On Wed, 3 Apr 2024 at 21:19, Guenter Roeck <linux@roeck-us.net> wrote:
>
> 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>
> ---

There's a typo in the Makefile, which stops this from being built at
all. Otherwise, it seems good to me.

-- David

> v2:
> - Rebased to v6.9-rc1
> - Added Tested-by:, Acked-by:, and Reviewed-by: tags
> - Introduced KUNIT_SUPPRESS_BACKTRACE configuration option
> v3:
> - Rebased to v6.9-rc2
>
>  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)

s/CCONFIG_/CONFIG_/ ?




> +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
>