[PATCH v2 0/2] kunit: add boot time parameter to enable KUnit

[PATCH v2 0/2] kunit: add boot time parameter to enable KUnit

[Joe Fradley]

v2:
 - Added enable check in executor.c to prevent wrong error output from
   kunit_tool.py when run against a KUnit disabled kernel
 - kunit_tool.py now passes kunit.enable=1
 - Flipped around logic of new config to KUNIT_DEFAULT_ENABLED
 - Now load modules containing tests but not executing them
 - Various message/description text clean up

There are some use cases where the kernel binary is desired to be the same
for both production and testing. This poses a problem for users of KUnit
as built-in tests will automatically run at startup and test modules
can still be loaded leaving the kernel in an unsafe state. There is a
"test" taint flag that gets set if a test runs but nothing to prevent
the execution.

This patch adds the kunit.enable module parameter that will need to be
set to true in addition to KUNIT being enabled for KUnit tests to run.
The default value is true giving backwards compatibility. However, for
the production+testing use case the new config option KUNIT_DEFAULT_ENABLED
can be set to N requiring the tester to opt-in by passing kunit.enable=1 to
the kernel.

Joe Fradley (2):
  kunit: add kunit.enable to enable/disable KUnit test
  kunit: no longer call module_info(test, "Y") for kunit modules

 .../admin-guide/kernel-parameters.txt         |  6 +++++
 include/kunit/test.h                          |  3 ++-
 lib/kunit/Kconfig                             | 11 +++++++++
 lib/kunit/executor.c                          |  4 ++++
 lib/kunit/test.c                              | 24 +++++++++++++++++++
 tools/testing/kunit/kunit_kernel.py           |  1 +
 6 files changed, 48 insertions(+), 1 deletion(-)

-- 
2.37.1.595.g718a3a8f04-goog

[PATCH v2 1/2] kunit: add kunit.enable to enable/disable KUnit test

[Joe Fradley]

This patch adds the kunit.enable module parameter that will need to be
set to true in addition to KUNIT being enabled for KUnit tests to run.
The default value is true giving backwards compatibility. However, for
the production+testing use case the new config option
KUNIT_DEFAULT_ENABLED can be set to N requiring the tester to opt-in
by passing kunit.enable=1 to the kernel.

Signed-off-by: Joe Fradley <joefradley@google.com>
---
Changes since v1:
- Created a function to get kunit enable state
- Check kunit enable state in kunit_run_all_tests() in executor.c
- Load test module even if KUnit is disabled but still don't execute
  tests
- Simplified kunit disable message and kunit.enable parameter
  description
- Flipped around logic of new config to be KUNIT_DEFAULT_ENABLED
- kunit_tool.py now passes kunit.enable=1 to kernel

 .../admin-guide/kernel-parameters.txt         |  6 +++++
 include/kunit/test.h                          |  2 ++
 lib/kunit/Kconfig                             | 11 +++++++++
 lib/kunit/executor.c                          |  4 ++++
 lib/kunit/test.c                              | 24 +++++++++++++++++++
 tools/testing/kunit/kunit_kernel.py           |  1 +
 6 files changed, 48 insertions(+)

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index adfda56b2691..7aa3abd7f1c5 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -2432,6 +2432,12 @@
 			0: force disabled
 			1: force enabled
 
+	kunit.enable=	[KUNIT] Enable executing KUnit tests. Requires
+			CONFIG_KUNIT to be set to be fully enabled. The
+			default value can be overridden via
+			KUNIT_DEFAULT_ENABLED.
+			Default is 1 (enabled)
+
 	kvm.ignore_msrs=[KVM] Ignore guest accesses to unhandled MSRs.
 			Default is 0 (don't ignore, but inject #GP)
 
diff --git a/include/kunit/test.h b/include/kunit/test.h
index c958855681cc..ee6bf4ecbd89 100644
--- a/include/kunit/test.h
+++ b/include/kunit/test.h
@@ -228,6 +228,8 @@ static inline void kunit_set_failure(struct kunit *test)
 	WRITE_ONCE(test->status, KUNIT_FAILURE);
 }
 
+bool kunit_enabled(void);
+
 void kunit_init_test(struct kunit *test, const char *name, char *log);
 
 int kunit_run_tests(struct kunit_suite *suite);
diff --git a/lib/kunit/Kconfig b/lib/kunit/Kconfig
index 0b5dfb001bac..626719b95bad 100644
--- a/lib/kunit/Kconfig
+++ b/lib/kunit/Kconfig
@@ -59,4 +59,15 @@ config KUNIT_ALL_TESTS
 
 	  If unsure, say N.
 
+config KUNIT_DEFAULT_ENABLED
+	bool "Default value of kunit.enable"
+	default y
+	help
+	  Sets the default value of kunit.enable. If set to N then KUnit
+	  tests will not execute unless kunit.enable=1 is passed to the
+	  kernel command line.
+
+	  In most cases this should be left as Y. Only if additional opt-in
+	  behavior is needed should this be set to N.
+
 endif # KUNIT
diff --git a/lib/kunit/executor.c b/lib/kunit/executor.c
index 5e223327196a..9bbc422c284b 100644
--- a/lib/kunit/executor.c
+++ b/lib/kunit/executor.c
@@ -190,6 +190,10 @@ int kunit_run_all_tests(void)
 {
 	struct suite_set suite_set = {__kunit_suites_start, __kunit_suites_end};
 	int err = 0;
+	if (!kunit_enabled()) {
+		pr_info("kunit: disabled\n");
+		goto out;
+	}
 
 	if (filter_glob_param) {
 		suite_set = kunit_filter_suites(&suite_set, filter_glob_param, &err);
diff --git a/lib/kunit/test.c b/lib/kunit/test.c
index b73d5bb5c473..1e54373309a4 100644
--- a/lib/kunit/test.c
+++ b/lib/kunit/test.c
@@ -54,6 +54,17 @@ void __kunit_fail_current_test(const char *file, int line, const char *fmt, ...)
 EXPORT_SYMBOL_GPL(__kunit_fail_current_test);
 #endif
 
+/*
+ * Enable KUnit tests to run.
+ */
+#ifdef CONFIG_KUNIT_DEFAULT_ENABLED
+static bool enable_param = true;
+#else
+static bool enable_param;
+#endif
+module_param_named(enable, enable_param, bool, 0);
+MODULE_PARM_DESC(enable, "Enable KUnit tests");
+
 /*
  * KUnit statistic mode:
  * 0 - disabled
@@ -586,10 +597,20 @@ static void kunit_init_suite(struct kunit_suite *suite)
 	suite->suite_init_err = 0;
 }
 
+bool kunit_enabled(void)
+{
+	return enable_param;
+}
+
 int __kunit_test_suites_init(struct kunit_suite * const * const suites, int num_suites)
 {
 	unsigned int i;
 
+	if (!kunit_enabled() && num_suites > 0) {
+		pr_info("kunit: disabled\n");
+		return 0;
+	}
+
 	for (i = 0; i < num_suites; i++) {
 		kunit_init_suite(suites[i]);
 		kunit_run_tests(suites[i]);
@@ -607,6 +628,9 @@ void __kunit_test_suites_exit(struct kunit_suite **suites, int num_suites)
 {
 	unsigned int i;
 
+	if (!kunit_enabled())
+		return;
+
 	for (i = 0; i < num_suites; i++)
 		kunit_exit_suite(suites[i]);
 
diff --git a/tools/testing/kunit/kunit_kernel.py b/tools/testing/kunit/kunit_kernel.py
index f5c26ea89714..ef794da420d7 100644
--- a/tools/testing/kunit/kunit_kernel.py
+++ b/tools/testing/kunit/kunit_kernel.py
@@ -359,6 +359,7 @@ class LinuxSourceTree:
 			args = []
 		if filter_glob:
 			args.append('kunit.filter_glob='+filter_glob)
+		args.append('kunit.enable=1')
 
 		process = self._ops.start(args, build_dir)
 		assert process.stdout is not None  # tell mypy it's set
-- 
2.37.1.595.g718a3a8f04-goog

Re: [PATCH v2 1/2] kunit: add kunit.enable to enable/disable KUnit test

[David Gow]

[-- Attachment #1: Type: text/plain, Size: 7451 bytes --]

On Tue, Aug 23, 2022 at 10:25 PM 'Joe Fradley' via KUnit Development
<kunit-dev@googlegroups.com> wrote:
>
> This patch adds the kunit.enable module parameter that will need to be
> set to true in addition to KUNIT being enabled for KUnit tests to run.
> The default value is true giving backwards compatibility. However, for
> the production+testing use case the new config option
> KUNIT_DEFAULT_ENABLED can be set to N requiring the tester to opt-in
> by passing kunit.enable=1 to the kernel.
>
> Signed-off-by: Joe Fradley <joefradley@google.com>
> ---

Thanks very much. This looks good to me, and works on my machine.

