Re: [PATCH v5 2/3] printf: break kunit into test cases

On Fri 2025-02-21 15:34:31, Tamir Duberstein wrote:

Move all tests into `printf_test_cases`. This gives us nicer output in the event of a failure.

Combine `plain_format` and `plain_hash` into `hash_pointer` since they're testing the same scenario.

Signed-off-by: Tamir Duberstein tamird@gmail.com

lib/tests/printf_kunit.c | 331 +++++++++++++++++------------------------------ 1 file changed, 121 insertions(+), 210 deletions(-)

diff --git a/lib/tests/printf_kunit.c b/lib/tests/printf_kunit.c index 287bbfb61148..013df6f6dd49 100644 --- a/lib/tests/printf_kunit.c +++ b/lib/tests/printf_kunit.c @@ -38,13 +38,8 @@ static unsigned int total_tests; static char *test_buffer; static char *alloced_buffer; -static struct kunit *kunittest;

-#define tc_fail(fmt, ...) \

• KUNIT_FAIL(kunittest, fmt, ##__VA_ARGS__)

-static void __printf(4, 0) -do_test(int bufsize, const char *expect, int elen, +static void __printf(5, 0) +do_test(struct kunit *kunittest, int bufsize, const char *expect, int elen, const char *fmt, va_list ap) { va_list aq; @@ -58,59 +53,64 @@ do_test(int bufsize, const char *expect, int elen,

[...]

if (memcmp(test_buffer, expect, written)) {

• tc_fail("vsnprintf(buf, %d, \"%s\", ...) wrote '%s', expected '%.*s'",
  

• 	bufsize, fmt, test_buffer, written, expect);
  

• KUNIT_FAIL(kunittest, "vsnprintf(buf, %d, \"%s\", ...) wrote '%s', expected '%.*s'",
  

• 	   bufsize, fmt, test_buffer, written, expect);
  

  return; }

} -static void __printf(3, 4) -__test(const char *expect, int elen, const char *fmt, ...) +static void __printf(4, 0)

This should be:

static void __printf(4, 5)

The 2nd parameter is zero when the variable list of parameters is passed using va_list.

+__test(struct kunit *kunittest, const char *expect, int elen, const char *fmt, ...) { va_list ap; int rand; char *p;

@@ -247,89 +225,44 @@ plain_format(void) #define ZEROS "" #define ONES "" -static int -plain_format(void) -{

• /* Format is implicitly tested for 32 bit machines by plain_hash() */
• return 0;

-}

#endif /* BITS_PER_LONG == 64 */ -static int -plain_hash_to_buffer(const void *p, char *buf, size_t len) +static void +plain_hash_to_buffer(struct kunit *kunittest, const void *p, char *buf, size_t len) {

• int nchars;
• nchars = snprintf(buf, len, "%p", p);
• if (nchars != PTR_WIDTH)

• return -1;
  

• KUNIT_ASSERT_EQ(kunittest, snprintf(buf, len, "%p", p), PTR_WIDTH);

if (strncmp(buf, PTR_VAL_NO_CRNG, PTR_WIDTH) == 0) { kunit_warn(kunittest, "crng possibly not yet initialized. plain 'p' buffer contains "%s"", PTR_VAL_NO_CRNG);

• return 0;
  

  }
• return 0;

} -static int -plain_hash(void) -{

• char buf[PLAIN_BUF_SIZE];
• int ret;
• ret = plain_hash_to_buffer(PTR, buf, PLAIN_BUF_SIZE);
• if (ret)

• return ret;
  

• if (strncmp(buf, PTR_STR, PTR_WIDTH) == 0)

• return -1;
  

• return 0;

-}

-/*

• • We can't use test() to test %p because we don't know what output to expect
• • after an address is hashed.
• */

static void -plain(void) +hash_pointer(struct kunit *kunittest) {

• int err;

• if (no_hash_pointers)

• kunit_skip(kunittest, "hash pointers disabled");
  

• if (no_hash_pointers) {

• kunit_warn(kunittest, "skipping plain 'p' tests");
  

• return;
  

• }

• char buf[PLAIN_BUF_SIZE];

• err = plain_hash();
• if (err) {

• tc_fail("plain 'p' does not appear to be hashed");
  

• return;
  

• }

• plain_hash_to_buffer(kunittest, PTR, buf, PLAIN_BUF_SIZE);

• err = plain_format();
• if (err) {

• tc_fail("hashing plain 'p' has unexpected format");
  

• }

• /*

• * We can't use test() to test %p because we don't know what output to expect
  

• * after an address is hashed.
  

• */
  

The code does not longer print a reasonable error message on failure. I would extend the comment to make it easier to understand the meaning. Also I would use the imperative style. Something like:

/* * The hash of %p is unpredictable, therefore test() cannot be used. * Instead, verify that the first 32 bits are zeros on a 64-bit system, * and confirm the non-hashed value is not printed. */

• KUNIT_EXPECT_MEMEQ(kunittest, buf, ZEROS, strlen(ZEROS));
• KUNIT_EXPECT_MEMNEQ(kunittest, buf+strlen(ZEROS), PTR_STR, PTR_WIDTH);

This looks wrong. It should be either:

KUNIT_EXPECT_MEMNEQ(kunittest, buf, PTR_STR, PTR_WIDTH);

or

KUNIT_EXPECT_MEMNEQ(kunittest, buf + strlen(ZEROS), PTR_STR + strlen(ZEROS), PTR_WIDTH - strlen(ZEROS));

I would use the 1st variant. It is easier and it works the same way as the original check.

Anyway, it is a great clean up of the pointer tests. I have wanted to do it since a long time but I never found time.

} static void -test_hashed(const char *fmt, const void *p) +test_hashed(struct kunit *kunittest, const char *fmt, const void *p) { char buf[PLAIN_BUF_SIZE];

• int ret;

• /*

• * No need to increase failed test counter since this is assumed
  

• * to be called after plain().
  

• */
  

• ret = plain_hash_to_buffer(p, buf, PLAIN_BUF_SIZE);
• if (ret)

• return;
  

• plain_hash_to_buffer(kunittest, p, buf, PLAIN_BUF_SIZE);

test(buf, fmt, p); } @@ -739,11 +664,9 @@ flags(void) (unsigned long) gfp); gfp |= __GFP_HIGH; test(cmp_buffer, "%pGg", &gfp);

• kfree(cmp_buffer);

I belive that the kfree() should stay. Otherwise, the test leaks memory in every run.

} -static void fwnode_pointer(void) +static void fwnode_pointer(struct kunit *kunittest) { const struct software_node first = { .name = "first" }; const struct software_node second = { .name = "second", .parent = &first };

Otherwise, it looks good to me.

Best Regards, Petr