kernel/kcsan/selftest.c - linux/kernel/git/torvalds/linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 /*
  * KCSAN short boot-time selftests.
  *
  * Copyright (C) 2019, Google LLC.
  */

 #define pr_fmt(fmt) "kcsan: " fmt

 #include <linux/atomic.h>
 #include <linux/bitops.h>
 #include <linux/init.h>
 #include <linux/kcsan-checks.h>
 #include <linux/kernel.h>
 #include <linux/printk.h>
 #include <linux/random.h>
 #include <linux/sched.h>
 #include <linux/spinlock.h>
 #include <linux/types.h>

 #include "encoding.h"

 #define ITERS_PER_TEST 2000

 /* Test requirements. */
 static bool __init test_requires(void)
 {
 	/* random should be initialized for the below tests */
 	return prandom_u32() + prandom_u32() != 0;
 }

 /*
  * Test watchpoint encode and decode: check that encoding some access's info,
  * and then subsequent decode preserves the access's info.
  */
 static bool __init test_encode_decode(void)
 {
 	int i;

 	for (i = 0; i < ITERS_PER_TEST; ++i) {
 		size_t size = prandom_u32_max(MAX_ENCODABLE_SIZE) + 1;
 		bool is_write = !!prandom_u32_max(2);
 		unsigned long verif_masked_addr;
 		long encoded_watchpoint;
 		bool verif_is_write;
 		unsigned long addr;
 		size_t verif_size;

 		prandom_bytes(&addr, sizeof(addr));
 		if (addr < PAGE_SIZE)
 			addr = PAGE_SIZE;

 		if (WARN_ON(!check_encodable(addr, size)))
 			return false;

 		encoded_watchpoint = encode_watchpoint(addr, size, is_write);

 		/* Check special watchpoints */
 		if (WARN_ON(decode_watchpoint(INVALID_WATCHPOINT, &verif_masked_addr, &verif_size, &verif_is_write)))
 			return false;
 		if (WARN_ON(decode_watchpoint(CONSUMED_WATCHPOINT, &verif_masked_addr, &verif_size, &verif_is_write)))
 			return false;

 		/* Check decoding watchpoint returns same data */
 		if (WARN_ON(!decode_watchpoint(encoded_watchpoint, &verif_masked_addr, &verif_size, &verif_is_write)))
 			return false;
 		if (WARN_ON(verif_masked_addr != (addr & WATCHPOINT_ADDR_MASK)))
 			goto fail;
 		if (WARN_ON(verif_size != size))
 			goto fail;
 		if (WARN_ON(is_write != verif_is_write))
 			goto fail;

 		continue;
 fail:
 		pr_err("%s fail: %s %zu bytes @ %lx -> encoded: %lx -> %s %zu bytes @ %lx\n",
 		       __func__, is_write ? "write" : "read", size, addr, encoded_watchpoint,
 		       verif_is_write ? "write" : "read", verif_size, verif_masked_addr);
 		return false;
 	}

 	return true;
 }

 /* Test access matching function. */
 static bool __init test_matching_access(void)
 {
 	if (WARN_ON(!matching_access(10, 1, 10, 1)))
 		return false;
 	if (WARN_ON(!matching_access(10, 2, 11, 1)))
 		return false;
 	if (WARN_ON(!matching_access(10, 1, 9, 2)))
 		return false;
 	if (WARN_ON(matching_access(10, 1, 11, 1)))
 		return false;
 	if (WARN_ON(matching_access(9, 1, 10, 1)))
 		return false;

 	/*
 	 * An access of size 0 could match another access, as demonstrated here.
 	 * Rather than add more comparisons to 'matching_access()', which would
 	 * end up in the fast-path for *all* checks, check_access() simply
 	 * returns for all accesses of size 0.
 	 */
 	if (WARN_ON(!matching_access(8, 8, 12, 0)))
 		return false;

 	return true;
 }

 /*
  * Correct memory barrier instrumentation is critical to avoiding false
  * positives: simple test to check at boot certain barriers are always properly
  * instrumented. See kcsan_test for a more complete test.
  */
 static DEFINE_SPINLOCK(test_spinlock);
 static bool __init test_barrier(void)
 {
 #ifdef CONFIG_KCSAN_WEAK_MEMORY
 	struct kcsan_scoped_access *reorder_access = &current->kcsan_ctx.reorder_access;
 #else
 	struct kcsan_scoped_access *reorder_access = NULL;
 #endif
 	bool ret = true;
 	arch_spinlock_t arch_spinlock = __ARCH_SPIN_LOCK_UNLOCKED;
 	atomic_t dummy;
 	long test_var;

 	if (!reorder_access || !IS_ENABLED(CONFIG_SMP))
 		return true;