I've put a few comments/ideas below, but none of them feel necessary to me.

Regardless, this is
Reviewed-by: David Gow <davidgow@google.com>

Cheers,
-- David

> Changes since v1:
> - Created a function to get kunit enable state
> - Check kunit enable state in kunit_run_all_tests() in executor.c
> - Load test module even if KUnit is disabled but still don't execute
>   tests
> - Simplified kunit disable message and kunit.enable parameter
>   description
> - Flipped around logic of new config to be KUNIT_DEFAULT_ENABLED
> - kunit_tool.py now passes kunit.enable=1 to kernel
>
>  .../admin-guide/kernel-parameters.txt         |  6 +++++
>  include/kunit/test.h                          |  2 ++
>  lib/kunit/Kconfig                             | 11 +++++++++
>  lib/kunit/executor.c                          |  4 ++++
>  lib/kunit/test.c                              | 24 +++++++++++++++++++
>  tools/testing/kunit/kunit_kernel.py           |  1 +
>  6 files changed, 48 insertions(+)
>
> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> index adfda56b2691..7aa3abd7f1c5 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt
> @@ -2432,6 +2432,12 @@
>                         0: force disabled
>                         1: force enabled
>
> +       kunit.enable=   [KUNIT] Enable executing KUnit tests. Requires
> +                       CONFIG_KUNIT to be set to be fully enabled. The
> +                       default value can be overridden via
> +                       KUNIT_DEFAULT_ENABLED.
> +                       Default is 1 (enabled)
> +
>         kvm.ignore_msrs=[KVM] Ignore guest accesses to unhandled MSRs.
>                         Default is 0 (don't ignore, but inject #GP)
>
> diff --git a/include/kunit/test.h b/include/kunit/test.h
> index c958855681cc..ee6bf4ecbd89 100644
> --- a/include/kunit/test.h
> +++ b/include/kunit/test.h
> @@ -228,6 +228,8 @@ static inline void kunit_set_failure(struct kunit *test)
>         WRITE_ONCE(test->status, KUNIT_FAILURE);
>  }
>
> +bool kunit_enabled(void);
> +

This probably isn't strictly necessary at this stage, given that it
just checks one variable. That being said, I don't think it hurts (and
personally, I quite like it), and find it more future-proof than
exposing the variable more widely anyway.

>  void kunit_init_test(struct kunit *test, const char *name, char *log);
>
>  int kunit_run_tests(struct kunit_suite *suite);
> diff --git a/lib/kunit/Kconfig b/lib/kunit/Kconfig
> index 0b5dfb001bac..626719b95bad 100644
> --- a/lib/kunit/Kconfig
> +++ b/lib/kunit/Kconfig
> @@ -59,4 +59,15 @@ config KUNIT_ALL_TESTS
>
>           If unsure, say N.
>
> +config KUNIT_DEFAULT_ENABLED
> +       bool "Default value of kunit.enable"
> +       default y
> +       help
> +         Sets the default value of kunit.enable. If set to N then KUnit
> +         tests will not execute unless kunit.enable=1 is passed to the
> +         kernel command line.
> +
> +         In most cases this should be left as Y. Only if additional opt-in
> +         behavior is needed should this be set to N.
> +
>  endif # KUNIT
> diff --git a/lib/kunit/executor.c b/lib/kunit/executor.c
> index 5e223327196a..9bbc422c284b 100644
> --- a/lib/kunit/executor.c
> +++ b/lib/kunit/executor.c
> @@ -190,6 +190,10 @@ int kunit_run_all_tests(void)
>  {
>         struct suite_set suite_set = {__kunit_suites_start, __kunit_suites_end};
>         int err = 0;
> +       if (!kunit_enabled()) {
> +               pr_info("kunit: disabled\n");
> +               goto out;
> +       }
>
>         if (filter_glob_param) {
>                 suite_set = kunit_filter_suites(&suite_set, filter_glob_param, &err);
> diff --git a/lib/kunit/test.c b/lib/kunit/test.c
> index b73d5bb5c473..1e54373309a4 100644
> --- a/lib/kunit/test.c
> +++ b/lib/kunit/test.c
> @@ -54,6 +54,17 @@ void __kunit_fail_current_test(const char *file, int line, const char *fmt, ...)
>  EXPORT_SYMBOL_GPL(__kunit_fail_current_test);
>  #endif
>
> +/*
> + * Enable KUnit tests to run.
> + */
> +#ifdef CONFIG_KUNIT_DEFAULT_ENABLED
> +static bool enable_param = true;
> +#else
> +static bool enable_param;
> +#endif
> +module_param_named(enable, enable_param, bool, 0);
> +MODULE_PARM_DESC(enable, "Enable KUnit tests");
> +
>  /*
>   * KUnit statistic mode:
>   * 0 - disabled
> @@ -586,10 +597,20 @@ static void kunit_init_suite(struct kunit_suite *suite)
>         suite->suite_init_err = 0;
>  }
>
> +bool kunit_enabled(void)
> +{
> +       return enable_param;
> +}
> +
>  int __kunit_test_suites_init(struct kunit_suite * const * const suites, int num_suites)
>  {
>         unsigned int i;
>
> +       if (!kunit_enabled() && num_suites > 0) {
> +               pr_info("kunit: disabled\n");

_Maybe_ this could be pr_info_once(), if you were worried about spam
(if a whole bunch of test modules were loaded at once). That being
said, I prefer it as-is, as I don't think there are a lot of cases
where large number of kunit test modules are loaded on a system with
KUnit disable. And I'm liable to forget that KUnit is disabled if a
system has been running for a while (and maybe one test module was
loaded a boot), and end up wondering why my test isn't running.

So, I'm all for leaving this as-is, personally.

> +               return 0;
> +       }
> +
>         for (i = 0; i < num_suites; i++) {
>                 kunit_init_suite(suites[i]);
>                 kunit_run_tests(suites[i]);
> @@ -607,6 +628,9 @@ void __kunit_test_suites_exit(struct kunit_suite **suites, int num_suites)
>  {
>         unsigned int i;
>
> +       if (!kunit_enabled())
> +               return;
> +
>         for (i = 0; i < num_suites; i++)
>                 kunit_exit_suite(suites[i]);
>
> diff --git a/tools/testing/kunit/kunit_kernel.py b/tools/testing/kunit/kunit_kernel.py
> index f5c26ea89714..ef794da420d7 100644
> --- a/tools/testing/kunit/kunit_kernel.py
> +++ b/tools/testing/kunit/kunit_kernel.py
> @@ -359,6 +359,7 @@ class LinuxSourceTree:
>                         args = []
>                 if filter_glob:
>                         args.append('kunit.filter_glob='+filter_glob)
> +               args.append('kunit.enable=1')
>
>                 process = self._ops.start(args, build_dir)
>                 assert process.stdout is not None  # tell mypy it's set
> --
> 2.37.1.595.g718a3a8f04-goog
>
> --
> You received this message because you are subscribed to the Google Groups "KUnit Development" group.
> To unsubscribe from this group and stop receiving emails from it, send an email to kunit-dev+unsubscribe@googlegroups.com.
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[-- Attachment #2: S/MIME Cryptographic Signature --]
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Re: [PATCH v2 1/2] kunit: add kunit.enable to enable/disable KUnit test

[Joe Fradley]

On Tue, Aug 23, 2022 at 9:31 PM David Gow <davidgow@google.com> wrote:
>
> On Tue, Aug 23, 2022 at 10:25 PM 'Joe Fradley' via KUnit Development
> <kunit-dev@googlegroups.com> wrote:
> >
> > This patch adds the kunit.enable module parameter that will need to be
> > set to true in addition to KUNIT being enabled for KUnit tests to run.
> > The default value is true giving backwards compatibility. However, for
> > the production+testing use case the new config option
> > KUNIT_DEFAULT_ENABLED can be set to N requiring the tester to opt-in
> > by passing kunit.enable=1 to the kernel.
> >
> > Signed-off-by: Joe Fradley <joefradley@google.com>
> > ---
>
> Thanks very much. This looks good to me, and works on my machine.
>
> I've put a few comments/ideas below, but none of them feel necessary to me.

