From 7ce0ea19d50e4e97a8da69f616ffa8afbb532a93 Mon Sep 17 00:00:00 2001 From: Andrey Konovalov Date: Tue, 27 Sep 2022 19:09:09 +0200 Subject: kasan: switch kunit tests to console tracepoints Switch KUnit-compatible KASAN tests from using per-task KUnit resources to console tracepoints. This allows for two things: 1. Migrating tests that trigger a KASAN report in the context of a task other than current to KUnit framework. This is implemented in the patches that follow. 2. Parsing and matching the contents of KASAN reports. This is not yet implemented. Link: https://lkml.kernel.org/r/9345acdd11e953b207b0ed4724ff780e63afeb36.1664298455.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov Reviewed-by: Marco Elver Cc: Alexander Potapenko Cc: Andrey Ryabinin Cc: Dmitry Vyukov Signed-off-by: Andrew Morton --- mm/kasan/kasan.h | 8 ----- mm/kasan/kasan_test.c | 85 +++++++++++++++++++++++++++++++++++++-------------- mm/kasan/report.c | 31 ------------------- 3 files changed, 62 insertions(+), 62 deletions(-) (limited to 'mm/kasan') diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h index abbcc1b0eec5..a84491bc4867 100644 --- a/mm/kasan/kasan.h +++ b/mm/kasan/kasan.h @@ -261,14 +261,6 @@ struct kasan_stack_ring { #endif /* CONFIG_KASAN_SW_TAGS || CONFIG_KASAN_HW_TAGS */ -#if IS_ENABLED(CONFIG_KASAN_KUNIT_TEST) -/* Used in KUnit-compatible KASAN tests. */ -struct kunit_kasan_status { - bool report_found; - bool sync_fault; -}; -#endif - #if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS) static inline const void *kasan_shadow_to_mem(const void *shadow_addr) diff --git a/mm/kasan/kasan_test.c b/mm/kasan/kasan_test.c index 0d59098f0876..0ff20bfa3376 100644 --- a/mm/kasan/kasan_test.c +++ b/mm/kasan/kasan_test.c @@ -5,8 +5,12 @@ * Author: Andrey Ryabinin */ +#define pr_fmt(fmt) "kasan_test: " fmt + +#include #include #include +#include #include #include #include @@ -14,21 +18,28 @@ #include #include #include +#include #include #include +#include #include -#include #include -#include +#include #include -#include - #include "kasan.h" #define OOB_TAG_OFF (IS_ENABLED(CONFIG_KASAN_GENERIC) ? 0 : KASAN_GRANULE_SIZE) +static bool multishot; + +/* Fields set based on lines observed in the console. */ +static struct { + bool report_found; + bool async_fault; +} test_status; + /* * Some tests use these global variables to store return values from function * calls that could otherwise be eliminated by the compiler as dead code. @@ -36,35 +47,61 @@ void *kasan_ptr_result; int kasan_int_result; -static struct kunit_resource resource; -static struct kunit_kasan_status test_status; -static bool multishot; +/* Probe for console output: obtains test_status lines of interest. */ +static void probe_console(void *ignore, const char *buf, size_t len) +{ + if (strnstr(buf, "BUG: KASAN: ", len)) + WRITE_ONCE(test_status.report_found, true); + else if (strnstr(buf, "Asynchronous fault: ", len)) + WRITE_ONCE(test_status.async_fault, true); +} -/* - * Temporarily enable multi-shot mode. Otherwise, KASAN would only report the - * first detected bug and panic the kernel if panic_on_warn is enabled. For - * hardware tag-based KASAN also allow tag checking to be reenabled for each - * test, see the comment for KUNIT_EXPECT_KASAN_FAIL(). - */ -static int kasan_test_init(struct kunit *test) +static void register_tracepoints(struct tracepoint *tp, void *ignore) +{ + check_trace_callback_type_console(probe_console); + if (!strcmp(tp->name, "console")) + WARN_ON(tracepoint_probe_register(tp, probe_console, NULL)); +} + +static