From ed6d74446cbfb88c747d4b32477a9d46132694db Mon Sep 17 00:00:00 2001 From: Andrey Konovalov Date: Thu, 24 Mar 2022 18:12:02 -0700 Subject: kasan: test: support async (again) and asymm modes for HW_TAGS Async mode support has already been implemented in commit e80a76aa1a91 ("kasan, arm64: tests supports for HW_TAGS async mode") but then got accidentally broken in commit 99734b535d9b ("kasan: detect false-positives in tests"). Restore the changes removed by the latter patch and adapt them for asymm mode: add a sync_fault flag to kunit_kasan_expectation that only get set if the MTE fault was synchronous, and reenable MTE on such faults in tests. Also rename kunit_kasan_expectation to kunit_kasan_status and move its definition to mm/kasan/kasan.h from include/linux/kasan.h, as this structure is only internally used by KASAN. Also put the structure definition under IS_ENABLED(CONFIG_KUNIT). Link: https://lkml.kernel.org/r/133970562ccacc93ba19d754012c562351d4a8c8.1645033139.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov Cc: Marco Elver Cc: Alexander Potapenko Cc: Dmitry Vyukov Cc: Andrey Ryabinin Cc: Vincenzo Frascino Cc: Catalin Marinas Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/kasan.h | 5 ----- lib/test_kasan.c | 39 ++++++++++++++++++++++----------------- mm/kasan/hw_tags.c | 18 +++++++++--------- mm/kasan/kasan.h | 14 ++++++++++++-- mm/kasan/report.c | 17 +++++++++-------- 5 files changed, 52 insertions(+), 41 deletions(-) diff --git a/include/linux/kasan.h b/include/linux/kasan.h index 903b9453931d..fe36215807f7 100644 --- a/include/linux/kasan.h +++ b/include/linux/kasan.h @@ -19,11 +19,6 @@ struct task_struct; #include #include -/* kasan_data struct is used in KUnit tests for KASAN expected failures */ -struct kunit_kasan_expectation { - bool report_found; -}; - #endif typedef unsigned int __bitwise kasan_vmalloc_flags_t; diff --git a/lib/test_kasan.c b/lib/test_kasan.c index 2addd0c66acf..72391f992689 100644 --- a/lib/test_kasan.c +++ b/lib/test_kasan.c @@ -37,7 +37,7 @@ void *kasan_ptr_result; int kasan_int_result; static struct kunit_resource resource; -static struct kunit_kasan_expectation fail_data; +static struct kunit_kasan_status test_status; static bool multishot; /* @@ -54,58 +54,63 @@ static int kasan_test_init(struct kunit *test) } multishot = kasan_save_enable_multi_shot(); - fail_data.report_found = false; + test_status.report_found = false; + test_status.sync_fault = false; kunit_add_named_resource(test, NULL, NULL, &resource, - "kasan_data", &fail_data); + "kasan_status", &test_status); return 0; } static void kasan_test_exit(struct kunit *test) { kasan_restore_multi_shot(multishot); - KUNIT_EXPECT_FALSE(test, fail_data.report_found); + KUNIT_EXPECT_FALSE(test, test_status.report_found); } /** * KUNIT_EXPECT_KASAN_FAIL() - check that the executed expression produces a * KASAN report; causes a test failure otherwise. This relies on a KUnit - * resource named "kasan_data". Do not use this name for KUnit resources + * resource named "kasan_status". Do not use this name for KUnit resources * outside of KASAN tests. * - * For hardware tag-based KASAN in sync mode, when a tag fault happens, tag + * For hardware tag-based KASAN, when a synchronous tag fault happens, tag * checking is auto-disabled. When this happens, this test handler reenables * tag checking. As tag checking can be only disabled or enabled per CPU, * this handler disables migration (preemption). * - * Since the compiler doesn't see that the expression can change the fail_data + * Since the compiler doesn't see that the expression can change the test_status * fields, it can reorder or optimize away the accesses to those fields. * Use READ/WRITE_ONCE() for the accesses and compiler barriers around the * expression to prevent that. * - * In between KUNIT_EXPECT_KASAN_FAIL checks, fail_data.report_found is kept as - * false. This allows detecting KASAN reports that happen outside of the checks - * by asserting !fail_data.report_found at the start of KUNIT_EXPECT_KASAN_FAIL - * and in kasan_test_exit. + * In between KUNIT_EXPECT_KASAN_FAIL checks, test_status.report_found is kept + * as false. This allows detecting KASAN reports that happen outside of the + * checks by asserting !test_status.report_found at the start of + * KUNIT_EXPECT_KASAN_FAIL and in kasan_test_exit. */ #define KUNIT_EXPECT_KASAN_FAIL(test, expression) do { \ if (IS_ENABLED(CONFIG_KASAN_HW_TAGS) && \ kasan_sync_fault_possible()) \ migrate_disable(); \ - KUNIT_EXPECT_FALSE(test, READ_ONCE(fail_data.report_found)); \ + KUNIT_EXPECT_FALSE(test, READ_ONCE(test_status.report_found)); \ barrier(); \ expression; \ barrier(); \ - if (!READ_ONCE(fail_data.report_found)) { \ + if (kasan_async_fault_possible()) \ + kasan_force_async_fault(); \ + if (!READ_ONCE(test_status.report_found)) { \ KUNIT_FAIL(test, KUNIT_SUBTEST_INDENT "KASAN failure " \ "expected in \"" #expression \ "\", but none occurred"); \ } \ - if (IS_ENABLED(CONFIG_KASAN_HW_TAGS)) { \ - if (READ_ONCE(fail_data.report_found)) \ - kasan_enable_tagging_sync(); \ + if (IS_ENABLED(CONFIG_KASAN_HW_TAGS) && \ + kasan_sync_fault_possible()) { \ + if (READ_ONCE(test_status.report_found) && \ + READ_ONCE(test_status.sync_fault)) \ + kasan_enable_tagging(); \ migrate_enable(); \ } \ - WRITE_ONCE(fail_data.report_found, false); \ + WRITE_ONCE(test_status.report_found, false); \ } while (0) #define KASAN_TEST_NEEDS_CONFIG_ON(test, config) do { \ diff --git a/mm/kasan/hw_tags.c b/mm/kasan/hw_tags.c index fad1887e54c0..07a76c46daa5 100644 --- a/mm/kasan/hw_tags.c +++ b/mm/kasan/hw_tags.c @@ -172,12 +172,7 @@ void kasan_init_hw_tags_cpu(void) * Enable async or asymm modes only when explicitly requested * through the command line. */ - if (kasan_arg_mode == KASAN_ARG_MODE_ASYNC) - hw_enable_tagging_async(); - else if (kasan_arg_mode == KASAN_ARG_MODE_ASYMM) - hw_enable_tagging_asymm(); - else - hw_enable_tagging_sync(); + kasan_enable_tagging(); } /* kasan_init_hw_tags() is called once on boot CPU. */ @@ -343,11 +338,16 @@ void __kasan_poison_vmalloc(const void *start, unsigned long size) #if IS_ENABLED(CONFIG_KASAN_KUNIT_TEST) -void kasan_enable_tagging_sync(void) +void kasan_enable_tagging(void) { - hw_enable_tagging_sync(); + if (kasan_arg_mode == KASAN_ARG_MODE_ASYNC) + hw_enable_tagging_async(); + else if (kasan_arg_mode == KASAN_ARG_MODE_ASYMM) + hw_enable_tagging_asymm(); + else + hw_enable_tagging_sync(); } -EXPORT_SYMBOL_GPL(kasan_enable_tagging_sync); +EXPORT_SYMBOL_GPL(kasan_enable_tagging); void kasan_force_async_fault(void) { diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h index 4d67408e8407..d1e111b7d5d8 100644 --- a/mm/kasan/kasan.h +++ b/mm/kasan/kasan.h @@ -7,6 +7,16 @@ #include #include +#if IS_ENABLED(CONFIG_KUNIT) + +/* Used in KUnit-compatible KASAN tests. */ +struct kunit_kasan_status { + bool report_found; + bool sync_fault; +}; + +#endif + #ifdef CONFIG_KASAN_HW_TAGS #include @@ -350,12 +360,12 @@ static inline const void *arch_kasan_set_tag(const void *addr, u8 tag) #if defined(CONFIG_KASAN_HW_TAGS) && IS_ENABLED(CONFIG_KASAN_KUNIT_TEST) -void kasan_enable_tagging_sync(void); +void kasan_enable_tagging(void); void kasan_force_async_fault(void); #else /* CONFIG_KASAN_HW_TAGS || CONFIG_KASAN_KUNIT_TEST */ -static inline void kasan_enable_tagging_sync(void) { } +static inline void kasan_enable_tagging(void) { } static inline void kasan_force_async_fault(void) { } #endif /* CONFIG_KASAN_HW_TAGS || CONFIG_KASAN_KUNIT_TEST */ diff --git a/mm/kasan/report.c b/mm/kasan/report.c index f14146563d41..137c2c0b09db 100644 --- a/mm/kasan/report.c +++ b/mm/kasan/report.c @@ -336,20 +336,21 @@ static bool report_enabled(void) } #if IS_ENABLED(CONFIG_KUNIT) -static void kasan_update_kunit_status(struct kunit *cur_test) +static void kasan_update_kunit_status(struct kunit *cur_test, bool sync) { struct kunit_resource *resource; - struct kunit_kasan_expectation *kasan_data; + struct kunit_kasan_status *status; - resource = kunit_find_named_resource(cur_test, "kasan_data"); + resource = kunit_find_named_resource(cur_test, "kasan_status"); if (!resource) { kunit_set_failure(cur_test); return; } - kasan_data = (struct kunit_kasan_expectation *)resource->data; - WRITE_ONCE(kasan_data->report_found, true); + status = (struct kunit_kasan_status *)resource->data; + WRITE_ONCE(status->report_found, true); + WRITE_ONCE(status->sync_fault, sync); kunit_put_resource(resource); } #endif /* IS_ENABLED(CONFIG_KUNIT) */ @@ -363,7 +364,7 @@ void kasan_report_invalid_free(void *object, unsigned long ip) #if IS_ENABLED(CONFIG_KUNIT) if (current->kunit_test) - kasan_update_kunit_status(current->kunit_test); + kasan_update_kunit_status(current->kunit_test, true); #endif /* IS_ENABLED(CONFIG_KUNIT) */ start_report(&flags); @@ -383,7 +384,7 @@ void kasan_report_async(void) #if IS_ENABLED(CONFIG_KUNIT) if (current->kunit_test) - kasan_update_kunit_status(current->kunit_test); + kasan_update_kunit_status(current->kunit_test, false); #endif /* IS_ENABLED(CONFIG_KUNIT) */ start_report(&flags); @@ -405,7 +406,7 @@ static void __kasan_report(unsigned long addr, size_t size, bool is_write, #if IS_ENABLED(CONFIG_KUNIT) if (current->kunit_test) - kasan_update_kunit_status(current->kunit_test); + kasan_update_kunit_status(current->kunit_test, true); #endif /* IS_ENABLED(CONFIG_KUNIT) */ disable_trace_on_warning(); -- cgit