log, list)
  

•           seq_puts(seq, frag->buf);
  

}

/* @@ -69,10 +71,9 @@ static int debugfs_print_results(struct seq_file *seq, void *v) seq_printf(seq, KUNIT_SUBTEST_INDENT "1..%zd\n", kunit_suite_num_test_cases(suite));

    kunit_suite_for_each_test_case(suite, test_case)

•           debugfs_print_result(seq, suite, test_case);
  

•           debugfs_print_log(seq, test_case->log);
  
  

•   if (suite->log)
  

•           seq_printf(seq, "%s", suite->log);
  

•   debugfs_print_log(seq, suite->log);
  
    seq_printf(seq, "%s %d %s\n",
               kunit_status_to_ok_not_ok(success), 1, suite->name);
  

@@ -100,14 +101,53 @@ static const struct file_operations debugfs_results_fops = { .release = debugfs_release, };

+static struct list_head *kunit_debugfs_alloc_log(void) +{

•   struct list_head *log;
  

•   struct kunit_log_frag *frag;
  

•   log = kzalloc(sizeof(*log), GFP_KERNEL);
  

•   if (!log)
  

•           return NULL;
  

•   INIT_LIST_HEAD(log);
  

•   frag = kmalloc(sizeof(*frag), GFP_KERNEL);
  

•   if (!frag) {
  

•           kfree(log);
  

•           return NULL;
  

•   }
  

•   kunit_init_log_frag(frag);
  

•   list_add_tail(&frag->list, log);
  

•   return log;
  

+}

+static void kunit_debugfs_free_log(struct list_head *log) +{

•   struct kunit_log_frag *frag, *n;
  

•   if (!log)
  

•           return;
  

•   list_for_each_entry_safe(frag, n, log, list) {
  

•           list_del(&frag->list);
  

•           kfree(frag);
  

•   }
  

•   kfree(log);
  

+}

void kunit_debugfs_create_suite(struct kunit_suite *suite) { struct kunit_case *test_case;

    /* Allocate logs before creating debugfs representation. */

•   suite->log = kzalloc(KUNIT_LOG_SIZE, GFP_KERNEL);
  

•   suite->log = kunit_debugfs_alloc_log();
  

•   kunit_suite_for_each_test_case(suite, test_case)
  

•           test_case->log = kzalloc(KUNIT_LOG_SIZE, GFP_KERNEL);
  

•           test_case->log = kunit_debugfs_alloc_log();
  
    suite->debugfs = debugfs_create_dir(suite->name, debugfs_rootdir);
  
  

@@ -121,7 +161,8 @@ void kunit_debugfs_destroy_suite(struct kunit_suite *suite) struct kunit_case *test_case;

    debugfs_remove_recursive(suite->debugfs);

•   kfree(suite->log);
  

•   kunit_debugfs_free_log(suite->log);
  

•   kunit_suite_for_each_test_case(suite, test_case)
  

•           kfree(test_case->log);
  

•           kunit_debugfs_free_log(test_case->log);
  

} diff --git a/lib/kunit/kunit-test.c b/lib/kunit/kunit-test.c index 83d8e90ca7a2..a199f83bac67 100644 --- a/lib/kunit/kunit-test.c +++ b/lib/kunit/kunit-test.c @@ -530,12 +530,37 @@ 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) +{

•   struct kunit_log_frag *frag;
  

•   size_t len = 0;
  

•   char *p;
  

I wonder if we could change the name of p to be a bit more descriptive. Maybe concat_log?

