[PATCH v5 1/3] printf: convert self-test to KUnit

Tamir Duberstein
2025-02-21T20:34:39Z

Convert the printf() self-test to a KUnit test.

In the interest of keeping the patch reasonably-sized this doesn't
refactor the tests into proper parameterized tests - it's all one big
test case.

Signed-off-by: Tamir Duberstein <tamird@gmail.com>
---
Documentation/core-api/printk-formats.rst | 4 +-
MAINTAINERS | 2 +-
lib/Kconfig.debug | 12 +-
lib/Makefile | 1 -
lib/tests/Makefile | 1 +
lib/{test_printf.c => tests/printf_kunit.c} | 188 +++++++++++++++-------------
tools/testing/selftests/lib/config | 1 -
tools/testing/selftests/lib/printf.sh | 4 -
8 files changed, 117 insertions(+), 96 deletions(-)

diff --git a/Documentation/core-api/printk-formats.rst b/Documentation/core-api/printk-formats.rst
index ecccc0473da9..4bdc394e86af 100644
--- a/Documentation/core-api/printk-formats.rst
+++ b/Documentation/core-api/printk-formats.rst
@@ -661,7 +661,7 @@ Do *not* use it from C.
Thanks
======

-If you add other %p extensions, please extend <lib/test_printf.c> with
-one or more test cases, if at all feasible.
+If you add other %p extensions, please extend <lib/tests/printf_kunit.c>
+with one or more test cases, if at all feasible.

Thank you for your cooperation and attention.
diff --git a/MAINTAINERS b/MAINTAINERS
index f076360ce3c6..b051ccf6b276 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -25510,8 +25510,8 @@ R: Sergey Senozhatsky <senozhatsky@chromium.org>
S: Maintained
T: git git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux.git
F: Documentation/core-api/printk-formats.rst
-F: lib/test_printf.c
F: lib/test_scanf.c
+F: lib/tests/printf_kunit.c
F: lib/vsprintf.c

VT1211 HARDWARE MONITOR DRIVER
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 7ddbfdacf895..d2b15f633227 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -2436,6 +2436,15 @@ config ASYNC_RAID6_TEST
config TEST_HEXDUMP
tristate "Test functions located in the hexdump module at runtime"

+config PRINTF_KUNIT_TEST
+ tristate "KUnit test printf() family of functions at runtime" if !KUNIT_ALL_TESTS
+ depends on KUNIT
+ default KUNIT_ALL_TESTS
+ help
+ Enable this option to test the printf functions at runtime.
+
+ If unsure, say N.
+
config STRING_KUNIT_TEST
tristate "KUnit test string functions at runtime" if !KUNIT_ALL_TESTS
depends on KUNIT
@@ -2449,9 +2458,6 @@ config STRING_HELPERS_KUNIT_TEST
config TEST_KSTRTOX
tristate "Test kstrto*() family of functions at runtime"

-config TEST_PRINTF
- tristate "Test printf() family of functions at runtime"
-
config TEST_SCANF
tristate "Test scanf() family of functions at runtime"

diff --git a/lib/Makefile b/lib/Makefile
index 961aef91d493..f31e6a3100ba 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -77,7 +77,6 @@ obj-$(CONFIG_TEST_RHASHTABLE) += test_rhashtable.o
obj-$(CONFIG_TEST_STATIC_KEYS) += test_static_keys.o
obj-$(CONFIG_TEST_STATIC_KEYS) += test_static_key_base.o
obj-$(CONFIG_TEST_DYNAMIC_DEBUG) += test_dynamic_debug.o
-obj-$(CONFIG_TEST_PRINTF) += test_printf.o
obj-$(CONFIG_TEST_SCANF) += test_scanf.o

obj-$(CONFIG_TEST_BITMAP) += test_bitmap.o
diff --git a/lib/tests/Makefile b/lib/tests/Makefile
index 8961fbcff7a4..183c6a838a5d 100644
--- a/lib/tests/Makefile
+++ b/lib/tests/Makefile
@@ -30,6 +30,7 @@ obj-$(CONFIG_LINEAR_RANGES_TEST) += test_linear_ranges.o
obj-$(CONFIG_MEMCPY_KUNIT_TEST) += memcpy_kunit.o
CFLAGS_overflow_kunit.o = $(call cc-disable-warning, tautological-constant-out-of-range-compare)
obj-$(CONFIG_OVERFLOW_KUNIT_TEST) += overflow_kunit.o
+obj-$(CONFIG_PRINTF_KUNIT_TEST) += printf_kunit.o
obj-$(CONFIG_SIPHASH_KUNIT_TEST) += siphash_kunit.o
obj-$(CONFIG_SLUB_KUNIT_TEST) += slub_kunit.o
obj-$(CONFIG_TEST_SORT) += test_sort.o
diff --git a/lib/test_printf.c b/lib/tests/printf_kunit.c
similarity index 87%
rename from lib/test_printf.c
rename to lib/tests/printf_kunit.c
index 59dbe4f9a4cb..287bbfb61148 100644
--- a/lib/test_printf.c
+++ b/lib/tests/printf_kunit.c
@@ -3,9 +3,7 @@
* Test cases for printf facility.
*/