Thank you for the review. I need to do one follow up revision to base this
off of the appropriate `linux-kselftest/kunit` branch.

>
> Regardless, this is
> Reviewed-by: David Gow <davidgow@google.com>
>
> Cheers,
> -- David
>
> > Changes since v1:
> > - Created a function to get kunit enable state
> > - Check kunit enable state in kunit_run_all_tests() in executor.c
> > - Load test module even if KUnit is disabled but still don't execute
> >   tests
> > - Simplified kunit disable message and kunit.enable parameter
> >   description
> > - Flipped around logic of new config to be KUNIT_DEFAULT_ENABLED
> > - kunit_tool.py now passes kunit.enable=1 to kernel
> >
> >  .../admin-guide/kernel-parameters.txt         |  6 +++++
> >  include/kunit/test.h                          |  2 ++
> >  lib/kunit/Kconfig                             | 11 +++++++++
> >  lib/kunit/executor.c                          |  4 ++++
> >  lib/kunit/test.c                              | 24 +++++++++++++++++++
> >  tools/testing/kunit/kunit_kernel.py           |  1 +
> >  6 files changed, 48 insertions(+)
> >
> > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> > index adfda56b2691..7aa3abd7f1c5 100644
> > --- a/Documentation/admin-guide/kernel-parameters.txt
> > +++ b/Documentation/admin-guide/kernel-parameters.txt
> > @@ -2432,6 +2432,12 @@
> >                         0: force disabled
> >                         1: force enabled
> >
> > +       kunit.enable=   [KUNIT] Enable executing KUnit tests. Requires
> > +                       CONFIG_KUNIT to be set to be fully enabled. The
> > +                       default value can be overridden via
> > +                       KUNIT_DEFAULT_ENABLED.
> > +                       Default is 1 (enabled)
> > +
> >         kvm.ignore_msrs=[KVM] Ignore guest accesses to unhandled MSRs.
> >                         Default is 0 (don't ignore, but inject #GP)
> >
> > diff --git a/include/kunit/test.h b/include/kunit/test.h
> > index c958855681cc..ee6bf4ecbd89 100644
> > --- a/include/kunit/test.h
> > +++ b/include/kunit/test.h
> > @@ -228,6 +228,8 @@ static inline void kunit_set_failure(struct kunit *test)
> >         WRITE_ONCE(test->status, KUNIT_FAILURE);
> >  }
> >
> > +bool kunit_enabled(void);
> > +
>
> This probably isn't strictly necessary at this stage, given that it
> just checks one variable. That being said, I don't think it hurts (and
> personally, I quite like it), and find it more future-proof than
> exposing the variable more widely anyway.

It also addressed it being a static variable.

>
> >  void kunit_init_test(struct kunit *test, const char *name, char *log);
> >
> >  int kunit_run_tests(struct kunit_suite *suite);
> > diff --git a/lib/kunit/Kconfig b/lib/kunit/Kconfig
> > index 0b5dfb001bac..626719b95bad 100644
> > --- a/lib/kunit/Kconfig
> > +++ b/lib/kunit/Kconfig
> > @@ -59,4 +59,15 @@ config KUNIT_ALL_TESTS
> >
> >           If unsure, say N.
> >
> > +config KUNIT_DEFAULT_ENABLED
> > +       bool "Default value of kunit.enable"
> > +       default y
> > +       help
> > +         Sets the default value of kunit.enable. If set to N then KUnit
> > +         tests will not execute unless kunit.enable=1 is passed to the
> > +         kernel command line.
> > +
> > +         In most cases this should be left as Y. Only if additional opt-in
> > +         behavior is needed should this be set to N.
> > +
> >  endif # KUNIT
> > diff --git a/lib/kunit/executor.c b/lib/kunit/executor.c
> > index 5e223327196a..9bbc422c284b 100644
> > --- a/lib/kunit/executor.c
> > +++ b/lib/kunit/executor.c
> > @@ -190,6 +190,10 @@ int kunit_run_all_tests(void)
> >  {
> >         struct suite_set suite_set = {__kunit_suites_start, __kunit_suites_end};
> >         int err = 0;
> > +       if (!kunit_enabled()) {
> > +               pr_info("kunit: disabled\n");
> > +               goto out;
> > +       }
> >
> >         if (filter_glob_param) {
> >                 suite_set = kunit_filter_suites(&suite_set, filter_glob_param, &err);
> > diff --git a/lib/kunit/test.c b/lib/kunit/test.c
> > index b73d5bb5c473..1e54373309a4 100644
> > --- a/lib/kunit/test.c
> > +++ b/lib/kunit/test.c
> > @@ -54,6 +54,17 @@ void __kunit_fail_current_test(const char *file, int line, const char *fmt, ...)
> >  EXPORT_SYMBOL_GPL(__kunit_fail_current_test);
> >  #endif
> >
> > +/*
> > + * Enable KUnit tests to run.
> > + */
> > +#ifdef CONFIG_KUNIT_DEFAULT_ENABLED
> > +static bool enable_param = true;
> > +#else
> > +static bool enable_param;
> > +#endif
> > +module_param_named(enable, enable_param, bool, 0);
> > +MODULE_PARM_DESC(enable, "Enable KUnit tests");
> > +
> >  /*
> >   * KUnit statistic mode:
> >   * 0 - disabled
> > @@ -586,10 +597,20 @@ static void kunit_init_suite(struct kunit_suite *suite)
> >         suite->suite_init_err = 0;
> >  }
> >
> > +bool kunit_enabled(void)
> > +{
> > +       return enable_param;
> > +}
> > +
> >  int __kunit_test_suites_init(struct kunit_suite * const * const suites, int num_suites)
> >  {
> >         unsigned int i;
> >
> > +       if (!kunit_enabled() && num_suites > 0) {
> > +               pr_info("kunit: disabled\n");
>
> _Maybe_ this could be pr_info_once(), if you were worried about spam
> (if a whole bunch of test modules were loaded at once). That being
> said, I prefer it as-is, as I don't think there are a lot of cases
> where large number of kunit test modules are loaded on a system with
> KUnit disable. And I'm liable to forget that KUnit is disabled if a
> system has been running for a while (and maybe one test module was
> loaded a boot), and end up wondering why my test isn't running.

That's the same conclusion I came to after considering the one time
message used for the test taint message.

