printf: convert self-test to KUnit

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>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Tested-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20250307-printf-kunit-convert-v6-1-4d85c361c241@gmail.com
Signed-off-by: Kees Cook <kees@kernel.org>

Author: tamird

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.

Documentation/dev-tools/kselftest.rst

@@ -347,7 +347,7 @@ kselftest.  We use kselftests for lib/ as an example.
 1. Create the test module
 
 2. Create the test script that will run (load/unload) the module
-   e.g. ``tools/testing/selftests/lib/printf.sh``
+   e.g. ``tools/testing/selftests/lib/bitmap.sh``
 
 3. Add line to config file e.g. ``tools/testing/selftests/lib/config``
 

MAINTAINERS

@@ -25411,8 +25411,8 @@ 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

lib/Kconfig.debug

@@ -2427,6 +2427,15 @@ 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
@@ -2440,9 +2449,6 @@ 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"
 

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

lib/tests/Makefile

@@ -29,6 +29,7 @@ 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