 #define __KCSAN_CHECK_BARRIER(access_type, barrier, name)					\
 	do {											\
 		reorder_access->type = (access_type) | KCSAN_ACCESS_SCOPED;			\
 		reorder_access->size = 1;							\
 		barrier;									\
 		if (reorder_access->size != 0) {						\
 			pr_err("improperly instrumented type=(" #access_type "): " name "\n");	\
 			ret = false;								\
 		}										\
 	} while (0)
 #define KCSAN_CHECK_READ_BARRIER(b)  __KCSAN_CHECK_BARRIER(0, b, #b)
 #define KCSAN_CHECK_WRITE_BARRIER(b) __KCSAN_CHECK_BARRIER(KCSAN_ACCESS_WRITE, b, #b)
 #define KCSAN_CHECK_RW_BARRIER(b)    __KCSAN_CHECK_BARRIER(KCSAN_ACCESS_WRITE | KCSAN_ACCESS_COMPOUND, b, #b)

 	kcsan_nestable_atomic_begin(); /* No watchpoints in called functions. */

 	KCSAN_CHECK_READ_BARRIER(mb());
 	KCSAN_CHECK_READ_BARRIER(rmb());
 	KCSAN_CHECK_READ_BARRIER(smp_mb());
 	KCSAN_CHECK_READ_BARRIER(smp_rmb());
 	KCSAN_CHECK_READ_BARRIER(dma_rmb());
 	KCSAN_CHECK_READ_BARRIER(smp_mb__before_atomic());
 	KCSAN_CHECK_READ_BARRIER(smp_mb__after_atomic());
 	KCSAN_CHECK_READ_BARRIER(smp_mb__after_spinlock());
 	KCSAN_CHECK_READ_BARRIER(smp_store_mb(test_var, 0));
 	KCSAN_CHECK_READ_BARRIER(smp_store_release(&test_var, 0));
 	KCSAN_CHECK_READ_BARRIER(xchg(&test_var, 0));
 	KCSAN_CHECK_READ_BARRIER(xchg_release(&test_var, 0));
 	KCSAN_CHECK_READ_BARRIER(cmpxchg(&test_var, 0,  0));
 	KCSAN_CHECK_READ_BARRIER(cmpxchg_release(&test_var, 0,  0));
 	KCSAN_CHECK_READ_BARRIER(atomic_set_release(&dummy, 0));
 	KCSAN_CHECK_READ_BARRIER(atomic_add_return(1, &dummy));
 	KCSAN_CHECK_READ_BARRIER(atomic_add_return_release(1, &dummy));
 	KCSAN_CHECK_READ_BARRIER(atomic_fetch_add(1, &dummy));
 	KCSAN_CHECK_READ_BARRIER(atomic_fetch_add_release(1, &dummy));
 	KCSAN_CHECK_READ_BARRIER(test_and_set_bit(0, &test_var));
 	KCSAN_CHECK_READ_BARRIER(test_and_clear_bit(0, &test_var));
 	KCSAN_CHECK_READ_BARRIER(test_and_change_bit(0, &test_var));
 	KCSAN_CHECK_READ_BARRIER(clear_bit_unlock(0, &test_var));
 	KCSAN_CHECK_READ_BARRIER(__clear_bit_unlock(0, &test_var));
 	arch_spin_lock(&arch_spinlock);
 	KCSAN_CHECK_READ_BARRIER(arch_spin_unlock(&arch_spinlock));
 	spin_lock(&test_spinlock);
 	KCSAN_CHECK_READ_BARRIER(spin_unlock(&test_spinlock));