>
> So, I'm all for leaving this as-is, personally.
>
> > +               return 0;
> > +       }
> > +
> >         for (i = 0; i < num_suites; i++) {
> >                 kunit_init_suite(suites[i]);
> >                 kunit_run_tests(suites[i]);
> > @@ -607,6 +628,9 @@ void __kunit_test_suites_exit(struct kunit_suite **suites, int num_suites)
> >  {
> >         unsigned int i;
> >
> > +       if (!kunit_enabled())
> > +               return;
> > +
> >         for (i = 0; i < num_suites; i++)
> >                 kunit_exit_suite(suites[i]);
> >
> > diff --git a/tools/testing/kunit/kunit_kernel.py b/tools/testing/kunit/kunit_kernel.py
> > index f5c26ea89714..ef794da420d7 100644
> > --- a/tools/testing/kunit/kunit_kernel.py
> > +++ b/tools/testing/kunit/kunit_kernel.py
> > @@ -359,6 +359,7 @@ class LinuxSourceTree:
> >                         args = []
> >                 if filter_glob:
> >                         args.append('kunit.filter_glob='+filter_glob)
> > +               args.append('kunit.enable=1')
> >
> >                 process = self._ops.start(args, build_dir)
> >                 assert process.stdout is not None  # tell mypy it's set
> > --
> > 2.37.1.595.g718a3a8f04-goog
> >
> > --
> > You received this message because you are subscribed to the Google Groups "KUnit Development" group.
> > To unsubscribe from this group and stop receiving emails from it, send an email to kunit-dev+unsubscribe@googlegroups.com.
> > To view this discussion on the web visit https://groups.google.com/d/msgid/kunit-dev/20220823142456.3977086-2-joefradley%40google.com.

Re: [PATCH v2 1/2] kunit: add kunit.enable to enable/disable KUnit test

[David Gow]

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On Wed, Aug 24, 2022 at 1:04 PM Joe Fradley <joefradley@google.com> wrote:
>
> On Tue, Aug 23, 2022 at 9:31 PM David Gow <davidgow@google.com> wrote:
> >
> > On Tue, Aug 23, 2022 at 10:25 PM 'Joe Fradley' via KUnit Development
> > <kunit-dev@googlegroups.com> wrote:
> > >
> > > This patch adds the kunit.enable module parameter that will need to be
> > > set to true in addition to KUNIT being enabled for KUnit tests to run.
> > > The default value is true giving backwards compatibility. However, for
> > > the production+testing use case the new config option
> > > KUNIT_DEFAULT_ENABLED can be set to N requiring the tester to opt-in
> > > by passing kunit.enable=1 to the kernel.
> > >
> > > Signed-off-by: Joe Fradley <joefradley@google.com>
> > > ---
> >
> > Thanks very much. This looks good to me, and works on my machine.
> >
> > I've put a few comments/ideas below, but none of them feel necessary to me.
>
> Thank you for the review. I need to do one follow up revision to base this
> off of the appropriate `linux-kselftest/kunit` branch.
>

This already applies cleanly to linux-kselftest/kunit -- it should be
fine as-is.

(It also applies fine to kselftest/kunit-fixes, for what it's worth.)

Cheers,
-- David

> >
> > Regardless, this is
> > Reviewed-by: David Gow <davidgow@google.com>
> >
> > Cheers,
> > -- David
> >
> > > Changes since v1:
> > > - Created a function to get kunit enable state
> > > - Check kunit enable state in kunit_run_all_tests() in executor.c
> > > - Load test module even if KUnit is disabled but still don't execute
> > >   tests
> > > - Simplified kunit disable message and kunit.enable parameter
> > >   description
> > > - Flipped around logic of new config to be KUNIT_DEFAULT_ENABLED
> > > - kunit_tool.py now passes kunit.enable=1 to kernel
> > >
> > >  .../admin-guide/kernel-parameters.txt         |  6 +++++
> > >  include/kunit/test.h                          |  2 ++
> > >  lib/kunit/Kconfig                             | 11 +++++++++
> > >  lib/kunit/executor.c                          |  4 ++++
> > >  lib/kunit/test.c                              | 24 +++++++++++++++++++
> > >  tools/testing/kunit/kunit_kernel.py           |  1 +
> > >  6 files changed, 48 insertions(+)
> > >
> > > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> > > index adfda56b2691..7aa3abd7f1c5 100644
> > > --- a/Documentation/admin-guide/kernel-parameters.txt
> > > +++ b/Documentation/admin-guide/kernel-parameters.txt
> > > @@ -2432,6 +2432,12 @@
> > >                         0: force disabled
> > >                         1: force enabled
> > >
> > > +       kunit.enable=   [KUNIT] Enable executing KUnit tests. Requires
> > > +                       CONFIG_KUNIT to be set to be fully enabled. The
> > > +                       default value can be overridden via
> > > +                       KUNIT_DEFAULT_ENABLED.
> > > +                       Default is 1 (enabled)
> > > +
> > >         kvm.ignore_msrs=[KVM] Ignore guest accesses to unhandled MSRs.
> > >                         Default is 0 (don't ignore, but inject #GP)
> > >
> > > diff --git a/include/kunit/test.h b/include/kunit/test.h
> > > index c958855681cc..ee6bf4ecbd89 100644
> > > --- a/include/kunit/test.h
> > > +++ b/include/kunit/test.h
> > > @@ -228,6 +228,8 @@ static inline void kunit_set_failure(struct kunit *test)
> > >         WRITE_ONCE(test->status, KUNIT_FAILURE);
> > >  }
> > >
> > > +bool kunit_enabled(void);
> > > +
> >
> > This probably isn't strictly necessary at this stage, given that it
> > just checks one variable. That being said, I don't think it hurts (and
> > personally, I quite like it), and find it more future-proof than
> > exposing the variable more widely anyway.
>
> It also addressed it being a static variable.
>
> >
> > >  void kunit_init_test(struct kunit *test, const char *name, char *log);
> > >
> > >  int kunit_run_tests(struct kunit_suite *suite);
> > > diff --git a/lib/kunit/Kconfig b/lib/kunit/Kconfig
> > > index 0b5dfb001bac..626719b95bad 100644
> > > --- a/lib/kunit/Kconfig
> > > +++ b/lib/kunit/Kconfig
> > > @@ -59,4 +59,15 @@ config KUNIT_ALL_TESTS
> > >
> > >           If unsure, say N.
> > >
> > > +config KUNIT_DEFAULT_ENABLED
> > > +       bool "Default value of kunit.enable"
> > > +       default y
> > > +       help
> > > +         Sets the default value of kunit.enable. If set to N then KUnit
> > > +         tests will not execute unless kunit.enable=1 is passed to the
> > > +         kernel command line.
> > > +
> > > +         In most cases this should be left as Y. Only if additional opt-in
> > > +         behavior is needed should this be set to N.
> > > +
> > >  endif # KUNIT
> > > diff --git a/lib/kunit/executor.c b/lib/kunit/executor.c
> > > index 5e223327196a..9bbc422c284b 100644
> > > --- a/lib/kunit/executor.c
> > > +++ b/lib/kunit/executor.c
> > > @@ -190,6 +190,10 @@ int kunit_run_all_tests(void)
> > >  {
> > >         struct suite_set suite_set = {__kunit_suites_start, __kunit_suites_end};
> > >         int err = 0;
> > > +       if (!kunit_enabled()) {
> > > +               pr_info("kunit: disabled\n");
> > > +               goto out;
> > > +       }
> > >
> > >         if (filter_glob_param) {
> > >                 suite_set = kunit_filter_suites(&suite_set, filter_glob_param, &err);
> > > diff --git a/lib/kunit/test.c b/lib/kunit/test.c
> > > index b73d5bb5c473..1e54373309a4 100644
> > > --- a/lib/kunit/test.c
> > > +++ b/lib/kunit/test.c
> > > @@ -54,6 +54,17 @@ void __kunit_fail_current_test(const char *file, int line, const char *fmt, ...)
> > >  EXPORT_SYMBOL_GPL(__kunit_fail_current_test);
> > >  #endif
> > >
> > > +/*
> > > + * Enable KUnit tests to run.
> > > + */
> > > +#ifdef CONFIG_KUNIT_DEFAULT_ENABLED
> > > +static bool enable_param = true;
> > > +#else
> > > +static bool enable_param;
> > > +#endif
> > > +module_param_named(enable, enable_param, bool, 0);
> > > +MODULE_PARM_DESC(enable, "Enable KUnit tests");
> > > +
> > >  /*
> > >   * KUnit statistic mode:
> > >   * 0 - disabled
> > > @@ -586,10 +597,20 @@ static void kunit_init_suite(struct kunit_suite *suite)
> > >         suite->suite_init_err = 0;
> > >  }
> > >
> > > +bool kunit_enabled(void)
> > > +{
> > > +       return enable_param;
> > > +}
> > > +
> > >  int __kunit_test_suites_init(struct kunit_suite * const * const suites, int num_suites)
> > >  {
> > >         unsigned int i;
> > >
> > > +       if (!kunit_enabled() && num_suites > 0) {
> > > +               pr_info("kunit: disabled\n");
> >
> > _Maybe_ this could be pr_info_once(), if you were worried about spam
> > (if a whole bunch of test modules were loaded at once). That being
> > said, I prefer it as-is, as I don't think there are a lot of cases
> > where large number of kunit test modules are loaded on a system with
> > KUnit disable. And I'm liable to forget that KUnit is disabled if a
> > system has been running for a while (and maybe one test module was
> > loaded a boot), and end up wondering why my test isn't running.
>
> That's the same conclusion I came to after considering the one time
> message used for the test taint message.
>
> >
> > So, I'm all for leaving this as-is, personally.
> >
> > > +               return 0;
> > > +       }
> > > +
> > >         for (i = 0; i < num_suites; i++) {
> > >                 kunit_init_suite(suites[i]);
> > >                 kunit_run_tests(suites[i]);
> > > @@ -607,6 +628,9 @@ void __kunit_test_suites_exit(struct kunit_suite **suites, int num_suites)
> > >  {
> > >         unsigned int i;
> > >
> > > +       if (!kunit_enabled())
> > > +               return;
> > > +
> > >         for (i = 0; i < num_suites; i++)
> > >                 kunit_exit_suite(suites[i]);
> > >
> > > diff --git a/tools/testing/kunit/kunit_kernel.py b/tools/testing/kunit/kunit_kernel.py
> > > index f5c26ea89714..ef794da420d7 100644
> > > --- a/tools/testing/kunit/kunit_kernel.py
> > > +++ b/tools/testing/kunit/kunit_kernel.py
> > > @@ -359,6 +359,7 @@ class LinuxSourceTree:
> > >                         args = []
> > >                 if filter_glob:
> > >                         args.append('kunit.filter_glob='+filter_glob)
> > > +               args.append('kunit.enable=1')
> > >
> > >                 process = self._ops.start(args, build_dir)
> > >                 assert process.stdout is not None  # tell mypy it's set
> > > --
> > > 2.37.1.595.g718a3a8f04-goog
> > >
> > > --
> > > You received this message because you are subscribed to the Google Groups "KUnit Development" group.
> > > To unsubscribe from this group and stop receiving emails from it, send an email to kunit-dev+unsubscribe@googlegroups.com.
> > > To view this discussion on the web visit https://groups.google.com/d/msgid/kunit-dev/20220823142456.3977086-2-joefradley%40google.com.

