The DECLARE_IF_KUNIT macro will introduces identifiers only if CONFIG_KUNIT is enabled. Otherwise if CONFIG_KUNIT is not enabled no identifiers from the param list will be defined.

Signed-off-by: Michal Wajdeczko michal.wajdeczko@intel.com Reviewed-by: Rae Moar rmoar@google.com Reviewed-by: David Gow davidgow@google.com --- Cc: Lucas De Marchi lucas.demarchi@intel.com --- v2: include struct example in macro comment (Lucas) reformat kernel-doc for better output (Michal) --- include/kunit/visibility.h | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+)

diff --git a/include/kunit/visibility.h b/include/kunit/visibility.h index 0dfe35feeec6..c1825381adfc 100644 --- a/include/kunit/visibility.h +++ b/include/kunit/visibility.h @@ -11,6 +11,25 @@ #define _KUNIT_VISIBILITY_H

#if IS_ENABLED(CONFIG_KUNIT) + /** + * DECLARE_IF_KUNIT - Conditionally introduce identifiers + * @body: identifiers to be introduced conditionally + * + * This macro introduces identifiers only if CONFIG_KUNIT is enabled. + * Otherwise if CONFIG_KUNIT is not enabled no identifiers will be defined. + * + * .. code-block:: C + * + * struct example { + * // @foo: regular data + * int foo; + * + * // private: data available only for CONFIG_KUNIT + * DECLARE_IF_KUNIT(int bar); + * }; + */ + #define DECLARE_IF_KUNIT(body...) body + /** * VISIBLE_IF_KUNIT - A macro that sets symbols to be static if * CONFIG_KUNIT is not enabled. Otherwise if CONFIG_KUNIT is enabled @@ -26,6 +45,7 @@ #define EXPORT_SYMBOL_IF_KUNIT(symbol) EXPORT_SYMBOL_NS(symbol, \ EXPORTED_FOR_KUNIT_TESTING) #else + #define DECLARE_IF_KUNIT(body...) #define VISIBLE_IF_KUNIT static #define EXPORT_SYMBOL_IF_KUNIT(symbol) #endif

Currently, the 'static stub' API only allows function redirection for calls made from the kthread of the current test, which prevents the use of this functionality when the tested code is also used by other threads, outside of the KUnit test, like from the workqueue.

Add another set of macros to allow redirection to the replacement functions, which, unlike the KUNIT_STATIC_STUB_REDIRECT, will affect all calls done during the test execution.

These new stubs, named 'global', must be declared using dedicated KUNIT_DECLARE_GLOBAL_STUB() macro and then can be placed either as global static variables or as part of the other structures.

To properly maintain stubs lifecycle, they can be activated only from the main KUnit context. Some precaution is taken to avoid changing or deactivating replacement functions if one is still used by other thread.

Signed-off-by: Michal Wajdeczko michal.wajdeczko@intel.com --- Cc: Rae Moar rmoar@google.com Cc: David Gow davidgow@google.com Cc: Daniel Latypov dlatypov@google.com Cc: Lucas De Marchi lucas.demarchi@intel.com --- v2: s/FIXED_STUB/GLOBAL_STUB (David, Lucas) make it little more thread safe (Rae, David) wait until stub call finishes before test end (David) wait until stub call finishes before changing stub (David) allow stub deactivation (Rae) prefer kunit log (David) v3: fix s/fixed/global in comments (Lucas) improve sanitize (Lucas, Michal) --- include/kunit/static_stub.h | 158 ++++++++++++++++++++++++++++++++++++ lib/kunit/static_stub.c | 50 ++++++++++++ 2 files changed, 208 insertions(+)

diff --git a/include/kunit/static_stub.h b/include/kunit/static_stub.h index bf940322dfc0..350731eda523 100644 --- a/include/kunit/static_stub.h +++ b/include/kunit/static_stub.h @@ -12,12 +12,15 @@

