kcsan: Test support for compound instrumentation (bec4a247) · Commits · 戴 / test

kernel/kcsan/kcsan-test.c

+51 −14

Original line number	Diff line number	Diff line
		@@ -27,6 +27,12 @@
		#include <linux/types.h>
		#include <trace/events/printk.h>

		#ifdef CONFIG_CC_HAS_TSAN_COMPOUND_READ_BEFORE_WRITE
		#define __KCSAN_ACCESS_RW(alt) (KCSAN_ACCESS_COMPOUND \| KCSAN_ACCESS_WRITE)
		#else
		#define __KCSAN_ACCESS_RW(alt) (alt)
		#endif

		/* Points to current test-case memory access "kernels". */
		static void (*access_kernels[2])(void);

		@@ -186,20 +192,21 @@ static bool report_matches(const struct expect_report *r)

		/* Access 1 & 2 */
		for (i = 0; i < 2; ++i) {
		const int ty = r->access[i].type;
		const char *const access_type =
		(r->access[i].type & KCSAN_ACCESS_ASSERT) ?
		((r->access[i].type & KCSAN_ACCESS_WRITE) ?
		(ty & KCSAN_ACCESS_ASSERT) ?
		((ty & KCSAN_ACCESS_WRITE) ?
		"assert no accesses" :
		"assert no writes") :
		((r->access[i].type & KCSAN_ACCESS_WRITE) ?
		"write" :
		((ty & KCSAN_ACCESS_WRITE) ?
		((ty & KCSAN_ACCESS_COMPOUND) ?
		"read-write" :
		"write") :
		"read");
		const char *const access_type_aux =
		(r->access[i].type & KCSAN_ACCESS_ATOMIC) ?
		(ty & KCSAN_ACCESS_ATOMIC) ?
		" (marked)" :
		((r->access[i].type & KCSAN_ACCESS_SCOPED) ?
		" (scoped)" :
		"");
		((ty & KCSAN_ACCESS_SCOPED) ? " (scoped)" : "");

		if (i == 1) {
		/* Access 2 */
		@@ -277,6 +284,12 @@ static noinline void test_kernel_write_atomic(void)
		WRITE_ONCE(test_var, READ_ONCE_NOCHECK(test_sink) + 1);
		}

		static noinline void test_kernel_atomic_rmw(void)
		{
		/* Use builtin, so we can set up the "bad" atomic/non-atomic scenario. */
		__atomic_fetch_add(&test_var, 1, __ATOMIC_RELAXED);
		}

		__no_kcsan
		static noinline void test_kernel_write_uninstrumented(void) { test_var++; }

		@@ -439,8 +452,8 @@ static void test_concurrent_races(struct kunit *test)
		const struct expect_report expect = {
		.access = {
		/* NULL will match any address. */
		{ test_kernel_rmw_array, NULL, 0, KCSAN_ACCESS_WRITE },
		{ test_kernel_rmw_array, NULL, 0, 0 },
		{ test_kernel_rmw_array, NULL, 0, __KCSAN_ACCESS_RW(KCSAN_ACCESS_WRITE) },
		{ test_kernel_rmw_array, NULL, 0, __KCSAN_ACCESS_RW(0) },
		},
		};
		static const struct expect_report never = {
		@@ -629,6 +642,29 @@ static void test_read_plain_atomic_write(struct kunit *test)
		KUNIT_EXPECT_TRUE(test, match_expect);
		}

		/* Test that atomic RMWs generate correct report. */
		__no_kcsan
		static void test_read_plain_atomic_rmw(struct kunit *test)
		{
		const struct expect_report expect = {
		.access = {
		{ test_kernel_read, &test_var, sizeof(test_var), 0 },
		{ test_kernel_atomic_rmw, &test_var, sizeof(test_var),
		KCSAN_ACCESS_COMPOUND \| KCSAN_ACCESS_WRITE \| KCSAN_ACCESS_ATOMIC },
		},
		};
		bool match_expect = false;

		if (IS_ENABLED(CONFIG_KCSAN_IGNORE_ATOMICS))
		return;

		begin_test_checks(test_kernel_read, test_kernel_atomic_rmw);
		do {
		match_expect = report_matches(&expect);
		} while (!end_test_checks(match_expect));
		KUNIT_EXPECT_TRUE(test, match_expect);
		}

		/* Zero-sized accesses should never cause data race reports. */
		__no_kcsan
		static void test_zero_size_access(struct kunit *test)
		@@ -942,6 +978,7 @@ static struct kunit_case kcsan_test_cases[] = {
		KCSAN_KUNIT_CASE(test_write_write_struct_part),
		KCSAN_KUNIT_CASE(test_read_atomic_write_atomic),
		KCSAN_KUNIT_CASE(test_read_plain_atomic_write),
		KCSAN_KUNIT_CASE(test_read_plain_atomic_rmw),
		KCSAN_KUNIT_CASE(test_zero_size_access),
		KCSAN_KUNIT_CASE(test_data_race),
		KCSAN_KUNIT_CASE(test_assert_exclusive_writer),

lib/Kconfig.kcsan

+5 −0

Original line number	Diff line number	Diff line
		@@ -40,6 +40,11 @@ menuconfig KCSAN

		if KCSAN

		# Compiler capabilities that should not fail the test if they are unavailable.
		config CC_HAS_TSAN_COMPOUND_READ_BEFORE_WRITE
		def_bool (CC_IS_CLANG && $(cc-option,-fsanitize=thread -mllvm -tsan-compound-read-before-write=1)) \|\| \
		(CC_IS_GCC && $(cc-option,-fsanitize=thread --param tsan-compound-read-before-write=1))

		config KCSAN_VERBOSE
		bool "Show verbose reports with more information about system state"
		depends on PROVE_LOCKING

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