•   list_for_each_entry(frag, log, list)
  

•           len += strlen(frag->buf);
  

•   len++; /* for terminating '\0' */
  

•   p = kunit_kzalloc(test, len, GFP_KERNEL);
  

•   list_for_each_entry(frag, log, list)
  

•           strlcat(p, frag->buf, len);
  

•   return p;
  

+}

static void kunit_log_test(struct kunit *test) { struct kunit_suite suite;

•   struct kunit_log_frag *frag;
  
  

•   suite.log = kunit_kzalloc(test, KUNIT_LOG_SIZE, GFP_KERNEL);
  

•   suite.log = kunit_kzalloc(test, sizeof(*suite.log), GFP_KERNEL);
    KUNIT_ASSERT_NOT_ERR_OR_NULL(test, suite.log);
  

•   INIT_LIST_HEAD(suite.log);
  

This section of the test is pretty dense. I would love to see at least one comment in this section. Maybe it could be here and say something like: "/* Allocate, initialize, and then add the first fragment of 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);
  
    kunit_log(KERN_INFO, test, "put this in log.");
    kunit_log(KERN_INFO, test, "this too.");
  

@@ -543,14 +568,17 @@ static void kunit_log_test(struct kunit *test) kunit_log(KERN_INFO, &suite, "along with this.");

#ifdef CONFIG_KUNIT_DEBUGFS

•   frag = list_first_entry(test->log, struct kunit_log_frag, list);
    KUNIT_EXPECT_NOT_ERR_OR_NULL(test,
  

•                                strstr(test->log, "put this in log."));
  

•                                strstr(frag->buf, "put this in log."));
    KUNIT_EXPECT_NOT_ERR_OR_NULL(test,
  

•                                strstr(test->log, "this too."));
  

•                                strstr(frag->buf, "this too."));
  

•   frag = list_first_entry(suite.log, struct kunit_log_frag, list);
    KUNIT_EXPECT_NOT_ERR_OR_NULL(test,
  

•                                strstr(suite.log, "add to suite log."));
  

•                                strstr(frag->buf, "add to suite log."));
    KUNIT_EXPECT_NOT_ERR_OR_NULL(test,
  

•                                strstr(suite.log, "along with this."));
  

•                                strstr(frag->buf, "along with this."));
  

#else KUNIT_EXPECT_NULL(test, test->log);

This test passes when CONFIG_KUNIT_DEBUGFS=n while most of the other tests are skipped. Should this test be skipped instead?

I'm assuming since the assert/expect statements at the beginning are run even if CONFIG_KUNIT_DEBUGFS=n, this test should not be skipped but I just wanted to check.

#endif @@ -558,11 +586,15 @@ static void kunit_log_test(struct kunit *test)

static void kunit_log_newline_test(struct kunit *test) {

•   struct kunit_log_frag *frag;
  

•   kunit_info(test, "Add newline\n");
    if (test->log) {
  

This is a small nit but I would prefer that the if statements to decide whether CONFIG_KUNIT_DEBUGFS is enabled were uniform. So I would prefer that we choose between if (test->log) and #ifdef CONFIG_KUNIT_DEBUGFS. I think we originally chose to use if (test->log) here to avoid the compile-time #ifdef.

•           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"));
  

•           frag = list_first_entry(test->log, struct kunit_log_frag, list);
  

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

•                   "Missing log line, full log:\n%s",
  

•                   get_concatenated_log(test, test->log));
  

•           KUNIT_EXPECT_NULL(test, strstr(frag->buf, "Add newline\n\n"));
    } else {
            kunit_skip(test, "only useful when debugfs is enabled");
    }
  

diff --git a/lib/kunit/test.c b/lib/kunit/test.c index 49698a168437..dfe51bc2b387 100644 --- a/lib/kunit/test.c +++ b/lib/kunit/test.c @@ -11,6 +11,7 @@ #include <kunit/test-bug.h> #include <kunit/attributes.h> #include <linux/kernel.h> +#include <linux/list.h> #include <linux/module.h> #include <linux/moduleparam.h> #include <linux/panic.h> @@ -114,46 +115,66 @@ static void kunit_print_test_stats(struct kunit *test,

• already present.
• @log: The log to add the newline to.

*/ -static void kunit_log_newline(char *log) +static void kunit_log_newline(struct kunit_log_frag *frag) { int log_len, len_left;

•   log_len = strlen(log);
  

•   len_left = KUNIT_LOG_SIZE - log_len - 1;
  

•   log_len = strlen(frag->buf);
  

•   len_left = sizeof(frag->buf) - log_len - 1;
  
  

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

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

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

•           strncat(frag->buf, "\n", len_left);
  

}

-/*

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

-void kunit_log_append(char *log, const char *fmt, ...) +static struct kunit_log_frag *kunit_log_extend(struct list_head *log)

I would love to see just a short comment describing kunit_log_extend to prevent confusion with kunit_log_append.