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Re: [PATCH v2 1/2] kunit: add kunit.enable to enable/disable KUnit test

[Joe Fradley]

On Tue, Aug 23, 2022 at 11:33 PM David Gow <davidgow@google.com> wrote:
>
> On Wed, Aug 24, 2022 at 1:04 PM Joe Fradley <joefradley@google.com> wrote:
> >
> > On Tue, Aug 23, 2022 at 9:31 PM David Gow <davidgow@google.com> wrote:
> > >
> > > On Tue, Aug 23, 2022 at 10:25 PM 'Joe Fradley' via KUnit Development
> > > <kunit-dev@googlegroups.com> wrote:
> > > >
> > > > This patch adds the kunit.enable module parameter that will need to be
> > > > set to true in addition to KUNIT being enabled for KUnit tests to run.
> > > > The default value is true giving backwards compatibility. However, for
> > > > the production+testing use case the new config option
> > > > KUNIT_DEFAULT_ENABLED can be set to N requiring the tester to opt-in
> > > > by passing kunit.enable=1 to the kernel.
> > > >
> > > > Signed-off-by: Joe Fradley <joefradley@google.com>
> > > > ---
> > >
> > > Thanks very much. This looks good to me, and works on my machine.
> > >
> > > I've put a few comments/ideas below, but none of them feel necessary to me.
> >
> > Thank you for the review. I need to do one follow up revision to base this
> > off of the appropriate `linux-kselftest/kunit` branch.
> >
>
> This already applies cleanly to linux-kselftest/kunit -- it should be
> fine as-is.

Ok great, I'll leave as-is.