-#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
-
-#include <linux/init.h>
+#include <kunit/test.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/printk.h>
@@ -25,8 +23,6 @@

#include <linux/property.h>

-#include "../tools/testing/selftests/kselftest_module.h"
-
#define BUF_SIZE 256
#define PAD_SIZE 16
#define FILL_CHAR '$'
@@ -37,12 +33,17 @@
block \
__diag_pop();

-KSTM_MODULE_GLOBALS();
+static unsigned int total_tests;
+
+static char *test_buffer;
+static char *alloced_buffer;
+
+static struct kunit *kunittest;

-static char *test_buffer __initdata;
-static char *alloced_buffer __initdata;
+#define tc_fail(fmt, ...) \
+ KUNIT_FAIL(kunittest, fmt, ##__VA_ARGS__)

-static int __printf(4, 0) __init
+static void __printf(4, 0)
do_test(int bufsize, const char *expect, int elen,
const char *fmt, va_list ap)
{
@@ -57,52 +58,50 @@ do_test(int bufsize, const char *expect, int elen,
va_end(aq);

if (ret != elen) {
- pr_warn("vsnprintf(buf, %d, \"%s\", ...) returned %d, expected %d\n",
+ tc_fail("vsnprintf(buf, %d, \"%s\", ...) returned %d, expected %d",
bufsize, fmt, ret, elen);
- return 1;
+ return;
}

if (memchr_inv(alloced_buffer, FILL_CHAR, PAD_SIZE)) {
- pr_warn("vsnprintf(buf, %d, \"%s\", ...) wrote before buffer\n", bufsize, fmt);
- return 1;
+ tc_fail("vsnprintf(buf, %d, \"%s\", ...) wrote before buffer",
+ bufsize, fmt);
+ return;
}

if (!bufsize) {
if (memchr_inv(test_buffer, FILL_CHAR, BUF_SIZE + PAD_SIZE)) {
- pr_warn("vsnprintf(buf, 0, \"%s\", ...) wrote to buffer\n",
- fmt);
- return 1;
+ tc_fail("vsnprintf(buf, 0, \"%s\", ...) wrote to buffer", fmt);
}
- return 0;
+ return;
}

written = min(bufsize-1, elen);
if (test_buffer[written]) {
- pr_warn("vsnprintf(buf, %d, \"%s\", ...) did not nul-terminate buffer\n",
+ tc_fail("vsnprintf(buf, %d, \"%s\", ...) did not nul-terminate buffer",
bufsize, fmt);
- return 1;
+ return;
}

if (memchr_inv(test_buffer + written + 1, FILL_CHAR, bufsize - (written + 1))) {
- pr_warn("vsnprintf(buf, %d, \"%s\", ...) wrote beyond the nul-terminator\n",
+ tc_fail("vsnprintf(buf, %d, \"%s\", ...) wrote beyond the nul-terminator",
bufsize, fmt);
- return 1;
+ return;
}

if (memchr_inv(test_buffer + bufsize, FILL_CHAR, BUF_SIZE + PAD_SIZE - bufsize)) {
- pr_warn("vsnprintf(buf, %d, \"%s\", ...) wrote beyond buffer\n", bufsize, fmt);
- return 1;
+ tc_fail("vsnprintf(buf, %d, \"%s\", ...) wrote beyond buffer", bufsize, fmt);
+ return;
}

if (memcmp(test_buffer, expect, written)) {
- pr_warn("vsnprintf(buf, %d, \"%s\", ...) wrote '%s', expected '%.*s'\n",
+ tc_fail("vsnprintf(buf, %d, \"%s\", ...) wrote '%s', expected '%.*s'",
bufsize, fmt, test_buffer, written, expect);
- return 1;
+ return;
}
- return 0;
}