+{

•   struct kunit_log_frag *frag;
  

•   frag = kmalloc(sizeof(*frag), GFP_KERNEL);
  

•   if (!frag)
  

•           return NULL;
  

•   kunit_init_log_frag(frag);
  

•   list_add_tail(&frag->list, log);
  

•   return frag;
  

+}

+/* Append formatted message to log, extending the log buffer if necessary. */ +void kunit_log_append(struct list_head *log, const char *fmt, ...) { va_list args;

•   struct kunit_log_frag *frag;
    int len, log_len, len_left;
  
    if (!log)
            return;
  
  

•   log_len = strlen(log);
  

•   len_left = KUNIT_LOG_SIZE - log_len - 1;
  

•   if (len_left <= 0)
  

•           return;
  

•   frag = list_last_entry(log, struct kunit_log_frag, list);
  

•   log_len = strlen(frag->buf);
  

•   len_left = sizeof(frag->buf) - log_len - 1;
  
    /* Evaluate length of line to add to log */
    va_start(args, fmt);
    len = vsnprintf(NULL, 0, fmt, args) + 1;
    va_end(args);
  
  

•   if (len > len_left) {
  

•           frag = kunit_log_extend(log);
  

•           if (!frag)
  

•                   return;
  

•           len_left = sizeof(frag->buf) - 1;
  

•           log_len = 0;
  

•   }
  

•   /* Print formatted line to the log */
    va_start(args, fmt);
  

•   vsnprintf(log + log_len, min(len, len_left), fmt, args);
  

•   vsnprintf(frag->buf + 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);
  

•   kunit_log_newline(frag);
  

} EXPORT_SYMBOL_GPL(kunit_log_append);

@@ -359,14 +380,18 @@ void __kunit_do_failed_assertion(struct kunit *test, } EXPORT_SYMBOL_GPL(__kunit_do_failed_assertion);

-void kunit_init_test(struct kunit *test, const char *name, char *log) +void kunit_init_test(struct kunit *test, const char *name, struct list_head *log) { spin_lock_init(&test->lock); INIT_LIST_HEAD(&test->resources); test->name = name; test->log = log;

•   if (test->log)
  

•           test->log[0] = '\0';
  

•   if (test->log) {
  

•           struct kunit_log_frag *frag = list_first_entry(test->log,
  

•                                                          struct kunit_log_frag,
  

•                                                          list);
  

•           frag->buf[0] = '\0';
  

•   }
    test->status = KUNIT_SUCCESS;
    test->status_comment[0] = '\0';
  

}

2.30.2

On Wed, 9 Aug 2023 at 23:54, Richard Fitzgerald rf@opensource.cirrus.com wrote:

Add handling to kunit_log_append() for log messages that are longer than a single buffer fragment.

The initial implementation of fragmented buffers did not change the logic of the original kunit_log_append(). A consequence was that it still had the original assumption that a log line will fit into one buffer.

This patch checks for log messages that are larger than one fragment buffer. In that case, kvasprintf() is used to format it into a temporary buffer and that content is then split across as many fragments as necessary.

Signed-off-by: Richard Fitzgerald rf@opensource.cirrus.com

I think this looks good (and is a long-overdue addition to the logging functionality).

One thought I have (and I'm kicking myself for not thinking of it earlier) is that this is starting to get very similar to the "string stream" functionality in lib/kunit/string-stream.{h,c}. Now, I actually think this implementation is much more efficient (using larger fragments, whereas the string stream uses variable-sized ones). Particularly since there are a lot of cases where string streams are created, converted to a string, and then logged, there's almost certainly a bunch of redundant work being done here.

My gut feeling is that we should stick with this as-is, and maybe try to either work out some better integration between string streams and logging (to avoid that extra string allocation) or find some way of combining them.