>
> (It also applies fine to kselftest/kunit-fixes, for what it's worth.)
>
> Cheers,
> -- David
>
> > >
> > > Regardless, this is
> > > Reviewed-by: David Gow <davidgow@google.com>
> > >
> > > Cheers,
> > > -- David
> > >
> > > > Changes since v1:
> > > > - Created a function to get kunit enable state
> > > > - Check kunit enable state in kunit_run_all_tests() in executor.c
> > > > - Load test module even if KUnit is disabled but still don't execute
> > > >   tests
> > > > - Simplified kunit disable message and kunit.enable parameter
> > > >   description
> > > > - Flipped around logic of new config to be KUNIT_DEFAULT_ENABLED
> > > > - kunit_tool.py now passes kunit.enable=1 to kernel
> > > >
> > > >  .../admin-guide/kernel-parameters.txt         |  6 +++++
> > > >  include/kunit/test.h                          |  2 ++
> > > >  lib/kunit/Kconfig                             | 11 +++++++++
> > > >  lib/kunit/executor.c                          |  4 ++++
> > > >  lib/kunit/test.c                              | 24 +++++++++++++++++++
> > > >  tools/testing/kunit/kunit_kernel.py           |  1 +
> > > >  6 files changed, 48 insertions(+)
> > > >
> > > > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> > > > index adfda56b2691..7aa3abd7f1c5 100644
> > > > --- a/Documentation/admin-guide/kernel-parameters.txt
> > > > +++ b/Documentation/admin-guide/kernel-parameters.txt
> > > > @@ -2432,6 +2432,12 @@
> > > >                         0: force disabled
> > > >                         1: force enabled
> > > >
> > > > +       kunit.enable=   [KUNIT] Enable executing KUnit tests. Requires
> > > > +                       CONFIG_KUNIT to be set to be fully enabled. The
> > > > +                       default value can be overridden via
> > > > +                       KUNIT_DEFAULT_ENABLED.
> > > > +                       Default is 1 (enabled)
> > > > +
> > > >         kvm.ignore_msrs=[KVM] Ignore guest accesses to unhandled MSRs.
> > > >                         Default is 0 (don't ignore, but inject #GP)
> > > >
> > > > diff --git a/include/kunit/test.h b/include/kunit/test.h
> > > > index c958855681cc..ee6bf4ecbd89 100644
> > > > --- a/include/kunit/test.h
> > > > +++ b/include/kunit/test.h
> > > > @@ -228,6 +228,8 @@ static inline void kunit_set_failure(struct kunit *test)
> > > >         WRITE_ONCE(test->status, KUNIT_FAILURE);
> > > >  }
> > > >
> > > > +bool kunit_enabled(void);
> > > > +
> > >
> > > This probably isn't strictly necessary at this stage, given that it
> > > just checks one variable. That being said, I don't think it hurts (and
> > > personally, I quite like it), and find it more future-proof than
> > > exposing the variable more widely anyway.
> >
> > It also addressed it being a static variable.
> >
> > >
> > > >  void kunit_init_test(struct kunit *test, const char *name, char *log);
> > > >
> > > >  int kunit_run_tests(struct kunit_suite *suite);
> > > > diff --git a/lib/kunit/Kconfig b/lib/kunit/Kconfig
> > > > index 0b5dfb001bac..626719b95bad 100644
> > > > --- a/lib/kunit/Kconfig
> > > > +++ b/lib/kunit/Kconfig
> > > > @@ -59,4 +59,15 @@ config KUNIT_ALL_TESTS
> > > >
> > > >           If unsure, say N.
> > > >
> > > > +config KUNIT_DEFAULT_ENABLED
> > > > +       bool "Default value of kunit.enable"
> > > > +       default y
> > > > +       help
> > > > +         Sets the default value of kunit.enable. If set to N then KUnit
> > > > +         tests will not execute unless kunit.enable=1 is passed to the
> > > > +         kernel command line.
> > > > +
> > > > +         In most cases this should be left as Y. Only if additional opt-in
> > > > +         behavior is needed should this be set to N.
> > > > +
> > > >  endif # KUNIT
> > > > diff --git a/lib/kunit/executor.c b/lib/kunit/executor.c
> > > > index 5e223327196a..9bbc422c284b 100644
> > > > --- a/lib/kunit/executor.c
> > > > +++ b/lib/kunit/executor.c
> > > > @@ -190,6 +190,10 @@ int kunit_run_all_tests(void)
> > > >  {
> > > >         struct suite_set suite_set = {__kunit_suites_start, __kunit_suites_end};
> > > >         int err = 0;
> > > > +       if (!kunit_enabled()) {
> > > > +               pr_info("kunit: disabled\n");
> > > > +               goto out;
> > > > +       }
> > > >
> > > >         if (filter_glob_param) {
> > > >                 suite_set = kunit_filter_suites(&suite_set, filter_glob_param, &err);
> > > > diff --git a/lib/kunit/test.c b/lib/kunit/test.c
> > > > index b73d5bb5c473..1e54373309a4 100644
> > > > --- a/lib/kunit/test.c
> > > > +++ b/lib/kunit/test.c
> > > > @@ -54,6 +54,17 @@ void __kunit_fail_current_test(const char *file, int line, const char *fmt, ...)
> > > >  EXPORT_SYMBOL_GPL(__kunit_fail_current_test);
> > > >  #endif
> > > >
> > > > +/*
> > > > + * Enable KUnit tests to run.
> > > > + */
> > > > +#ifdef CONFIG_KUNIT_DEFAULT_ENABLED
> > > > +static bool enable_param = true;
> > > > +#else
> > > > +static bool enable_param;
> > > > +#endif
> > > > +module_param_named(enable, enable_param, bool, 0);
> > > > +MODULE_PARM_DESC(enable, "Enable KUnit tests");
> > > > +
> > > >  /*
> > > >   * KUnit statistic mode:
> > > >   * 0 - disabled
> > > > @@ -586,10 +597,20 @@ static void kunit_init_suite(struct kunit_suite *suite)
> > > >         suite->suite_init_err = 0;
> > > >  }
> > > >
> > > > +bool kunit_enabled(void)
> > > > +{
> > > > +       return enable_param;
> > > > +}
> > > > +
> > > >  int __kunit_test_suites_init(struct kunit_suite * const * const suites, int num_suites)
> > > >  {
> > > >         unsigned int i;
> > > >
> > > > +       if (!kunit_enabled() && num_suites > 0) {
> > > > +               pr_info("kunit: disabled\n");
> > >
> > > _Maybe_ this could be pr_info_once(), if you were worried about spam
> > > (if a whole bunch of test modules were loaded at once). That being
> > > said, I prefer it as-is, as I don't think there are a lot of cases
> > > where large number of kunit test modules are loaded on a system with
> > > KUnit disable. And I'm liable to forget that KUnit is disabled if a
> > > system has been running for a while (and maybe one test module was
> > > loaded a boot), and end up wondering why my test isn't running.
> >
> > That's the same conclusion I came to after considering the one time
> > message used for the test taint message.
> >
> > >
> > > So, I'm all for leaving this as-is, personally.
> > >
> > > > +               return 0;
> > > > +       }
> > > > +
> > > >         for (i = 0; i < num_suites; i++) {
> > > >                 kunit_init_suite(suites[i]);
> > > >                 kunit_run_tests(suites[i]);
> > > > @@ -607,6 +628,9 @@ void __kunit_test_suites_exit(struct kunit_suite **suites, int num_suites)
> > > >  {
> > > >         unsigned int i;
> > > >
> > > > +       if (!kunit_enabled())
> > > > +               return;
> > > > +
> > > >         for (i = 0; i < num_suites; i++)
> > > >                 kunit_exit_suite(suites[i]);
> > > >
> > > > diff --git a/tools/testing/kunit/kunit_kernel.py b/tools/testing/kunit/kunit_kernel.py
> > > > index f5c26ea89714..ef794da420d7 100644
> > > > --- a/tools/testing/kunit/kunit_kernel.py
> > > > +++ b/tools/testing/kunit/kunit_kernel.py
> > > > @@ -359,6 +359,7 @@ class LinuxSourceTree:
> > > >                         args = []
> > > >                 if filter_glob:
> > > >                         args.append('kunit.filter_glob='+filter_glob)
> > > > +               args.append('kunit.enable=1')
> > > >
> > > >                 process = self._ops.start(args, build_dir)
> > > >                 assert process.stdout is not None  # tell mypy it's set
> > > > --
> > > > 2.37.1.595.g718a3a8f04-goog
> > > >
> > > > --
> > > > You received this message because you are subscribed to the Google Groups "KUnit Development" group.
> > > > To unsubscribe from this group and stop receiving emails from it, send an email to kunit-dev+unsubscribe@googlegroups.com.
> > > > To view this discussion on the web visit https://groups.google.com/d/msgid/kunit-dev/20220823142456.3977086-2-joefradley%40google.com.

[PATCH v2 2/2] kunit: no longer call module_info(test, "Y") for kunit modules

[Joe Fradley]

Because KUnit test execution is not a guarantee with the kunit.enable
parameter we want to be careful to only taint the kernel when actual
tests run. Calling module_info(test, "Y") for every KUnit module
automatically causes the kernel to be tainted upon module load. Therefore,
we're removing this call and relying on the KUnit framework to taint the
kernel or not.

Signed-off-by: Joe Fradley <joefradley@google.com>
Reviewed-by: David Gow <davidgow@google.com>
Reviewed-by: Brendan Higgins <brendanhiggins@google.com>
---
Changes since v1:
- Added David's and Brendan's Reviewed-by for tags.

 include/kunit/test.h | 1 -
 1 file changed, 1 deletion(-)

diff --git a/include/kunit/test.h b/include/kunit/test.h
index ee6bf4ecbd89..512089e5ce4e 100644
--- a/include/kunit/test.h
+++ b/include/kunit/test.h
@@ -253,7 +253,6 @@ static inline int kunit_run_all_tests(void)
 #endif /* IS_BUILTIN(CONFIG_KUNIT) */
 
 #define __kunit_test_suites(unique_array, ...)				       \
-	MODULE_INFO(test, "Y");						       \
 	static struct kunit_suite *unique_array[]			       \
 	__aligned(sizeof(struct kunit_suite *))				       \
 	__used __section(".kunit_test_suites") = { __VA_ARGS__ }
-- 
2.37.1.595.g718a3a8f04-goog

Re: [PATCH v2 0/2] kunit: add boot time parameter to enable KUnit

[Tales Aparecida]

Hi,


This series is
Tested-by: Tales Aparecida <tales.aparecida@gmail.com>

1. Tested using kunit_tool: running tests and showing output as expected.

2. Tested further by running QEMU through virtme-run with:
   $ ../virtme/virtme-run --show-command --kdir ../linux/.for-amd/ --mods=auto --kopt kunit.enable=1

2.a. "KUNIT_DEFAULT_ENABLED" works as expected when "kunit.enable" is omitted
2.b. kunit.enable=0 results in printing "kunit: disabled" on boot and on loading test modules, as expected
3.c. kunit.enable=1 runs tests on boot and allows them to run when loading test modules

3. Regarding taint
3.a. /proc/sys/kernel/tainted is 0 when kunit.enable=0 and does not change when trying to load test modules.
3.b. /proc/sys/kernel/tainted is 0 when kunit.enable=1 until the first test runs, then it becomes 262144 (2^18) as expected.