/* If CONFIG_KUNIT is not enabled, these stubs quietly disappear. */ #define KUNIT_STATIC_STUB_REDIRECT(real_fn_name, args...) do {} while (0) +#define KUNIT_GLOBAL_STUB_REDIRECT(stub_name, args...) do {} while (0) +#define KUNIT_DECLARE_GLOBAL_STUB(stub_name, stub_type)

#else

#include <kunit/test.h> #include <kunit/test-bug.h>

+#include <linux/cleanup.h> /* for CLASS */ #include <linux/compiler.h> /* for {un,}likely() */ #include <linux/sched.h> /* for task_struct */

@@ -109,5 +112,160 @@ void __kunit_activate_static_stub(struct kunit *test, */ void kunit_deactivate_static_stub(struct kunit *test, void *real_fn_addr);

+/** + * struct kunit_global_stub - Represents a context of global function stub. + * @replacement: The address of replacement function. + * @owner: The KUnit test that owns the stub, valid only when @busy > 0. + * @busy: The stub busyness counter incremented on entry to the replacement + * function, decremented on exit, used to signal if the stub is idle. + * @idle: The completion state to indicate when the stub is idle again. + * + * This structure is for KUnit internal use only. + * See KUNIT_DECLARE_GLOBAL_STUB(). + */ +struct kunit_global_stub { + void *replacement; + struct kunit *owner; + atomic_t busy; + struct completion idle; +}; + +/** + * KUNIT_DECLARE_GLOBAL_STUB() - Declare a global function stub. + * @stub_name: The name of the stub, must be a valid identifier + * @stub_type: The type of the function that this stub will replace + * + * This macro will declare new identifier of an anonymous type that will + * represent global stub function that could be used by KUnit. It can be stored + * outside of the KUnit code. If the CONFIG_KUNIT is not enabled this will + * be evaluated to an empty statement. + * + * The anonymous type introduced by this macro is mostly a wrapper to generic + * struct kunit_global_stub but with additional dummy member, that is never + * used directly, but is needed to maintain the type of the stub function. + */ +#define KUNIT_DECLARE_GLOBAL_STUB(stub_name, stub_type) \ +union { \ + struct kunit_global_stub base; \ + typeof(stub_type) dummy; \ +} stub_name + +/* Internal struct to define guard class */ +struct kunit_global_stub_guard { + struct kunit_global_stub *stub; + void *active_replacement; +}; + +/* Internal class used to guard stub calls */ +DEFINE_CLASS(kunit_global_stub_guard, + struct kunit_global_stub_guard, + ({ + struct kunit_global_stub *stub = _T.stub; + bool active = !!_T.active_replacement; + + if (active && !atomic_dec_return(&stub->busy)) + complete_all(&stub->idle); + }), + ({ + class_kunit_global_stub_guard_t guard; + bool active = !!atomic_inc_not_zero(&stub->busy); + + guard.stub = stub; + guard.active_replacement = active ? READ_ONCE(stub->replacement) : NULL; + + guard; + }), + struct kunit_global_stub *stub) + +/** + * KUNIT_GLOBAL_STUB_REDIRECT() - Call a global function stub if activated. + * @stub: The function stub declared using KUNIT_DECLARE_GLOBAL_STUB() + * @args: All of the arguments passed to this stub + * + * This is a function prologue which is used to allow calls to the current + * function to be redirected if a KUnit is running. If the KUnit is not + * running or stub is not yet activated the function will continue execution + * as normal. + * + * The function stub must be declared with KUNIT_DECLARE_GLOBAL_STUB() that is + * stored in a place that is accessible from both the test code, which will + * activate this stub using kunit_activate_global_stub(), and from the function, + * where we will do this redirection using KUNIT_GLOBAL_STUB_REDIRECT(). + * + * Unlike the KUNIT_STATIC_STUB_REDIRECT(), this redirection will work + * even if the caller is not in a KUnit context (like a worker thread). + * + * Example: + * + * .. code-block:: c + * + * KUNIT_DECLARE_GLOBAL_STUB(func_stub, int (*)(int n)); + * + * int real_func(int n) + * { + * KUNIT_GLOBAL_STUB_REDIRECT(func_stub, n); + * return n + 1; + * } + * + * int replacement_func(int n) + * { + * return n + 100; + * } + * + * void example_test(struct kunit *test) + * { + * KUNIT_EXPECT_EQ(test, real_func(1), 2); + * kunit_activate_global_stub(test, func_stub, replacement_func); + * KUNIT_EXPECT_EQ(test, real_func(1), 101); + * } + */ +#define KUNIT_GLOBAL_STUB_REDIRECT(stub, args...) do { \ + if (kunit_is_running()) { \ + typeof(stub) *__stub = &(stub); \ + CLASS(kunit_global_stub_guard, guard)(&__stub->base); \ + typeof(__stub->dummy) replacement = guard.active_replacement; \ + if (unlikely(replacement)) { \ + kunit_info(__stub->base.owner, "%s: redirecting to %ps\n", \ + __func__, replacement); \ + return replacement(args); \ + } \ + } \ +} while (0) + +void __kunit_activate_global_stub(struct kunit *test, struct kunit_global_stub *stub, + void *replacement_addr); + +/** + * kunit_activate_global_stub() - Setup a global function stub. + * @test: Test case that wants to activate a global function stub + * @stub: The location of the function stub pointer + * @replacement: The replacement function + * + * This helper setups a function stub with the replacement function. + * It will also automatically deactivate the stub at the test end. + * + * The redirection can be disabled with kunit_deactivate_global_stub(). + * The stub must be declared using KUNIT_DECLARE_GLOBAL_STUB(). + */ +#define kunit_activate_global_stub(test, stub, replacement) do { \ + typeof(stub) *__stub = &(stub); \ + typecheck_fn(typeof(__stub->dummy), (replacement)); \ + __kunit_activate_global_stub((test), &__stub->base, (replacement)); \ +} while (0) + +void __kunit_deactivate_global_stub(struct kunit *test, struct kunit_global_stub *stub); + +/** + * kunit_deactivate_global_stub() - Disable a global function stub. + * @test: Test case that wants to deactivate a global function stub + * @stub: The location of the function stub pointer + * + * The stub must be declared using KUNIT_DECLARE_GLOBAL_STUB(). + */ +#define kunit_deactivate_global_stub(test, stub) do { \ + typeof(stub) *__stub = &(stub); \ + __kunit_deactivate_global_stub((test), &__stub->base); \ +} while (0) + #endif #endif diff --git a/lib/kunit/static_stub.c b/lib/kunit/static_stub.c index 92b2cccd5e76..c7000c8dbabe 100644 --- a/lib/kunit/static_stub.c +++ b/lib/kunit/static_stub.c @@ -121,3 +121,53 @@ void __kunit_activate_static_stub(struct kunit *test, } } EXPORT_SYMBOL_GPL(__kunit_activate_static_stub); + +static void sanitize_global_stub(void *data) +{ + struct kunit *test = kunit_get_current_test(); + struct kunit_global_stub *stub = data; + + KUNIT_EXPECT_NE(test, 0, atomic_read(&stub->busy)); + KUNIT_EXPECT_PTR_EQ(test, test, READ_ONCE(stub->owner)); + + reinit_completion(&stub->idle); + if (!atomic_dec_and_test(&stub->busy)) { + kunit_info(test, "waiting for %ps\n", stub->replacement); + KUNIT_EXPECT_EQ(test, 0, wait_for_completion_interruptible(&stub->idle)); + } + + WRITE_ONCE(stub->owner, NULL); + WRITE_ONCE(stub->replacement, NULL); +} + +/* + * Helper function for kunit_activate_global_stub(). The macro does + * typechecking, so use it instead. + */ +void __kunit_activate_global_stub(struct kunit *test, + struct kunit_global_stub *stub, + void *replacement_addr) +{ + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, stub); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, replacement_addr); + + kunit_release_action(test, sanitize_global_stub, stub); + KUNIT_EXPECT_EQ(test, 0, atomic_read(&stub->busy)); + + init_completion(&stub->idle); + WRITE_ONCE(stub->owner, test); + WRITE_ONCE(stub->replacement, replacement_addr); + + KUNIT_ASSERT_EQ(test, 1, atomic_inc_return(&stub->busy)); + KUNIT_ASSERT_EQ(test, 0, kunit_add_action_or_reset(test, sanitize_global_stub, stub)); +} +EXPORT_SYMBOL_GPL(__kunit_activate_global_stub); + +/* + * Helper function for kunit_deactivate_global_stub(). Use it instead. + */ +void __kunit_deactivate_global_stub(struct kunit *test, struct kunit_global_stub *stub) +{ + kunit_release_action(test, sanitize_global_stub, stub); +} +EXPORT_SYMBOL_GPL(__kunit_deactivate_global_stub);