Regardless, this seems good as-is to me. There are some minor comments below, but nothing disastrous. I'll let Rae have a look over the various strscpy and strlcat calls, though, as while I did check them carefully (and KASAN hasn't complained), it's always best to have as many eyes on C string code as possible. :-)

But in my eyes, this is Reviewed-by: David Gow davidgow@google.com

Cheers, -- David

lib/kunit/test.c | 65 +++++++++++++++++++++++++++++++++++++++++++++--- 1 file changed, 61 insertions(+), 4 deletions(-)

diff --git a/lib/kunit/test.c b/lib/kunit/test.c index dfe51bc2b387..28d0048d6171 100644 --- a/lib/kunit/test.c +++ b/lib/kunit/test.c @@ -140,25 +140,82 @@ static struct kunit_log_frag *kunit_log_extend(struct list_head *log) return frag; }

+static void kunit_log_append_string(struct list_head *log, const char *src) +{

•   struct kunit_log_frag *frag, *new_frag;
  

•   int log_len, bytes_left;
  

•   ssize_t written;
  

•   char *p;
  

•   frag = list_last_entry(log, struct kunit_log_frag, list);
  

•   log_len = strlen(frag->buf);
  

•   bytes_left = sizeof(frag->buf) - log_len;
  

•   written = strscpy(frag->buf + log_len, src, bytes_left);
  

•   if (written != -E2BIG)
  

•           goto newline;
  

•   src += bytes_left - 1;
  

•   do {
  

•           new_frag = kunit_log_extend(log);
  

•           if (!new_frag)
  

•                   goto newline;
  

•           frag = new_frag;
  

•           written = strscpy(frag->buf, src, sizeof(frag->buf));
  

•           src += sizeof(frag->buf) - 1;
  

•   } while (written == -E2BIG);
  

+newline:

•   if (written == -E2BIG)
  

I think that this can only be true if kunit_log_extend() fails. If the do/while loop ends naturally, then written != -E2BIG, as is the case with the strscpy goto above.

Do you think it's cleaner to move the 'written = strlen(frag->buf) into the if (!new_frag) statement within the loop?

•           written = strlen(frag->buf);
  

•   p = &frag->buf[written - 1];
  

•   if (*p != '\n') {
  

•           if (strlcat(frag->buf, "\n", sizeof(frag->buf)) >= sizeof(frag->buf)) {
  

•                   frag = kunit_log_extend(log);
  

•                   if (!frag) {
  

A comment here could be useful. Something like "If we can't extend the log to add a newline, truncate the last message".

•                           *p = '\n';
  

•                           return;
  

•                   }
  

•                   frag->buf[0] = '\n';
  

•                   frag->buf[1] = '\0';
  

•           }
  

•   }
  

+}

/* Append formatted message to log, extending the log buffer if necessary. */ void kunit_log_append(struct list_head *log, const char *fmt, ...) { va_list args; struct kunit_log_frag *frag; int len, log_len, len_left;

•   char *tmp = NULL;
  
    if (!log)
            return;
  
  

•   frag = list_last_entry(log, struct kunit_log_frag, list);
  

•   log_len = strlen(frag->buf);
  

•   len_left = sizeof(frag->buf) - log_len - 1;
  

•   /* Evaluate length of line to add to log */
    va_start(args, fmt);
    len = vsnprintf(NULL, 0, fmt, args) + 1;
    va_end(args);
  
  

•   if (len > sizeof(frag->buf) - 1) {
  

•           va_start(args, fmt);
  

•           tmp = kvasprintf(GFP_KERNEL, fmt, args);
  

•           va_end(args);
  

Should we handle the case where kvasprintf() fails here and drop the log message?

