[PATCH v2 03/14] kunit: Add test cases for backtrace warning suppression

From: Guenter Roeck <linux@roeck-us.net>
To: linux-kselftest@vger.kernel.org
Cc: "David Airlie" <airlied@gmail.com>,
	"Arnd Bergmann" <arnd@arndb.de>,
	"Maíra Canal" <mcanal@igalia.com>,
	"Dan Carpenter" <dan.carpenter@linaro.org>,
	"Kees Cook" <keescook@chromium.org>,
	"Daniel Diaz" <daniel.diaz@linaro.org>,
	"David Gow" <davidgow@google.com>,
	"Arthur Grillo" <arthurgrillo@riseup.net>,
	"Brendan Higgins" <brendan.higgins@linux.dev>,
	"Naresh Kamboju" <naresh.kamboju@linaro.org>,
	"Maarten Lankhorst" <maarten.lankhorst@linux.intel.com>,
	"Andrew Morton" <akpm@linux-foundation.org>,
	"Maxime Ripard" <mripard@kernel.org>,
	"Ville Syrjälä" <ville.syrjala@linux.intel.com>,
	"Daniel Vetter" <daniel@ffwll.ch>,
	"Thomas Zimmermann" <tzimmermann@suse.de>,
	dri-devel@lists.freedesktop.org, kunit-dev@googlegroups.com,
	linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
	linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org,
	linux-sh@vger.kernel.org, loongarch@lists.linux.dev,
	netdev@vger.kernel.org, "Guenter Roeck" <linux@roeck-us.net>,
	"Linux Kernel Functional Testing" <lkft@linaro.org>
Subject: [PATCH v2 03/14] kunit: Add test cases for backtrace warning suppression
Date: Mon, 25 Mar 2024 10:52:37 -0700	[thread overview]
Message-ID: <20240325175248.1499046-4-linux@roeck-us.net> (raw)
In-Reply-To: <20240325175248.1499046-1-linux@roeck-us.net>

Add unit tests to verify that warning backtrace suppression works.

If backtrace suppression does _not_ work, the unit tests will likely
trigger unsuppressed backtraces, which should actually help to get
the affected architectures / platforms fixed.

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>
---
- Rebased to v6.9-rc1
- Added Tested-by:, Acked-by:, and Reviewed-by: tags
- Introduced KUNIT_SUPPRESS_BACKTRACE configuration option

 lib/kunit/Makefile                     |   7 +-
 lib/kunit/backtrace-suppression-test.c | 104 +++++++++++++++++++++++++
 2 files changed, 109 insertions(+), 2 deletions(-)
 create mode 100644 lib/kunit/backtrace-suppression-test.c

diff --git a/lib/kunit/Makefile b/lib/kunit/Makefile
index 545b57c3be48..3eee1bd0ce5e 100644
--- a/lib/kunit/Makefile
+++ b/lib/kunit/Makefile
@@ -16,10 +16,13 @@ endif
 
 # KUnit 'hooks' and bug handling are built-in even when KUnit is built
 # as a module.
-obj-y +=				hooks.o \
-					bug.o
+obj-y +=				hooks.o
+obj-$(CONFIG_KUNIT_SUPPRESS_BACKTRACE) += bug.o
 
 obj-$(CONFIG_KUNIT_TEST) +=		kunit-test.o
+ifeq ($(CCONFIG_KUNIT_SUPPRESS_BACKTRACE),y)
+obj-$(CONFIG_KUNIT_TEST) +=		backtrace-suppression-test.o
+endif
 
