patches/old/kunit-add-documentation-for-warning-backtrace-suppression-api.patch

From: Guenter Roeck <linux@roeck-us.net>
Subject: kunit: add documentation for warning backtrace suppression API
Date: Thu, 13 Mar 2025 11:43:19 +0000

Document API functions for suppressing warning backtraces.

Link: https://lkml.kernel.org/r/20250313114329.284104-5-acarmina@redhat.com
Signed-off-by: Alessandro Carminati <acarmina@redhat.com>
Tested-by: Linux Kernel Functional Testing <lkft@linaro.org>
Acked-by: Dan Carpenter <dan.carpenter@linaro.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: David Gow <davidgow@google.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Arthur Grillo <arthurgrillo@riseup.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brendan Higgins <brendan.higgins@linux.dev>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Charlie Jenkins <charlie@rivosinc.com>
Cc: Daniel Diaz <daniel.diaz@linaro.org>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Dave Airlie <airlied@gmail.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maíra Canal <mcanal@igalia.com>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Naresh Kamboju <naresh.kamboju@linaro.org>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Rae Moar <rmoar@google.com>
Cc: Rich Felker <dalias@libc.org>
Cc: Simon Horman <horms@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Thomas Zimemrmann <tzimmermann@suse.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 Documentation/dev-tools/kunit/usage.rst |   30 +++++++++++++++++++++-
 1 file changed, 29 insertions(+), 1 deletion(-)

--- a/Documentation/dev-tools/kunit/usage.rst~kunit-add-documentation-for-warning-backtrace-suppression-api
+++ a/Documentation/dev-tools/kunit/usage.rst
@@ -157,6 +157,34 @@ Alternatively, one can take full control
 	if (some_setup_function())
 		KUNIT_FAIL(test, "Failed to setup thing for testing");
 
+Suppressing warning backtraces
+------------------------------
+
+Some unit tests trigger warning backtraces either intentionally or as side
+effect. Such backtraces are normally undesirable since they distract from
+the actual test and may result in the impression that there is a problem.
+
+Such backtraces can be suppressed. To suppress a backtrace in some_function(),
+use the following code.
+
+.. code-block:: c
+
+	static void some_test(struct kunit *test)
+	{
+		DEFINE_SUPPRESSED_WARNING(some_function);
+
+		KUNIT_START_SUPPRESSED_WARNING(some_function);
+		trigger_backtrace();
+		KUNIT_END_SUPPRESSED_WARNING(some_function);
+	}
+
+SUPPRESSED_WARNING_COUNT() returns the number of suppressed backtraces. If the
+suppressed backtrace was triggered on purpose, this can be used to check if
+the backtrace was actually triggered.
+
+.. code-block:: c
+
+	KUNIT_EXPECT_EQ(test, SUPPRESSED_WARNING_COUNT(some_function), 1);
 
 Test Suites
 ~~~~~~~~~~~
@@ -857,4 +885,4 @@ For example:
 		dev_managed_string = devm_kstrdup(fake_device, "Hello, World!");
 
 		// Everything is cleaned up automatically when the test ends.
-	}
\ No newline at end of file
+	}
_