•           kunit_log_append_string(log, tmp);
  

•           kfree(tmp);
  

•           return;
  

•   }
  

•   frag = list_last_entry(log, struct kunit_log_frag, list);
  

•   log_len = strlen(frag->buf);
  

•   len_left = sizeof(frag->buf) - log_len - 1;
  

•   if (len > len_left) {
            frag = kunit_log_extend(log);
            if (!frag)
  

-- 2.30.2

On 9/8/23 22:22, Rae Moar wrote:

On Wed, Aug 9, 2023 at 11:54 AM Richard Fitzgerald rf@opensource.cirrus.com wrote:

...

If a log string is the exact length of a log fragment buffer kunit_log_append() should now exactly fill that fragment without extending the log.

Signed-off-by: Richard Fitzgerald rf@opensource.cirrus.com

Hello!

This test looks good to me. I have tested it and it seems to be working well.

I appreciate all of the assert and expect statements. I do have one comment below.

Although, I would be happy to set this as reviewed by me after that comment is responded to.

Thanks! -Rae

...

---

lib/kunit/kunit-test.c | 37 +++++++++++++++++++++++++++++++++++++ 1 file changed, 37 insertions(+)

diff --git a/lib/kunit/kunit-test.c b/lib/kunit/kunit-test.c index c0ee33a8031e..9ac81828d018 100644 --- a/lib/kunit/kunit-test.c +++ b/lib/kunit/kunit-test.c @@ -763,12 +763,49 @@ static void kunit_log_extend_test_2(struct kunit *test) #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_kzalloc(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);
  

•   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);
  

Should this be an EXPECT instead? It doesn't seem like the test needs to fail immediately if this fails. Let me know what you think.

I think ASSERT is appropriate here. This isn't testing anything (unless you don't trust memset). It's ensuring that the test data I generate is what I expect otherwise the following testing is invalid.

This is redundant because the first 3 lines must produce the expected string, but I put it in to prove to myself that I can do math and decided to leave it in.

On Wed, Aug 9, 2023 at 10:54 AM Richard Fitzgerald rf@opensource.cirrus.com wrote:

Add kunit_log_long_line_test() to test that logging a line longer than the buffer fragment size doesn't truncate the line.

Add extra tests to kunit_log_newline_test() for lines longer than the buffer fragment size.

Signed-off-by: Richard Fitzgerald rf@opensource.cirrus.com

Hello!

This test looks good to me. I have included just a few comments below.

Reviewed-by: Rae Moar rmoar@google.com

Thanks! -Rae

---

lib/kunit/kunit-test.c | 84 +++++++++++++++++++++++++++++++++++++++++- 1 file changed, 83 insertions(+), 1 deletion(-)

diff --git a/lib/kunit/kunit-test.c b/lib/kunit/kunit-test.c index 9ac81828d018..c079550c3afd 100644 --- a/lib/kunit/kunit-test.c +++ b/lib/kunit/kunit-test.c @@ -609,7 +609,7 @@ static void kunit_log_newline_test(struct kunit *test) { struct kunit_suite suite; struct kunit_log_frag *frag;

•   char *p;
  

•   char *p, *line;
  
    kunit_info(test, "Add newline\n");
    if (test->log) {
  

@@ -635,6 +635,33 @@ static void kunit_log_newline_test(struct kunit *test) 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);

•           kunit_kfree(test, p);
  

I really like the thoroughness of this test. However, I do wonder if this newline test could be broken into at least 2 parts as the test is quite long with all these additions. I spoke on this in a previous patch and just wanted to touch on it here as well.

•           /* String that is much longer than a fragment */
  

•           line = kunit_kzalloc(test, sizeof(frag->buf) * 6, GFP_KERNEL);
  

•           KUNIT_ASSERT_NOT_ERR_OR_NULL(test, line);
  

•           memset(line, 'x', (sizeof(frag->buf) * 6) - 1);
  

•           kunit_log_append(suite.log, "%s", line);
  

•           p = get_concatenated_log(test, suite.log, NULL);
  

•           KUNIT_ASSERT_NOT_ERR_OR_NULL(test, p);
  

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

•           KUNIT_EXPECT_NULL(test, strstr(p, "\n\n"));
  

•           kunit_kfree(test, p);
  

I would also consider adding comments between these three cases to describe their differences and maybe what the desired behavior would be.