void unregister_tracepoints(struct tracepoint *tp, void *ignore) +{ + if (!strcmp(tp->name, "console")) + tracepoint_probe_unregister(tp, probe_console, NULL); +} + +static int kasan_suite_init(struct kunit_suite *suite) { if (!kasan_enabled()) { - kunit_err(test, "can't run KASAN tests with KASAN disabled"); + pr_err("Can't run KASAN tests with KASAN disabled"); return -1; } + /* + * Temporarily enable multi-shot mode. Otherwise, KASAN would only + * report the first detected bug and panic the kernel if panic_on_warn + * is enabled. + */ multishot = kasan_save_enable_multi_shot(); - test_status.report_found = false; - test_status.sync_fault = false; - kunit_add_named_resource(test, NULL, NULL, &resource, - "kasan_status", &test_status); + + /* + * Because we want to be able to build the test as a module, we need to + * iterate through all known tracepoints, since the static registration + * won't work here. + */ + for_each_kernel_tracepoint(register_tracepoints, NULL); return 0; } -static void kasan_test_exit(struct kunit *test) +static void kasan_suite_exit(struct kunit_suite *suite) { kasan_restore_multi_shot(multishot); - KUNIT_EXPECT_FALSE(test, test_status.report_found); + for_each_kernel_tracepoint(unregister_tracepoints, NULL); + tracepoint_synchronize_unregister(); +} + +static void kasan_test_exit(struct kunit *test) +{ + KUNIT_EXPECT_FALSE(test, READ_ONCE(test_status.report_found)); } /** @@ -106,11 +143,12 @@ static void kasan_test_exit(struct kunit *test) if (IS_ENABLED(CONFIG_KASAN_HW_TAGS) && \ kasan_sync_fault_possible()) { \ if (READ_ONCE(test_status.report_found) && \ - READ_ONCE(test_status.sync_fault)) \ + !READ_ONCE(test_status.async_fault)) \ kasan_enable_tagging(); \ migrate_enable(); \ } \ WRITE_ONCE(test_status.report_found, false); \ + WRITE_ONCE(test_status.async_fault, false); \ } while (0) #define KASAN_TEST_NEEDS_CONFIG_ON(test, config) do { \ @@ -1447,9 +1485,10 @@ static struct kunit_case kasan_kunit_test_cases[] = { static struct kunit_suite kasan_kunit_test_suite = { .name = "kasan", - .init = kasan_test_init, .test_cases = kasan_kunit_test_cases, .exit = kasan_test_exit, + .suite_init = kasan_suite_init, + .suite_exit = kasan_suite_exit, }; kunit_test_suite(kasan_kunit_test_suite); diff --git a/mm/kasan/report.c b/mm/kasan/report.c index df3602062bfd..31355851a5ec 100644 --- a/mm/kasan/report.c +++ b/mm/kasan/report.c @@ -30,8 +30,6 @@ #include -#include - #include "kasan.h" #include "../slab.h" @@ -114,41 +112,12 @@ EXPORT_SYMBOL_GPL(kasan_restore_multi_shot); #endif -#if IS_ENABLED(CONFIG_KASAN_KUNIT_TEST) -static void update_kunit_status(bool sync) -{ - struct kunit *test; - struct kunit_resource *resource; - struct kunit_kasan_status *status; - - test = current->kunit_test; - if (!test) - return; - - resource = kunit_find_named_resource(test, "kasan_status"); - if (!resource) { - kunit_set_failure(test); - return; - } - - status = (struct kunit_kasan_status *)resource->data; - WRITE_ONCE(status->report_found, true); - WRITE_ONCE(status->sync_fault, sync); - - kunit_put_resource(resource); -} -#else -static void update_kunit_status(bool sync) { } -#endif - static DEFINE_SPINLOCK(report_lock); static void start_report(unsigned long *flags, bool sync) { /* Respect the /proc/sys/kernel/traceoff_on_warning interface. */ disable_trace_on_warning(); - /* Update status of the currently running KASAN test. */ - update_kunit_status(sync); /* Do not allow LOCKDEP mangling KASAN reports. */ lockdep_off(); /* Make sure we don't end up in loop. */ -- cgit v1.2.3