-static void __printf(3, 4) __init
+static void __printf(3, 4)
__test(const char *expect, int elen, const char *fmt, ...)
{
va_list ap;
@@ -110,9 +109,8 @@ __test(const char *expect, int elen, const char *fmt, ...)
char *p;

if (elen >= BUF_SIZE) {
- pr_err("error in test suite: expected output length %d too long. Format was '%s'.\n",
- elen, fmt);
- failed_tests++;
+ tc_fail("error in test suite: expected output length %d too long. Format was '%s'.",
+ elen, fmt);
return;
}

@@ -124,19 +122,18 @@ __test(const char *expect, int elen, const char *fmt, ...)
* enough and 0), and then we also test that kvasprintf would
* be able to print it as expected.
*/
- failed_tests += do_test(BUF_SIZE, expect, elen, fmt, ap);
+ do_test(BUF_SIZE, expect, elen, fmt, ap);
rand = get_random_u32_inclusive(1, elen + 1);
/* Since elen < BUF_SIZE, we have 1 <= rand <= BUF_SIZE. */
- failed_tests += do_test(rand, expect, elen, fmt, ap);
- failed_tests += do_test(0, expect, elen, fmt, ap);
+ do_test(rand, expect, elen, fmt, ap);
+ do_test(0, expect, elen, fmt, ap);

p = kvasprintf(GFP_KERNEL, fmt, ap);
if (p) {
total_tests++;
if (memcmp(p, expect, elen+1)) {
- pr_warn("kvasprintf(..., \"%s\", ...) returned '%s', expected '%s'\n",
+ tc_fail("kvasprintf(..., \"%s\", ...) returned '%s', expected '%s'",
fmt, p, expect);
- failed_tests++;
}
kfree(p);
}
@@ -146,7 +143,7 @@ __test(const char *expect, int elen, const char *fmt, ...)
#define test(expect, fmt, ...) \
__test(expect, strlen(expect), fmt, ##__VA_ARGS__)

-static void __init
+static void
test_basic(void)
{
/* Work around annoying "warning: zero-length gnu_printf format string". */
@@ -158,7 +155,7 @@ test_basic(void)
__test("xxx\0yyy", 7, "xxx%cyyy", '\0');
}

-static void __init
+static void
test_number(void)
{
test("0x1234abcd ", "%#-12x", 0x1234abcd);
@@ -180,7 +177,7 @@ test_number(void)
test("00|0|0|0|0", "%.2d|%.1d|%.0d|%.*d|%1.0d", 0, 0, 0, 0, 0, 0);
}

-static void __init
+static void
test_string(void)
{
test("", "%s%.0s", "", "123");
@@ -218,7 +215,7 @@ test_string(void)
#define ZEROS "00000000" /* hex 32 zero bits */
#define ONES "ffffffff" /* hex 32 one bits */

-static int __init
+static int
plain_format(void)
{
char buf[PLAIN_BUF_SIZE];
@@ -230,7 +227,7 @@ plain_format(void)
return -1;

if (strncmp(buf, PTR_VAL_NO_CRNG, PTR_WIDTH) == 0) {
- pr_warn("crng possibly not yet initialized. plain 'p' buffer contains \"%s\"",
+ kunit_warn(kunittest, "crng possibly not yet initialized. plain 'p' buffer contains \"%s\"",
PTR_VAL_NO_CRNG);
return 0;
}
@@ -250,7 +247,7 @@ plain_format(void)
#define ZEROS ""
#define ONES ""

-static int __init
+static int
plain_format(void)
{
/* Format is implicitly tested for 32 bit machines by plain_hash() */
@@ -259,7 +256,7 @@ plain_format(void)

#endif /* BITS_PER_LONG == 64 */

-static int __init
+static int
plain_hash_to_buffer(const void *p, char *buf, size_t len)
{
int nchars;
@@ -270,7 +267,7 @@ plain_hash_to_buffer(const void *p, char *buf, size_t len)
return -1;

if (strncmp(buf, PTR_VAL_NO_CRNG, PTR_WIDTH) == 0) {
- pr_warn("crng possibly not yet initialized. plain 'p' buffer contains \"%s\"",
+ kunit_warn(kunittest, "crng possibly not yet initialized. plain 'p' buffer contains \"%s\"",
PTR_VAL_NO_CRNG);
return 0;
}
@@ -278,7 +275,7 @@ plain_hash_to_buffer(const void *p, char *buf, size_t len)
return 0;
}