While we already have few ASSERT() within the implementation, it's always better to have dedicated test cases. Add tests for: - automatic deactivation of the stubs at the test end - blocked deactivation until all active stub calls finish - blocked stub change until all active stub calls finish - safe abuse (deactivation without activation)

Signed-off-by: Michal Wajdeczko michal.wajdeczko@intel.com --- Cc: Rae Moar rmoar@google.com Cc: David Gow davidgow@google.com Cc: Lucas De Marchi lucas.demarchi@intel.com --- lib/kunit/kunit-test.c | 254 ++++++++++++++++++++++++++++++++++++++++- 1 file changed, 253 insertions(+), 1 deletion(-)

diff --git a/lib/kunit/kunit-test.c b/lib/kunit/kunit-test.c index 37e02be1e710..eb1bb312ad71 100644 --- a/lib/kunit/kunit-test.c +++ b/lib/kunit/kunit-test.c @@ -6,8 +6,10 @@ * Author: Brendan Higgins brendanhiggins@google.com */ #include "linux/gfp_types.h" +#include <kunit/static_stub.h> #include <kunit/test.h> #include <kunit/test-bug.h> +#include <kunit/visibility.h>

#include <linux/device.h> #include <kunit/device.h> @@ -866,10 +868,260 @@ static struct kunit_suite kunit_current_test_suite = { .test_cases = kunit_current_test_cases, };