 	KCSAN_CHECK_WRITE_BARRIER(mb());
 	KCSAN_CHECK_WRITE_BARRIER(wmb());
 	KCSAN_CHECK_WRITE_BARRIER(smp_mb());
 	KCSAN_CHECK_WRITE_BARRIER(smp_wmb());
 	KCSAN_CHECK_WRITE_BARRIER(dma_wmb());
 	KCSAN_CHECK_WRITE_BARRIER(smp_mb__before_atomic());
 	KCSAN_CHECK_WRITE_BARRIER(smp_mb__after_atomic());
 	KCSAN_CHECK_WRITE_BARRIER(smp_mb__after_spinlock());
 	KCSAN_CHECK_WRITE_BARRIER(smp_store_mb(test_var, 0));
 	KCSAN_CHECK_WRITE_BARRIER(smp_store_release(&test_var, 0));
 	KCSAN_CHECK_WRITE_BARRIER(xchg(&test_var, 0));
 	KCSAN_CHECK_WRITE_BARRIER(xchg_release(&test_var, 0));
 	KCSAN_CHECK_WRITE_BARRIER(cmpxchg(&test_var, 0,  0));
 	KCSAN_CHECK_WRITE_BARRIER(cmpxchg_release(&test_var, 0,  0));
 	KCSAN_CHECK_WRITE_BARRIER(atomic_set_release(&dummy, 0));
 	KCSAN_CHECK_WRITE_BARRIER(atomic_add_return(1, &dummy));
 	KCSAN_CHECK_WRITE_BARRIER(atomic_add_return_release(1, &dummy));
 	KCSAN_CHECK_WRITE_BARRIER(atomic_fetch_add(1, &dummy));
 	KCSAN_CHECK_WRITE_BARRIER(atomic_fetch_add_release(1, &dummy));
 	KCSAN_CHECK_WRITE_BARRIER(test_and_set_bit(0, &test_var));
 	KCSAN_CHECK_WRITE_BARRIER(test_and_clear_bit(0, &test_var));
 	KCSAN_CHECK_WRITE_BARRIER(test_and_change_bit(0, &test_var));
 	KCSAN_CHECK_WRITE_BARRIER(clear_bit_unlock(0, &test_var));
 	KCSAN_CHECK_WRITE_BARRIER(__clear_bit_unlock(0, &test_var));
 	arch_spin_lock(&arch_spinlock);
 	KCSAN_CHECK_WRITE_BARRIER(arch_spin_unlock(&arch_spinlock));
 	spin_lock(&test_spinlock);
 	KCSAN_CHECK_WRITE_BARRIER(spin_unlock(&test_spinlock));

 	KCSAN_CHECK_RW_BARRIER(mb());
 	KCSAN_CHECK_RW_BARRIER(wmb());
 	KCSAN_CHECK_RW_BARRIER(rmb());
 	KCSAN_CHECK_RW_BARRIER(smp_mb());
 	KCSAN_CHECK_RW_BARRIER(smp_wmb());
 	KCSAN_CHECK_RW_BARRIER(smp_rmb());
 	KCSAN_CHECK_RW_BARRIER(dma_wmb());
 	KCSAN_CHECK_RW_BARRIER(dma_rmb());
 	KCSAN_CHECK_RW_BARRIER(smp_mb__before_atomic());
 	KCSAN_CHECK_RW_BARRIER(smp_mb__after_atomic());
 	KCSAN_CHECK_RW_BARRIER(smp_mb__after_spinlock());
 	KCSAN_CHECK_RW_BARRIER(smp_store_mb(test_var, 0));
 	KCSAN_CHECK_RW_BARRIER(smp_store_release(&test_var, 0));
 	KCSAN_CHECK_RW_BARRIER(xchg(&test_var, 0));
 	KCSAN_CHECK_RW_BARRIER(xchg_release(&test_var, 0));
 	KCSAN_CHECK_RW_BARRIER(cmpxchg(&test_var, 0,  0));
 	KCSAN_CHECK_RW_BARRIER(cmpxchg_release(&test_var, 0,  0));
 	KCSAN_CHECK_RW_BARRIER(atomic_set_release(&dummy, 0));
 	KCSAN_CHECK_RW_BARRIER(atomic_add_return(1, &dummy));
 	KCSAN_CHECK_RW_BARRIER(atomic_add_return_release(1, &dummy));
 	KCSAN_CHECK_RW_BARRIER(atomic_fetch_add(1, &dummy));
 	KCSAN_CHECK_RW_BARRIER(atomic_fetch_add_release(1, &dummy));
 	KCSAN_CHECK_RW_BARRIER(test_and_set_bit(0, &test_var));
 	KCSAN_CHECK_RW_BARRIER(test_and_clear_bit(0, &test_var));
 	KCSAN_CHECK_RW_BARRIER(test_and_change_bit(0, &test_var));
 	KCSAN_CHECK_RW_BARRIER(clear_bit_unlock(0, &test_var));
 	KCSAN_CHECK_RW_BARRIER(__clear_bit_unlock(0, &test_var));
 	arch_spin_lock(&arch_spinlock);
 	KCSAN_CHECK_RW_BARRIER(arch_spin_unlock(&arch_spinlock));
 	spin_lock(&test_spinlock);
 	KCSAN_CHECK_RW_BARRIER(spin_unlock(&test_spinlock));