•           kunit_log_append(suite.log, "%s\n", line);
  

•           p = get_concatenated_log(test, suite.log, NULL);
  

•           KUNIT_ASSERT_NOT_ERR_OR_NULL(test, p);
  

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

•           KUNIT_EXPECT_NULL(test, strstr(p, "\n\n"));
  

•           kunit_kfree(test, p);
  

•           line[strlen(line) - 1] = '\n';
  

•           kunit_log_append(suite.log, "%s", line);
  

•           p = get_concatenated_log(test, suite.log, NULL);
  

•           KUNIT_ASSERT_NOT_ERR_OR_NULL(test, p);
  

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

•           KUNIT_EXPECT_NULL(test, strstr(p, "\n\n"));
  

•           kunit_kfree(test, p);
    } else {
            kunit_skip(test, "only useful when debugfs is enabled");
    }
  

@@ -799,6 +826,60 @@ static void kunit_log_frag_sized_line_test(struct kunit *test) #endif }

+static void kunit_log_long_line_test(struct kunit *test) +{ +#ifdef CONFIG_KUNIT_DEBUGFS

•   struct kunit_suite suite;
  

•   struct kunit_log_frag *frag;
  

•   struct rnd_state rnd;
  

•   char *line, *p, *pn;
  

•   size_t line_buf_size, len;
  

•   int 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);
  

•   /* Create a very long string to be logged */
  

•   line_buf_size = sizeof(frag->buf) * 6;
  

•   line = kunit_kmalloc(test, line_buf_size, GFP_KERNEL);
  

•   KUNIT_ASSERT_NOT_ERR_OR_NULL(test, line);
  

•   line[0] = '\0';
  

•   prandom_seed_state(&rnd, 3141592653589793238ULL);
  

I was a little worried about including a randomized string but since it does not need to be reproduced here it should be fine. I also haven't seen any issues with the tests with the randomized strings being nondeterministic.

•   len = 0;
  

•   do {
  

•           static const char fill[] =
  

•                   "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
  

•           i = prandom_u32_state(&rnd) % (sizeof(fill) - 1);
  

•           len = strlcat(line, &fill[i], line_buf_size);
  

•   } while (len < line_buf_size);
  

•   kunit_log_append(suite.log, "%s\n", line);
  

•   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_frags:%d total len:%zu\n", num_frags, strlen(p));
  

•   /* Don't compare the trailing '\n' */
  

•   pn = strrchr(p, '\n');
  

•   KUNIT_EXPECT_NOT_ERR_OR_NULL(test, pn);
  

•   *pn = '\0';
  

•   KUNIT_EXPECT_EQ(test, strlen(p), strlen(line));
  

•   KUNIT_EXPECT_STREQ(test, p, line);
  

+#else

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

+#endif +}

static struct kunit_case kunit_log_test_cases[] = { KUNIT_CASE(kunit_log_init_frag_test), KUNIT_CASE(kunit_log_test), @@ -806,6 +887,7 @@ static struct kunit_case kunit_log_test_cases[] = { KUNIT_CASE(kunit_log_extend_test_1), KUNIT_CASE(kunit_log_extend_test_2), KUNIT_CASE(kunit_log_frag_sized_line_test),

•   KUNIT_CASE(kunit_log_long_line_test),
    {}
  

};

-- 2.30.2

On Wed, Aug 9, 2023 at 10:54 AM Richard Fitzgerald rf@opensource.cirrus.com wrote:

Add a test that logging a string containing only a newline appends one newline to the log.

Signed-off-by: Richard Fitzgerald rf@opensource.cirrus.com

This is a really great idea to include a test for the simple addition of only a newline character.

This patch looks good to me. The only comment is that the newline test is quite large and could be broken up as I said on the previous patch.