-static int __init
+static int
plain_hash(void)
{
char buf[PLAIN_BUF_SIZE];
@@ -298,32 +295,29 @@ plain_hash(void)
* We can't use test() to test %p because we don't know what output to expect
* after an address is hashed.
*/
-static void __init
+static void
plain(void)
{
int err;

if (no_hash_pointers) {
- pr_warn("skipping plain 'p' tests");
- skipped_tests += 2;
+ kunit_warn(kunittest, "skipping plain 'p' tests");
return;
}

err = plain_hash();
if (err) {
- pr_warn("plain 'p' does not appear to be hashed\n");
- failed_tests++;
+ tc_fail("plain 'p' does not appear to be hashed");
return;
}

err = plain_format();
if (err) {
- pr_warn("hashing plain 'p' has unexpected format\n");
- failed_tests++;
+ tc_fail("hashing plain 'p' has unexpected format");
}
}

-static void __init
+static void
test_hashed(const char *fmt, const void *p)
{
char buf[PLAIN_BUF_SIZE];
@@ -343,7 +337,7 @@ test_hashed(const char *fmt, const void *p)
/*
* NULL pointers aren't hashed.
*/
-static void __init
+static void
null_pointer(void)
{
test(ZEROS "00000000", "%p", NULL);
@@ -354,7 +348,7 @@ null_pointer(void)
/*
* Error pointers aren't hashed.
*/
-static void __init
+static void
error_pointer(void)
{
test(ONES "fffffff5", "%p", ERR_PTR(-11));
@@ -364,7 +358,7 @@ error_pointer(void)

#define PTR_INVALID ((void *)0x000000ab)

-static void __init
+static void
invalid_pointer(void)
{
test_hashed("%p", PTR_INVALID);
@@ -372,18 +366,18 @@ invalid_pointer(void)
test("(efault)", "%pE", PTR_INVALID);
}

-static void __init
+static void
symbol_ptr(void)
{
}

-static void __init
+static void
kernel_ptr(void)
{
/* We can't test this without access to kptr_restrict. */
}

-static void __init
+static void
struct_resource(void)
{
struct resource test_resource = {
@@ -432,7 +426,7 @@ struct_resource(void)
"%pR", &test_resource);
}

-static void __init
+static void
struct_range(void)
{
struct range test_range = DEFINE_RANGE(0xc0ffee00ba5eba11,
@@ -448,17 +442,17 @@ struct_range(void)
"%pra", &test_range);
}

-static void __init
+static void
addr(void)
{
}

-static void __init
+static void
escaped_str(void)
{
}

-static void __init
+static void
hex_string(void)
{
const char buf[3] = {0xc0, 0xff, 0xee};
@@ -469,7 +463,7 @@ hex_string(void)
"%*ph|%*phC|%*phD|%*phN", 3, buf, 3, buf, 3, buf, 3, buf);
}

-static void __init
+static void
mac(void)
{
const u8 addr[6] = {0x2d, 0x48, 0xd6, 0xfc, 0x7a, 0x05};
@@ -481,7 +475,7 @@ mac(void)
test("057afcd6482d", "%pmR", addr);
}

-static void __init
+static void
ip4(void)
{
struct sockaddr_in sa;
@@ -496,19 +490,19 @@ ip4(void)
test("001.002.003.004:12345|1.2.3.4:12345", "%piSp|%pISp", &sa, &sa);
}

-static void __init
+static void
ip6(void)
{
}

-static void __init
+static void
ip(void)
{
ip4();
ip6();
}

-static void __init
+static void
uuid(void)
{
const char uuid[16] = {0x0, 0x1, 0x2, 0x3, 0x4, 0x5, 0x6, 0x7,
@@ -520,7 +514,7 @@ uuid(void)
test("03020100-0504-0706-0809-0A0B0C0D0E0F", "%pUL", uuid);
}

-static struct dentry test_dentry[4] __initdata = {
+static struct dentry test_dentry[4] = {
{ .d_parent = &test_dentry[0],
.d_name = QSTR_INIT(test_dentry[0].d_iname, 3),
.d_iname = "foo" },
@@ -535,7 +529,7 @@ static struct dentry test_dentry[4] __initdata = {
.d_iname = "romeo" },
};

-static void __init
+static void
dentry(void)
{
test("foo", "%pd", &test_dentry[0]);
@@ -556,12 +550,12 @@ dentry(void)
test(" bravo/alfa| bravo/alfa", "%12pd2|%*pd2", &test_dentry[2], 12, &test_dentry[2]);
}

-static void __init
+static void
struct_va_format(void)
{
}

-static void __init
+static void
time_and_date(void)
{
/* 1543210543 */
@@ -595,12 +589,12 @@ time_and_date(void)
test("15:32:23|0119-00-04", "%ptTtrs|%ptTdrs", &t, &t);
}