On other note, there's something I would like to delve into below.


On 23/08/2022 11:24, Joe Fradley wrote:
> v2:
>  - Added enable check in executor.c to prevent wrong error output from
>    kunit_tool.py when run against a KUnit disabled kernel
>  - kunit_tool.py now passes kunit.enable=1
>  - Flipped around logic of new config to KUNIT_DEFAULT_ENABLED
>  - Now load modules containing tests but not executing them
>  - Various message/description text clean up
> 
> There are some use cases where the kernel binary is desired to be the same
> for both production and testing. This poses a problem for users of KUnit
> as built-in tests will automatically run at startup and test modules
> can still be loaded leaving the kernel in an unsafe state. There is a
> "test" taint flag that gets set if a test runs but nothing to prevent
> the execution.

Do you have any info on whether these use cases would have something against writing tests for static functions using the documented approach of including the tests into the actual runtime code? 
https://docs.kernel.org/dev-tools/kunit/usage.html#testing-static-functions

Otherwise, would them agree to export the symbols that need to be tested?

I would really like to understand better what are these use cases :)

> 
> This patch adds the kunit.enable module parameter that will need to be
> set to true in addition to KUNIT being enabled for KUnit tests to run.
> The default value is true giving backwards compatibility. However, for
> the production+testing use case the new config option KUNIT_DEFAULT_ENABLED
> can be set to N requiring the tester to opt-in by passing kunit.enable=1 to
> the kernel.
> 
> Joe Fradley (2):
>   kunit: add kunit.enable to enable/disable KUnit test
>   kunit: no longer call module_info(test, "Y") for kunit modules
> 
>  .../admin-guide/kernel-parameters.txt         |  6 +++++
>  include/kunit/test.h                          |  3 ++-
>  lib/kunit/Kconfig                             | 11 +++++++++
>  lib/kunit/executor.c                          |  4 ++++
>  lib/kunit/test.c                              | 24 +++++++++++++++++++
>  tools/testing/kunit/kunit_kernel.py           |  1 +
>  6 files changed, 48 insertions(+), 1 deletion(-)
> 

Great work!

Kind regards,
Tales

Re: [PATCH v2 0/2] kunit: add boot time parameter to enable KUnit

[Joe Fradley]

On Sat, Sep 24, 2022 at 5:42 PM Tales Aparecida
<tales.aparecida@gmail.com> wrote:
>
> Hi,
>
>
> This series is
> Tested-by: Tales Aparecida <tales.aparecida@gmail.com>
>
> 1. Tested using kunit_tool: running tests and showing output as expected.
>
> 2. Tested further by running QEMU through virtme-run with:
>    $ ../virtme/virtme-run --show-command --kdir ../linux/.for-amd/ --mods=auto --kopt kunit.enable=1
>
> 2.a. "KUNIT_DEFAULT_ENABLED" works as expected when "kunit.enable" is omitted
> 2.b. kunit.enable=0 results in printing "kunit: disabled" on boot and on loading test modules, as expected
> 3.c. kunit.enable=1 runs tests on boot and allows them to run when loading test modules
>
> 3. Regarding taint
> 3.a. /proc/sys/kernel/tainted is 0 when kunit.enable=0 and does not change when trying to load test modules.
> 3.b. /proc/sys/kernel/tainted is 0 when kunit.enable=1 until the first test runs, then it becomes 262144 (2^18) as expected.

Tales, thank you for doing this testing.

>
>
> On other note, there's something I would like to delve into below.
>
>
> On 23/08/2022 11:24, Joe Fradley wrote:
> > v2:
> >  - Added enable check in executor.c to prevent wrong error output from
> >    kunit_tool.py when run against a KUnit disabled kernel
> >  - kunit_tool.py now passes kunit.enable=1
> >  - Flipped around logic of new config to KUNIT_DEFAULT_ENABLED
> >  - Now load modules containing tests but not executing them
> >  - Various message/description text clean up
> >
> > There are some use cases where the kernel binary is desired to be the same
> > for both production and testing. This poses a problem for users of KUnit
> > as built-in tests will automatically run at startup and test modules
> > can still be loaded leaving the kernel in an unsafe state. There is a
> > "test" taint flag that gets set if a test runs but nothing to prevent
> > the execution.
>
> Do you have any info on whether these use cases would have something against writing tests for static functions using the documented approach of including the tests into the actual runtime code?
> https://docs.kernel.org/dev-tools/kunit/usage.html#testing-static-functions
>
> Otherwise, would them agree to export the symbols that need to be tested?
>
> I would really like to understand better what are these use cases :)

I feel using the static functions as described in your link is a good
alternative to
modules with embedded KUnit tests. However, this is a different use case then
I refer to, which is the ability to have the framework embedded in the
kernel for
both production and test with the control of test execution gated on a kernel
command line parameter.

>
> >
> > This patch adds the kunit.enable module parameter that will need to be
> > set to true in addition to KUNIT being enabled for KUnit tests to run.
> > The default value is true giving backwards compatibility. However, for
> > the production+testing use case the new config option KUNIT_DEFAULT_ENABLED
> > can be set to N requiring the tester to opt-in by passing kunit.enable=1 to
> > the kernel.
> >
> > Joe Fradley (2):
> >   kunit: add kunit.enable to enable/disable KUnit test
> >   kunit: no longer call module_info(test, "Y") for kunit modules
> >
> >  .../admin-guide/kernel-parameters.txt         |  6 +++++
> >  include/kunit/test.h                          |  3 ++-
> >  lib/kunit/Kconfig                             | 11 +++++++++
> >  lib/kunit/executor.c                          |  4 ++++
> >  lib/kunit/test.c                              | 24 +++++++++++++++++++
> >  tools/testing/kunit/kunit_kernel.py           |  1 +
> >  6 files changed, 48 insertions(+), 1 deletion(-)
> >
>
> Great work!
>
> Kind regards,
> Tales

Re: [PATCH v2 0/2] kunit: add boot time parameter to enable KUnit

[Tales Aparecida]

On 28/09/2022 10:58, Joe Fradley wrote:
> On Sat, Sep 24, 2022 at 5:42 PM Tales Aparecida
> <tales.aparecida@gmail.com> wrote:
>>
>> Hi,
>>
>>
>> This series is
>> Tested-by: Tales Aparecida <tales.aparecida@gmail.com>
>>
>> 1. Tested using kunit_tool: running tests and showing output as expected.
>>
>> 2. Tested further by running QEMU through virtme-run with:
>>    $ ../virtme/virtme-run --show-command --kdir ../linux/.for-amd/ --mods=auto --kopt kunit.enable=1
>>
>> 2.a. "KUNIT_DEFAULT_ENABLED" works as expected when "kunit.enable" is omitted
>> 2.b. kunit.enable=0 results in printing "kunit: disabled" on boot and on loading test modules, as expected
>> 3.c. kunit.enable=1 runs tests on boot and allows them to run when loading test modules
>>
>> 3. Regarding taint
>> 3.a. /proc/sys/kernel/tainted is 0 when kunit.enable=0 and does not change when trying to load test modules.
>> 3.b. /proc/sys/kernel/tainted is 0 when kunit.enable=1 until the first test runs, then it becomes 262144 (2^18) as expected.
> 
> Tales, thank you for doing this testing.
> 
>>
>>
>> On other note, there's something I would like to delve into below.
>>
>>
>> On 23/08/2022 11:24, Joe Fradley wrote:
>>> v2:
>>>  - Added enable check in executor.c to prevent wrong error output from
>>>    kunit_tool.py when run against a KUnit disabled kernel
>>>  - kunit_tool.py now passes kunit.enable=1
>>>  - Flipped around logic of new config to KUNIT_DEFAULT_ENABLED
>>>  - Now load modules containing tests but not executing them
>>>  - Various message/description text clean up
>>>
>>> There are some use cases where the kernel binary is desired to be the same
>>> for both production and testing. This poses a problem for users of KUnit
>>> as built-in tests will automatically run at startup and test modules
>>> can still be loaded leaving the kernel in an unsafe state. There is a
>>> "test" taint flag that gets set if a test runs but nothing to prevent
>>> the execution.
>>
>> Do you have any info on whether these use cases would have something against writing tests for static functions using the documented approach of including the tests into the actual runtime code?
>> https://docs.kernel.org/dev-tools/kunit/usage.html#testing-static-functions
>>
>> Otherwise, would them agree to export the symbols that need to be tested?
>>
>> I would really like to understand better what are these use cases :)
> 
> I feel using the static functions as described in your link is a good
> alternative to
> modules with embedded KUnit tests. However, this is a different use case then
> I refer to, which is the ability to have the framework embedded in the
> kernel for
> both production and test with the control of test execution gated on a kernel
> command line parameter.
> 

I have another question regarding the compilation in this use case.