 #ifdef clear_bit_unlock_is_negative_byte
 	KCSAN_CHECK_RW_BARRIER(clear_bit_unlock_is_negative_byte(0, &test_var));
 	KCSAN_CHECK_READ_BARRIER(clear_bit_unlock_is_negative_byte(0, &test_var));
 	KCSAN_CHECK_WRITE_BARRIER(clear_bit_unlock_is_negative_byte(0, &test_var));
 #endif
 	kcsan_nestable_atomic_end();

 	return ret;
 }

 static int __init kcsan_selftest(void)
 {
 	int passed = 0;
 	int total = 0;

 #define RUN_TEST(do_test)                                                      \
 	do {                                                                   \
 		++total;                                                       \
 		if (do_test())                                                 \
 			++passed;                                              \
 		else                                                           \
 			pr_err("selftest: " #do_test " failed");               \
 	} while (0)

 	RUN_TEST(test_requires);
 	RUN_TEST(test_encode_decode);
 	RUN_TEST(test_matching_access);
 	RUN_TEST(test_barrier);

 	pr_info("selftest: %d/%d tests passed\n", passed, total);
 	if (passed != total)
 		panic("selftests failed");
 	return 0;
 }
 postcore_initcall(kcsan_selftest);
	// SPDX-License-Identifier: GPL-2.0
	/*
	* KCSAN short boot-time selftests.
	*
	* Copyright (C) 2019, Google LLC.
	*/

	#define pr_fmt(fmt) "kcsan: " fmt

	#include <linux/atomic.h>
	#include <linux/bitops.h>
	#include <linux/init.h>
	#include <linux/kcsan-checks.h>
	#include <linux/kernel.h>
	#include <linux/printk.h>
	#include <linux/random.h>
	#include <linux/sched.h>
	#include <linux/spinlock.h>
	#include <linux/types.h>

	#include "encoding.h"

	#define ITERS_PER_TEST 2000

	/* Test requirements. */
	static bool __init test_requires(void)
	{
	/* random should be initialized for the below tests */
	return prandom_u32() + prandom_u32() != 0;
	}

	/*
	* Test watchpoint encode and decode: check that encoding some access's info,
	* and then subsequent decode preserves the access's info.
	*/
	static bool __init test_encode_decode(void)
	{
	int i;

	for (i = 0; i < ITERS_PER_TEST; ++i) {
	size_t size = prandom_u32_max(MAX_ENCODABLE_SIZE) + 1;
	bool is_write = !!prandom_u32_max(2);
	unsigned long verif_masked_addr;
	long encoded_watchpoint;
	bool verif_is_write;
	unsigned long addr;
	size_t verif_size;

	prandom_bytes(&addr, sizeof(addr));
	if (addr < PAGE_SIZE)
	addr = PAGE_SIZE;

	if (WARN_ON(!check_encodable(addr, size)))
	return false;

	encoded_watchpoint = encode_watchpoint(addr, size, is_write);