-static void __init
+static void
struct_clk(void)
{
}

-static void __init
+static void
large_bitmap(void)
{
const int nbits = 1 << 16;
@@ -614,7 +608,7 @@ large_bitmap(void)
bitmap_free(bits);
}

-static void __init
+static void
bitmap(void)
{
DECLARE_BITMAP(bits, 20);
@@ -637,7 +631,7 @@ bitmap(void)
large_bitmap();
}

-static void __init
+static void
netdev_features(void)
{
}
@@ -663,7 +657,7 @@ static const struct page_flags_test pft[] = {
"%#x", "kasantag"},
};

-static void __init
+static void
page_flags_test(int section, int node, int zone, int last_cpupid,
int kasan_tag, unsigned long flags, const char *name,
char *cmp_buf)
@@ -701,7 +695,7 @@ page_flags_test(int section, int node, int zone, int last_cpupid,
test(cmp_buf, "%pGp", &flags);
}

-static void __init
+static void
flags(void)
{
unsigned long flags;
@@ -749,7 +743,7 @@ flags(void)
kfree(cmp_buffer);
}

-static void __init fwnode_pointer(void)
+static void fwnode_pointer(void)
{
const struct software_node first = { .name = "first" };
const struct software_node second = { .name = "second", .parent = &first };
@@ -763,7 +757,7 @@ static void __init fwnode_pointer(void)

rval = software_node_register_node_group(group);
if (rval) {
- pr_warn("cannot register softnodes; rval %d\n", rval);
+ kunit_warn(kunittest, "cannot register softnodes; rval %d", rval);
return;
}

@@ -776,7 +770,7 @@ static void __init fwnode_pointer(void)
software_node_unregister_node_group(group);
}

-static void __init fourcc_pointer(void)
+static void fourcc_pointer(void)
{
struct {
u32 code;
@@ -793,7 +787,7 @@ static void __init fourcc_pointer(void)
test(try[i].str, "%p4cc", &try[i].code);
}

-static void __init
+static void
errptr(void)
{
test("-1234", "%pe", ERR_PTR(-1234));
@@ -813,7 +807,7 @@ errptr(void)
#endif
}

-static void __init
+static void
test_pointer(void)
{
plain();
@@ -842,13 +836,15 @@ test_pointer(void)
fourcc_pointer();
}

-static void __init selftest(void)
+static void printf_test(struct kunit *test)
{
alloced_buffer = kmalloc(BUF_SIZE + 2*PAD_SIZE, GFP_KERNEL);
if (!alloced_buffer)
return;
test_buffer = alloced_buffer + PAD_SIZE;

+ kunittest = test;
+
test_basic();
test_number();
test_string();
@@ -857,7 +853,31 @@ static void __init selftest(void)
kfree(alloced_buffer);
}

-KSTM_MODULE_LOADERS(test_printf);
+static int printf_suite_init(struct kunit_suite *suite)
+{
+ total_tests = 0;
+ return 0;
+}
+
+static void printf_suite_exit(struct kunit_suite *suite)
+{
+ kunit_info(suite, "ran %u tests", total_tests);
+}
+
+static struct kunit_case printf_test_cases[] = {
+ KUNIT_CASE(printf_test),
+ {}
+};
+
+static struct kunit_suite printf_test_suite = {
+ .name = "printf",
+ .suite_init = printf_suite_init,
+ .suite_exit = printf_suite_exit,
+ .test_cases = printf_test_cases,
+};
+
+kunit_test_suite(printf_test_suite);
+
MODULE_AUTHOR("Rasmus Villemoes <linux@rasmusvillemoes.dk>");
MODULE_DESCRIPTION("Test cases for printf facility");
MODULE_LICENSE("GPL");
diff --git a/tools/testing/selftests/lib/config b/tools/testing/selftests/lib/config
index 306a3d4dca98..f4b4b8822241 100644
--- a/tools/testing/selftests/lib/config
+++ b/tools/testing/selftests/lib/config
@@ -1,4 +1,3 @@
-CONFIG_TEST_PRINTF=m
CONFIG_TEST_SCANF=m
CONFIG_TEST_BITMAP=m
CONFIG_TEST_BITOPS=m
diff --git a/tools/testing/selftests/lib/printf.sh b/tools/testing/selftests/lib/printf.sh
deleted file mode 100755
index 05f4544e87f9..000000000000
--- a/tools/testing/selftests/lib/printf.sh
+++ /dev/null
@@ -1,4 +0,0 @@
-#!/bin/sh
-# SPDX-License-Identifier: GPL-2.0
-# Tests the printf infrastructure using test_printf kernel module.
-$(dirname $0)/../kselftest/module.sh "printf" test_printf

--
2.48.1