Reviewed-by: Rae Moar rmoar@google.com

Thanks! -Rae

---

lib/kunit/kunit-test.c | 6 ++++++ 1 file changed, 6 insertions(+)

diff --git a/lib/kunit/kunit-test.c b/lib/kunit/kunit-test.c index c079550c3afd..7e710c73c7e5 100644 --- a/lib/kunit/kunit-test.c +++ b/lib/kunit/kunit-test.c @@ -627,6 +627,12 @@ static void kunit_log_newline_test(struct kunit *test) kunit_init_log_frag(frag); list_add_tail(&frag->list, suite.log);

•           /* Log only a newline */
  

•           kunit_log_append(suite.log, "\n");
  

•           KUNIT_EXPECT_TRUE(test, list_is_singular(suite.log));
  

•           KUNIT_EXPECT_STREQ(test, frag->buf, "\n");
  

•           frag->buf[0] = '\0';
  

•           /* 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);
  

-- 2.30.2

On Wed, Aug 9, 2023 at 10:54 AM Richard Fitzgerald rf@opensource.cirrus.com wrote:

It's wasteful to call vsnprintf() only to figure out the length of the string. The string might fit in the available buffer space but we have to vsnprintf() again to do that.

Instead, attempt to format the string to the available buffer at the same time as finding the string length. Only if the string didn't fit the available space is it necessary to extend the log and format the string again to a new fragment buffer.

Signed-off-by: Richard Fitzgerald rf@opensource.cirrus.com

Hello!

I find this version slightly more confusing but I realize that the extra vsnprintf() call is unnecessary. So I am ok with this version except for one question below.

I am curious what David Gow thinks and it would also be good to have another set of eyes here.

My testing of this showed no problems.

Thanks! -Rae

---

lib/kunit/test.c | 33 +++++++++++++++++---------------- 1 file changed, 17 insertions(+), 16 deletions(-)

diff --git a/lib/kunit/test.c b/lib/kunit/test.c index 28d0048d6171..230ec5e9824f 100644 --- a/lib/kunit/test.c +++ b/lib/kunit/test.c @@ -196,11 +196,21 @@ void kunit_log_append(struct list_head *log, const char *fmt, ...) if (!log) return;

•   /* Evaluate length of line to add to log */
  

•   frag = list_last_entry(log, struct kunit_log_frag, list);
  

•   log_len = strlen(frag->buf);
  

•   len_left = sizeof(frag->buf) - log_len - 1;
  

•   /* Attempt to print formatted line to current fragment */
    va_start(args, fmt);
  

•   len = vsnprintf(NULL, 0, fmt, args) + 1;
  

•   len = vsnprintf(frag->buf + log_len, len_left, fmt, args) + 1;
    va_end(args);
  
  

•   if (len <= len_left)
  

•           goto out_newline;
  

•   /* Abandon the truncated result of vsnprintf */
  

•   frag->buf[log_len] = '\0';
  

•   if (len > sizeof(frag->buf) - 1) {
            va_start(args, fmt);
            tmp = kvasprintf(GFP_KERNEL, fmt, args);
  

@@ -212,24 +222,15 @@ void kunit_log_append(struct list_head *log, const char *fmt, ...) return; }

•   frag = list_last_entry(log, struct kunit_log_frag, list);
  

•   log_len = strlen(frag->buf);
  

•   len_left = sizeof(frag->buf) - log_len - 1;
  

•   if (len > len_left) {
  

•           frag = kunit_log_extend(log);
  

•           if (!frag)
  

•                   return;
  

•           len_left = sizeof(frag->buf) - 1;
  

•           log_len = 0;
  

•   }
  

•   frag = kunit_log_extend(log);
  

Are we meant to be using the remainder of the last fragment to its capacity or just start again with a new fragment and leave some of the last fragment empty? I worry we abandoned using the last fragment or is that the intention? Let me know if I understand this correctly.

•   if (!frag)
  

•           return;
  
    /* Print formatted line to the log */
    va_start(args, fmt);
  

•   vsnprintf(frag->buf + log_len, min(len, len_left), fmt, args);
  

•   vsnprintf(frag->buf, sizeof(frag->buf) - 1, fmt, args);
    va_end(args);
  

+out_newline: /* Add newline to end of log if not already present. */ kunit_log_newline(frag); } -- 2.30.2