	/* Check special watchpoints */
	if (WARN_ON(decode_watchpoint(INVALID_WATCHPOINT, &verif_masked_addr, &verif_size, &verif_is_write)))
	return false;
	if (WARN_ON(decode_watchpoint(CONSUMED_WATCHPOINT, &verif_masked_addr, &verif_size, &verif_is_write)))
	return false;

	/* Check decoding watchpoint returns same data */
	if (WARN_ON(!decode_watchpoint(encoded_watchpoint, &verif_masked_addr, &verif_size, &verif_is_write)))
	return false;
	if (WARN_ON(verif_masked_addr != (addr & WATCHPOINT_ADDR_MASK)))
	goto fail;
	if (WARN_ON(verif_size != size))
	goto fail;
	if (WARN_ON(is_write != verif_is_write))
	goto fail;

	continue;
	fail:
	pr_err("%s fail: %s %zu bytes @ %lx -> encoded: %lx -> %s %zu bytes @ %lx\n",
	__func__, is_write ? "write" : "read", size, addr, encoded_watchpoint,
	verif_is_write ? "write" : "read", verif_size, verif_masked_addr);
	return false;
	}

	return true;
	}

	/* Test access matching function. */
	static bool __init test_matching_access(void)
	{
	if (WARN_ON(!matching_access(10, 1, 10, 1)))
	return false;
	if (WARN_ON(!matching_access(10, 2, 11, 1)))
	return false;
	if (WARN_ON(!matching_access(10, 1, 9, 2)))
	return false;
	if (WARN_ON(matching_access(10, 1, 11, 1)))
	return false;
	if (WARN_ON(matching_access(9, 1, 10, 1)))
	return false;

	/*
	* An access of size 0 could match another access, as demonstrated here.
	* Rather than add more comparisons to 'matching_access()', which would
	* end up in the fast-path for all checks, check_access() simply
	* returns for all accesses of size 0.
	*/
	if (WARN_ON(!matching_access(8, 8, 12, 0)))
	return false;

	return true;
	}

	/*
	* Correct memory barrier instrumentation is critical to avoiding false
	* positives: simple test to check at boot certain barriers are always properly
	* instrumented. See kcsan_test for a more complete test.
	*/
	static DEFINE_SPINLOCK(test_spinlock);
	static bool __init test_barrier(void)
	{
	#ifdef CONFIG_KCSAN_WEAK_MEMORY
	struct kcsan_scoped_access *reorder_access = &current->kcsan_ctx.reorder_access;
	#else
	struct kcsan_scoped_access *reorder_access = NULL;
	#endif
	bool ret = true;
	arch_spinlock_t arch_spinlock = __ARCH_SPIN_LOCK_UNLOCKED;
	atomic_t dummy;
	long test_var;

	if (!reorder_access \|\| !IS_ENABLED(CONFIG_SMP))
	return true;

	#define __KCSAN_CHECK_BARRIER(access_type, barrier, name) \
	do { \
	reorder_access->type = (access_type) \| KCSAN_ACCESS_SCOPED; \
	reorder_access->size = 1; \
	barrier; \
	if (reorder_access->size != 0) { \
	pr_err("improperly instrumented type=(" #access_type "): " name "\n"); \
	ret = false; \
	} \
	} while (0)
	#define KCSAN_CHECK_READ_BARRIER(b) __KCSAN_CHECK_BARRIER(0, b, #b)
	#define KCSAN_CHECK_WRITE_BARRIER(b) __KCSAN_CHECK_BARRIER(KCSAN_ACCESS_WRITE, b, #b)
	#define KCSAN_CHECK_RW_BARRIER(b) __KCSAN_CHECK_BARRIER(KCSAN_ACCESS_WRITE \| KCSAN_ACCESS_COMPOUND, b, #b)