+static struct { + /* this stub matches the real function */ + KUNIT_DECLARE_GLOBAL_STUB(first_stub, int (*)(int i)); + /* this stub matches only return type of the real function */ + KUNIT_DECLARE_GLOBAL_STUB(second_stub, int (*)(int bit, int data)); + /* this is an example stub that returns void */ + KUNIT_DECLARE_GLOBAL_STUB(void_stub, void (*)(void)); + /* this is an example how to store additional data for use by stubs */ + DECLARE_IF_KUNIT(int data); + DECLARE_IF_KUNIT(int counter); +} stubs = { + DECLARE_IF_KUNIT(.data = 3), +}; + +static int real_func(int i) +{ + KUNIT_GLOBAL_STUB_REDIRECT(stubs.first_stub, i); + KUNIT_GLOBAL_STUB_REDIRECT(stubs.second_stub, BIT(i), stubs.data); + + return i; +} + +struct real_work { + struct work_struct work; + int param; + int result; +}; + +static void real_work_func(struct work_struct *work) +{ + struct real_work *w = container_of(work, typeof(*w), work); + + w->result = real_func(w->param); +} + +static int real_func_async(int i) +{ + struct real_work w = { .param = i, .result = -EINPROGRESS }; + + INIT_WORK_ONSTACK(&w.work, real_work_func); + schedule_work(&w.work); + flush_work(&w.work); + destroy_work_on_stack(&w.work); + + return w.result; +} + +static int replacement_func(int i) +{ + return i + 1; +} + +static int other_replacement_func(int i) +{ + return i + 10; +} + +static int super_replacement_func(int bit, int data) +{ + return bit * data; +} + +static int slow_replacement_func(int i) +{ + schedule_timeout_interruptible(HZ / 20); + return replacement_func(i); +} + +static void real_void_func(void) +{ + KUNIT_GLOBAL_STUB_REDIRECT(stubs.void_stub); + DECLARE_IF_KUNIT(stubs.counter++); +} + +static void replacement_void_func(void) +{ + stubs.counter--; +} + +static void expect_deactivated(void *data) +{ + struct kunit *test = kunit_get_current_test(); + + KUNIT_EXPECT_NULL(test, stubs.first_stub.base.owner); + KUNIT_EXPECT_NULL(test, stubs.first_stub.base.replacement); + KUNIT_EXPECT_NULL(test, stubs.second_stub.base.owner); + KUNIT_EXPECT_NULL(test, stubs.second_stub.base.replacement); + KUNIT_EXPECT_NULL(test, stubs.void_stub.base.owner); + KUNIT_EXPECT_NULL(test, stubs.void_stub.base.replacement); +} + +static void kunit_global_stub_test_deactivate(struct kunit *test) +{ + /* make sure everything will be deactivated */ + KUNIT_ASSERT_EQ(test, 0, kunit_add_action_or_reset(test, expect_deactivated, test)); + + /* deactivate without activate */ + kunit_deactivate_global_stub(test, stubs.first_stub); + + /* deactivate twice */ + kunit_deactivate_global_stub(test, stubs.first_stub); + + /* allow to skip deactivation (will be tested by expect_deactivated action) */ + kunit_activate_global_stub(test, stubs.first_stub, replacement_func); +} + +static void kunit_global_stub_test_activate(struct kunit *test) +{ + int real, replacement, other, super, i = 2; + + /* prerequisites */ + real_void_func(); + KUNIT_ASSERT_EQ(test, stubs.counter, 1); + replacement_void_func(); + KUNIT_ASSERT_EQ(test, stubs.counter, 0); + + /* prerequisites cont'd */ + KUNIT_ASSERT_EQ(test, real_func(i), real = real_func_async(i)); + KUNIT_ASSERT_NE(test, real_func(i), replacement = replacement_func(i)); + KUNIT_ASSERT_NE(test, real_func(i), other = other_replacement_func(i)); + KUNIT_ASSERT_NE(test, real_func(i), super = super_replacement_func(BIT(i), stubs.data)); + + /* make sure everything will be deactivated */ + KUNIT_ASSERT_EQ(test, 0, kunit_add_action_or_reset(test, expect_deactivated, test)); + + /* allow to activate replacement */ + kunit_activate_global_stub(test, stubs.void_stub, replacement_void_func); + real_void_func(); + KUNIT_ASSERT_EQ(test, stubs.counter, -1); + + /* allow to activate replacement */ + kunit_activate_global_stub(test, stubs.first_stub, replacement_func); + KUNIT_EXPECT_EQ(test, real_func(i), replacement); + KUNIT_EXPECT_EQ(test, real_func_async(i), replacement); + + /* allow to change replacement */ + kunit_activate_global_stub(test, stubs.first_stub, other_replacement_func); + KUNIT_EXPECT_EQ(test, real_func(i), other); + KUNIT_EXPECT_EQ(test, real_func_async(i), other); + + /* allow