 # string-stream-test compiles built-in only.
 ifeq ($(CONFIG_KUNIT_TEST),y)
diff --git a/lib/kunit/backtrace-suppression-test.c b/lib/kunit/backtrace-suppression-test.c
new file mode 100644
index 000000000000..47c619283802
--- /dev/null
+++ b/lib/kunit/backtrace-suppression-test.c
@@ -0,0 +1,104 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * KUnit test for suppressing warning tracebacks
+ *
+ * Copyright (C) 2024, Guenter Roeck
+ * Author: Guenter Roeck <linux@roeck-us.net>
+ */
+
+#include <kunit/test.h>
+#include <linux/bug.h>
+
+static void backtrace_suppression_test_warn_direct(struct kunit *test)
+{
+	DEFINE_SUPPRESSED_WARNING(backtrace_suppression_test_warn_direct);
+
+	START_SUPPRESSED_WARNING(backtrace_suppression_test_warn_direct);
+	WARN(1, "This backtrace should be suppressed");
+	END_SUPPRESSED_WARNING(backtrace_suppression_test_warn_direct);
+
+	KUNIT_EXPECT_EQ(test, SUPPRESSED_WARNING_COUNT(backtrace_suppression_test_warn_direct), 1);
+}
+
+static void trigger_backtrace_warn(void)
+{
+	WARN(1, "This backtrace should be suppressed");
+}
+
+static void backtrace_suppression_test_warn_indirect(struct kunit *test)
+{
+	DEFINE_SUPPRESSED_WARNING(trigger_backtrace_warn);
+
+	START_SUPPRESSED_WARNING(trigger_backtrace_warn);
+	trigger_backtrace_warn();
+	END_SUPPRESSED_WARNING(trigger_backtrace_warn);
+
+	KUNIT_EXPECT_EQ(test, SUPPRESSED_WARNING_COUNT(trigger_backtrace_warn), 1);
+}
+
+static void backtrace_suppression_test_warn_multi(struct kunit *test)
+{
+	DEFINE_SUPPRESSED_WARNING(trigger_backtrace_warn);
+	DEFINE_SUPPRESSED_WARNING(backtrace_suppression_test_warn_multi);
+
+	START_SUPPRESSED_WARNING(backtrace_suppression_test_warn_multi);
+	START_SUPPRESSED_WARNING(trigger_backtrace_warn);
+	WARN(1, "This backtrace should be suppressed");
+	trigger_backtrace_warn();
+	END_SUPPRESSED_WARNING(trigger_backtrace_warn);
+	END_SUPPRESSED_WARNING(backtrace_suppression_test_warn_multi);
+
+	KUNIT_EXPECT_EQ(test, SUPPRESSED_WARNING_COUNT(backtrace_suppression_test_warn_multi), 1);
+	KUNIT_EXPECT_EQ(test, SUPPRESSED_WARNING_COUNT(trigger_backtrace_warn), 1);
+}
+
+static void backtrace_suppression_test_warn_on_direct(struct kunit *test)
+{
+	DEFINE_SUPPRESSED_WARNING(backtrace_suppression_test_warn_on_direct);
+
+	if (!IS_ENABLED(CONFIG_DEBUG_BUGVERBOSE) && !IS_ENABLED(CONFIG_KALLSYMS))
+		kunit_skip(test, "requires CONFIG_DEBUG_BUGVERBOSE or CONFIG_KALLSYMS");
+
+	START_SUPPRESSED_WARNING(backtrace_suppression_test_warn_on_direct);
+	WARN_ON(1);
+	END_SUPPRESSED_WARNING(backtrace_suppression_test_warn_on_direct);
+
+	KUNIT_EXPECT_EQ(test,
+			SUPPRESSED_WARNING_COUNT(backtrace_suppression_test_warn_on_direct), 1);
+}
+
+static void trigger_backtrace_warn_on(void)
+{
+	WARN_ON(1);
+}
+
+static void backtrace_suppression_test_warn_on_indirect(struct kunit *test)
+{
+	DEFINE_SUPPRESSED_WARNING(trigger_backtrace_warn_on);
+
+	if (!IS_ENABLED(CONFIG_DEBUG_BUGVERBOSE))
+		kunit_skip(test, "requires CONFIG_DEBUG_BUGVERBOSE");
+
+	START_SUPPRESSED_WARNING(trigger_backtrace_warn_on);
+	trigger_backtrace_warn_on();
+	END_SUPPRESSED_WARNING(trigger_backtrace_warn_on);
+
+	KUNIT_EXPECT_EQ(test, SUPPRESSED_WARNING_COUNT(trigger_backtrace_warn_on), 1);
+}
+
+static struct kunit_case backtrace_suppression_test_cases[] = {
+	KUNIT_CASE(backtrace_suppression_test_warn_direct),
+	KUNIT_CASE(backtrace_suppression_test_warn_indirect),
+	KUNIT_CASE(backtrace_suppression_test_warn_multi),
+	KUNIT_CASE(backtrace_suppression_test_warn_on_direct),
+	KUNIT_CASE(backtrace_suppression_test_warn_on_indirect),
+	{}
+};
+
+static struct kunit_suite backtrace_suppression_test_suite = {
+	.name = "backtrace-suppression-test",
+	.test_cases = backtrace_suppression_test_cases,
+};
+kunit_test_suites(&backtrace_suppression_test_suite);
+
+MODULE_LICENSE("GPL");
-- 
2.39.2