	kcsan_nestable_atomic_begin(); /* No watchpoints in called functions. */

	KCSAN_CHECK_READ_BARRIER(mb());
	KCSAN_CHECK_READ_BARRIER(rmb());
	KCSAN_CHECK_READ_BARRIER(smp_mb());
	KCSAN_CHECK_READ_BARRIER(smp_rmb());
	KCSAN_CHECK_READ_BARRIER(dma_rmb());
	KCSAN_CHECK_READ_BARRIER(smp_mb__before_atomic());
	KCSAN_CHECK_READ_BARRIER(smp_mb__after_atomic());
	KCSAN_CHECK_READ_BARRIER(smp_mb__after_spinlock());
	KCSAN_CHECK_READ_BARRIER(smp_store_mb(test_var, 0));
	KCSAN_CHECK_READ_BARRIER(smp_store_release(&test_var, 0));
	KCSAN_CHECK_READ_BARRIER(xchg(&test_var, 0));
	KCSAN_CHECK_READ_BARRIER(xchg_release(&test_var, 0));
	KCSAN_CHECK_READ_BARRIER(cmpxchg(&test_var, 0, 0));
	KCSAN_CHECK_READ_BARRIER(cmpxchg_release(&test_var, 0, 0));
	KCSAN_CHECK_READ_BARRIER(atomic_set_release(&dummy, 0));
	KCSAN_CHECK_READ_BARRIER(atomic_add_return(1, &dummy));
	KCSAN_CHECK_READ_BARRIER(atomic_add_return_release(1, &dummy));
	KCSAN_CHECK_READ_BARRIER(atomic_fetch_add(1, &dummy));
	KCSAN_CHECK_READ_BARRIER(atomic_fetch_add_release(1, &dummy));
	KCSAN_CHECK_READ_BARRIER(test_and_set_bit(0, &test_var));
	KCSAN_CHECK_READ_BARRIER(test_and_clear_bit(0, &test_var));
	KCSAN_CHECK_READ_BARRIER(test_and_change_bit(0, &test_var));
	KCSAN_CHECK_READ_BARRIER(clear_bit_unlock(0, &test_var));
	KCSAN_CHECK_READ_BARRIER(__clear_bit_unlock(0, &test_var));
	arch_spin_lock(&arch_spinlock);
	KCSAN_CHECK_READ_BARRIER(arch_spin_unlock(&arch_spinlock));
	spin_lock(&test_spinlock);
	KCSAN_CHECK_READ_BARRIER(spin_unlock(&test_spinlock));

	KCSAN_CHECK_WRITE_BARRIER(mb());
	KCSAN_CHECK_WRITE_BARRIER(wmb());
	KCSAN_CHECK_WRITE_BARRIER(smp_mb());
	KCSAN_CHECK_WRITE_BARRIER(smp_wmb());
	KCSAN_CHECK_WRITE_BARRIER(dma_wmb());
	KCSAN_CHECK_WRITE_BARRIER(smp_mb__before_atomic());
	KCSAN_CHECK_WRITE_BARRIER(smp_mb__after_atomic());
	KCSAN_CHECK_WRITE_BARRIER(smp_mb__after_spinlock());
	KCSAN_CHECK_WRITE_BARRIER(smp_store_mb(test_var, 0));
	KCSAN_CHECK_WRITE_BARRIER(smp_store_release(&test_var, 0));
	KCSAN_CHECK_WRITE_BARRIER(xchg(&test_var, 0));
	KCSAN_CHECK_WRITE_BARRIER(xchg_release(&test_var, 0));
	KCSAN_CHECK_WRITE_BARRIER(cmpxchg(&test_var, 0, 0));
	KCSAN_CHECK_WRITE_BARRIER(cmpxchg_release(&test_var, 0, 0));
	KCSAN_CHECK_WRITE_BARRIER(atomic_set_release(&dummy, 0));
	KCSAN_CHECK_WRITE_BARRIER(atomic_add_return(1, &dummy));
	KCSAN_CHECK_WRITE_BARRIER(atomic_add_return_release(1, &dummy));
	KCSAN_CHECK_WRITE_BARRIER(atomic_fetch_add(1, &dummy));
	KCSAN_CHECK_WRITE_BARRIER(atomic_fetch_add_release(1, &dummy));
	KCSAN_CHECK_WRITE_BARRIER(test_and_set_bit(0, &test_var));
	KCSAN_CHECK_WRITE_BARRIER(test_and_clear_bit(0, &test_var));
	KCSAN_CHECK_WRITE_BARRIER(test_and_change_bit(0, &test_var));
	KCSAN_CHECK_WRITE_BARRIER(clear_bit_unlock(0, &test_var));
	KCSAN_CHECK_WRITE_BARRIER(__clear_bit_unlock(0, &test_var));
	arch_spin_lock(&arch_spinlock);
	KCSAN_CHECK_WRITE_BARRIER(arch_spin_unlock(&arch_spinlock));
	spin_lock(&test_spinlock);
	KCSAN_CHECK_WRITE_BARRIER(spin_unlock(&test_spinlock));