to deactivate replacement */ + kunit_deactivate_global_stub(test, stubs.first_stub); + KUNIT_EXPECT_EQ(test, real_func(i), real); + KUNIT_EXPECT_EQ(test, real_func_async(i), real); + + /* allow to activate replacement with different arguments */ + kunit_activate_global_stub(test, stubs.second_stub, super_replacement_func); + KUNIT_EXPECT_EQ(test, real_func(i), super); + KUNIT_EXPECT_EQ(test, real_func_async(i), super); + + /* allow to deactivate twice */ + kunit_deactivate_global_stub(test, stubs.second_stub); + kunit_deactivate_global_stub(test, stubs.second_stub); + KUNIT_EXPECT_EQ(test, real_func_async(i), real); + KUNIT_EXPECT_EQ(test, real_func(i), real); +} + +static void flush_real_work(void *data) +{ + struct real_work *w = data; + + flush_work(&w->work); +} + +static void __kunit_global_stub_test_slow(struct kunit *test, bool replace) +{ + int real, replacement, other, i = replace ? 3 : 5; + struct real_work *w; + + /* prerequisites */ + KUNIT_ASSERT_EQ(test, real_func(i), real = real_func_async(i)); + KUNIT_ASSERT_NE(test, real_func(i), replacement = slow_replacement_func(i)); + KUNIT_ASSERT_NE(test, real_func(i), other = other_replacement_func(i)); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, w = kunit_kzalloc(test, sizeof(*w), GFP_KERNEL)); + INIT_WORK(&w->work, real_work_func); + KUNIT_ASSERT_EQ(test, 0, kunit_add_action_or_reset(test, flush_real_work, w)); + KUNIT_ASSERT_EQ(test, 0, kunit_add_action_or_reset(test, expect_deactivated, test)); + + /* allow to activate replacement */ + kunit_activate_global_stub(test, stubs.first_stub, slow_replacement_func); + KUNIT_EXPECT_EQ(test, real_func_async(i), replacement); + + w->param = i; + w->result = 0; + queue_work(system_long_wq, &w->work); + + /* wait until work starts */ + while (work_pending(&w->work)) + schedule_timeout_interruptible(HZ / 100); + KUNIT_EXPECT_NE(test, work_busy(&w->work), 0); + + /* wait until work enters the stub */ + while (atomic_read(&stubs.first_stub.base.busy) < 2) + schedule_timeout_interruptible(HZ / 100); + + /* stub should be still busy(2) at this point */ + KUNIT_EXPECT_EQ(test, 2, atomic_read(&stubs.first_stub.base.busy)); + KUNIT_EXPECT_EQ(test, w->result, 0); + + if (replace) { + /* try replace the stub, it should be just activated(1) */ + kunit_activate_global_stub(test, stubs.first_stub, other_replacement_func); + KUNIT_EXPECT_EQ(test, 1, atomic_read(&stubs.first_stub.base.busy)); + } else { + /* try to deactivate the stub, it should be disabled(0) */ + kunit_deactivate_global_stub(test, stubs.first_stub); + KUNIT_EXPECT_EQ(test, 0, atomic_read(&stubs.first_stub.base.busy)); + } + + /* and results from the worker should be available */ + KUNIT_EXPECT_EQ(test, w->result, replacement); + KUNIT_EXPECT_NE(test, w->result, real); + KUNIT_EXPECT_NE(test, w->result, other); + + if (replace) + KUNIT_EXPECT_EQ(test, real_func_async(i), other); + else + KUNIT_EXPECT_EQ(test, real_func_async(i), real); +} + +static void kunit_global_stub_test_slow_deactivate(struct kunit *test) +{ + __kunit_global_stub_test_slow(test, false); +} + +static void kunit_global_stub_test_slow_replace(struct kunit *test) +{ + __kunit_global_stub_test_slow(test, true); +} + +static int kunit_global_stub_test_init(struct kunit *test) +{ + stubs.counter = 0; + return 0; +} + +static struct kunit_case kunit_global_stub_test_cases[] = { + KUNIT_CASE(kunit_global_stub_test_activate), + KUNIT_CASE(kunit_global_stub_test_deactivate), + KUNIT_CASE_SLOW(kunit_global_stub_test_slow_deactivate), + KUNIT_CASE_SLOW(kunit_global_stub_test_slow_replace), + {} +}; + +static struct kunit_suite kunit_global_stub_suite = { + .name = "kunit_global_stub", + .init = kunit_global_stub_test_init, + .test_cases = kunit_global_stub_test_cases, +}; + kunit_test_suites(&kunit_try_catch_test_suite, &kunit_resource_test_suite, &kunit_log_test_suite, &kunit_status_test_suite, &kunit_current_test_suite, &kunit_device_test_suite, - &kunit_fault_test_suite); + &kunit_fault_test_suite, &kunit_global_stub_suite);

MODULE_DESCRIPTION("KUnit test for core test infrastructure"); MODULE_LICENSE("GPL v2");