Does it have a strict requirement to minimize the kernel size?
That is, is there any requirement around built-in test modules
and/or a plan to load test modules on demand when booting with
kunit.enable=1?


I would also like to know whether the use case includes running
unit tests for AMDGPU or DRM, just so we can be aware of it when
writing more tests for static functions using the approach shown
in that link. 

>>
>>>
>>> This patch adds the kunit.enable module parameter that will need to be
>>> set to true in addition to KUNIT being enabled for KUnit tests to run.
>>> The default value is true giving backwards compatibility. However, for
>>> the production+testing use case the new config option KUNIT_DEFAULT_ENABLED
>>> can be set to N requiring the tester to opt-in by passing kunit.enable=1 to
>>> the kernel.
>>>
>>> Joe Fradley (2):
>>>   kunit: add kunit.enable to enable/disable KUnit test
>>>   kunit: no longer call module_info(test, "Y") for kunit modules
>>>
>>>  .../admin-guide/kernel-parameters.txt         |  6 +++++
>>>  include/kunit/test.h                          |  3 ++-
>>>  lib/kunit/Kconfig                             | 11 +++++++++
>>>  lib/kunit/executor.c                          |  4 ++++
>>>  lib/kunit/test.c                              | 24 +++++++++++++++++++
>>>  tools/testing/kunit/kunit_kernel.py           |  1 +
>>>  6 files changed, 48 insertions(+), 1 deletion(-)
>>>
>>
>> Great work!
>>
>> Kind regards,
>> Tales

Re: [PATCH v2 0/2] kunit: add boot time parameter to enable KUnit

[Joe Fradley]

On Wed, Sep 28, 2022 at 10:26 AM Tales Aparecida
<tales.aparecida@gmail.com> wrote:
>
> On 28/09/2022 10:58, Joe Fradley wrote:
> > On Sat, Sep 24, 2022 at 5:42 PM Tales Aparecida
> > <tales.aparecida@gmail.com> wrote:
> >>
> >> Hi,
> >>
> >>
> >> This series is
> >> Tested-by: Tales Aparecida <tales.aparecida@gmail.com>
> >>
> >> 1. Tested using kunit_tool: running tests and showing output as expected.
> >>
> >> 2. Tested further by running QEMU through virtme-run with:
> >>    $ ../virtme/virtme-run --show-command --kdir ../linux/.for-amd/ --mods=auto --kopt kunit.enable=1
> >>
> >> 2.a. "KUNIT_DEFAULT_ENABLED" works as expected when "kunit.enable" is omitted
> >> 2.b. kunit.enable=0 results in printing "kunit: disabled" on boot and on loading test modules, as expected
> >> 3.c. kunit.enable=1 runs tests on boot and allows them to run when loading test modules
> >>
> >> 3. Regarding taint
> >> 3.a. /proc/sys/kernel/tainted is 0 when kunit.enable=0 and does not change when trying to load test modules.
> >> 3.b. /proc/sys/kernel/tainted is 0 when kunit.enable=1 until the first test runs, then it becomes 262144 (2^18) as expected.
> >
> > Tales, thank you for doing this testing.
> >
> >>
> >>
> >> On other note, there's something I would like to delve into below.
> >>
> >>
> >> On 23/08/2022 11:24, Joe Fradley wrote:
> >>> v2:
> >>>  - Added enable check in executor.c to prevent wrong error output from
> >>>    kunit_tool.py when run against a KUnit disabled kernel
> >>>  - kunit_tool.py now passes kunit.enable=1
> >>>  - Flipped around logic of new config to KUNIT_DEFAULT_ENABLED
> >>>  - Now load modules containing tests but not executing them
> >>>  - Various message/description text clean up
> >>>
> >>> There are some use cases where the kernel binary is desired to be the same
> >>> for both production and testing. This poses a problem for users of KUnit
> >>> as built-in tests will automatically run at startup and test modules
> >>> can still be loaded leaving the kernel in an unsafe state. There is a
> >>> "test" taint flag that gets set if a test runs but nothing to prevent
> >>> the execution.
> >>
> >> Do you have any info on whether these use cases would have something against writing tests for static functions using the documented approach of including the tests into the actual runtime code?
> >> https://docs.kernel.org/dev-tools/kunit/usage.html#testing-static-functions
> >>
> >> Otherwise, would them agree to export the symbols that need to be tested?
> >>
> >> I would really like to understand better what are these use cases :)
> >
> > I feel using the static functions as described in your link is a good
> > alternative to
> > modules with embedded KUnit tests. However, this is a different use case then
> > I refer to, which is the ability to have the framework embedded in the
> > kernel for
> > both production and test with the control of test execution gated on a kernel
> > command line parameter.
> >
>
> I have another question regarding the compilation in this use case.
>
> Does it have a strict requirement to minimize the kernel size?

Even though kunit.enable will work as expected for built-in tests,
it's geared more towards the loading test modules scenario. It doesn't
have any requirements for kernel size.  But if built-in tests are
included the cost of the extra space will need to be weighed against
the value of having the option to activate the tests via kunit.enable.

> That is, is there any requirement around built-in test modules
> and/or a plan to load test modules on demand when booting with
> kunit.enable=1?

There's no current plan to load test modules on demand that wouldn't
otherwise be loaded when kunit.enable=1.

>
>
> I would also like to know whether the use case includes running
> unit tests for AMDGPU or DRM, just so we can be aware of it when
> writing more tests for static functions using the approach shown
> in that link.

I can't speak specifically about AMDGPU or DRM at the moment
because it depends on the targets we're testing. But it's a good
question in general about tests that are embedded in modules. It's
effectively the same tradeoff I mentioned earlier in regards to built-in
tests. The pros in having the tests activated by kunit.enable would
need to outweigh the cons of the size addition. It would be
preferable for the tests to be in a separate module.



>
> >>
> >>>
> >>> This patch adds the kunit.enable module parameter that will need to be
> >>> set to true in addition to KUNIT being enabled for KUnit tests to run.
> >>> The default value is true giving backwards compatibility. However, for
> >>> the production+testing use case the new config option KUNIT_DEFAULT_ENABLED
> >>> can be set to N requiring the tester to opt-in by passing kunit.enable=1 to
> >>> the kernel.
> >>>
> >>> Joe Fradley (2):
> >>>   kunit: add kunit.enable to enable/disable KUnit test
> >>>   kunit: no longer call module_info(test, "Y") for kunit modules
> >>>
> >>>  .../admin-guide/kernel-parameters.txt         |  6 +++++
> >>>  include/kunit/test.h                          |  3 ++-
> >>>  lib/kunit/Kconfig                             | 11 +++++++++
> >>>  lib/kunit/executor.c                          |  4 ++++
> >>>  lib/kunit/test.c                              | 24 +++++++++++++++++++
> >>>  tools/testing/kunit/kunit_kernel.py           |  1 +
> >>>  6 files changed, 48 insertions(+), 1 deletion(-)
> >>>
> >>
> >> Great work!
> >>
> >> Kind regards,
> >> Tales