	KCSAN_CHECK_RW_BARRIER(mb());
	KCSAN_CHECK_RW_BARRIER(wmb());
	KCSAN_CHECK_RW_BARRIER(rmb());
	KCSAN_CHECK_RW_BARRIER(smp_mb());
	KCSAN_CHECK_RW_BARRIER(smp_wmb());
	KCSAN_CHECK_RW_BARRIER(smp_rmb());
	KCSAN_CHECK_RW_BARRIER(dma_wmb());
	KCSAN_CHECK_RW_BARRIER(dma_rmb());
	KCSAN_CHECK_RW_BARRIER(smp_mb__before_atomic());
	KCSAN_CHECK_RW_BARRIER(smp_mb__after_atomic());
	KCSAN_CHECK_RW_BARRIER(smp_mb__after_spinlock());
	KCSAN_CHECK_RW_BARRIER(smp_store_mb(test_var, 0));
	KCSAN_CHECK_RW_BARRIER(smp_store_release(&test_var, 0));
	KCSAN_CHECK_RW_BARRIER(xchg(&test_var, 0));
	KCSAN_CHECK_RW_BARRIER(xchg_release(&test_var, 0));
	KCSAN_CHECK_RW_BARRIER(cmpxchg(&test_var, 0, 0));
	KCSAN_CHECK_RW_BARRIER(cmpxchg_release(&test_var, 0, 0));
	KCSAN_CHECK_RW_BARRIER(atomic_set_release(&dummy, 0));
	KCSAN_CHECK_RW_BARRIER(atomic_add_return(1, &dummy));
	KCSAN_CHECK_RW_BARRIER(atomic_add_return_release(1, &dummy));
	KCSAN_CHECK_RW_BARRIER(atomic_fetch_add(1, &dummy));
	KCSAN_CHECK_RW_BARRIER(atomic_fetch_add_release(1, &dummy));
	KCSAN_CHECK_RW_BARRIER(test_and_set_bit(0, &test_var));
	KCSAN_CHECK_RW_BARRIER(test_and_clear_bit(0, &test_var));
	KCSAN_CHECK_RW_BARRIER(test_and_change_bit(0, &test_var));
	KCSAN_CHECK_RW_BARRIER(clear_bit_unlock(0, &test_var));
	KCSAN_CHECK_RW_BARRIER(__clear_bit_unlock(0, &test_var));
	arch_spin_lock(&arch_spinlock);
	KCSAN_CHECK_RW_BARRIER(arch_spin_unlock(&arch_spinlock));
	spin_lock(&test_spinlock);
	KCSAN_CHECK_RW_BARRIER(spin_unlock(&test_spinlock));

	#ifdef clear_bit_unlock_is_negative_byte
	KCSAN_CHECK_RW_BARRIER(clear_bit_unlock_is_negative_byte(0, &test_var));
	KCSAN_CHECK_READ_BARRIER(clear_bit_unlock_is_negative_byte(0, &test_var));
	KCSAN_CHECK_WRITE_BARRIER(clear_bit_unlock_is_negative_byte(0, &test_var));
	#endif
	kcsan_nestable_atomic_end();

	return ret;
	}

	static int __init kcsan_selftest(void)
	{
	int passed = 0;
	int total = 0;

	#define RUN_TEST(do_test) \
	do { \
	++total; \
	if (do_test()) \
	++passed; \
	else \
	pr_err("selftest: " #do_test " failed"); \
	} while (0)

	RUN_TEST(test_requires);
	RUN_TEST(test_encode_decode);
	RUN_TEST(test_matching_access);
	RUN_TEST(test_barrier);

	pr_info("selftest: %d/%d tests passed\n", passed, total);
	if (passed != total)
	panic("selftests failed");
	return 0;
	}
	postcore_initcall(kcsan_selftest);