| // SPDX-License-Identifier: GPL-2.0 |
| /* |
| * KCSAN test with various race scenarious to test runtime behaviour. Since the |
| * interface with which KCSAN's reports are obtained is via the console, this is |
| * the output we should verify. For each test case checks the presence (or |
| * absence) of generated reports. Relies on 'console' tracepoint to capture |
| * reports as they appear in the kernel log. |
| * |
| * Makes use of KUnit for test organization, and the Torture framework for test |
| * thread control. |
| * |
| * Copyright (C) 2020, Google LLC. |
| * Author: Marco Elver <elver@google.com> |
| */ |
| |
| #define pr_fmt(fmt) "kcsan_test: " fmt |
| |
| #include <kunit/test.h> |
| #include <linux/atomic.h> |
| #include <linux/bitops.h> |
| #include <linux/jiffies.h> |
| #include <linux/kcsan-checks.h> |
| #include <linux/kernel.h> |
| #include <linux/mutex.h> |
| #include <linux/sched.h> |
| #include <linux/seqlock.h> |
| #include <linux/spinlock.h> |
| #include <linux/string.h> |
| #include <linux/timer.h> |
| #include <linux/torture.h> |
| #include <linux/tracepoint.h> |
| #include <linux/types.h> |
| #include <trace/events/printk.h> |
| |
| #define KCSAN_TEST_REQUIRES(test, cond) do { \ |
| if (!(cond)) \ |
| kunit_skip((test), "Test requires: " #cond); \ |
| } while (0) |
| |
| #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); |
| |
| static struct task_struct **threads; /* Lists of threads. */ |
| static unsigned long end_time; /* End time of test. */ |
| |
| /* Report as observed from console. */ |
| static struct { |
| spinlock_t lock; |
| int nlines; |
| char lines[3][512]; |
| } observed = { |
| .lock = __SPIN_LOCK_UNLOCKED(observed.lock), |
| }; |
| |
| /* Setup test checking loop. */ |
| static __no_kcsan inline void |
| begin_test_checks(void (*func1)(void), void (*func2)(void)) |
| { |
| kcsan_disable_current(); |
| |
| /* |
| * Require at least as long as KCSAN_REPORT_ONCE_IN_MS, to ensure at |
| * least one race is reported. |
| */ |
| end_time = jiffies + msecs_to_jiffies(CONFIG_KCSAN_REPORT_ONCE_IN_MS + 500); |
| |
| /* Signal start; release potential initialization of shared data. */ |
| smp_store_release(&access_kernels[0], func1); |
| smp_store_release(&access_kernels[1], func2); |
| } |
| |
| /* End test checking loop. */ |
| static __no_kcsan inline bool |
| end_test_checks(bool stop) |
| { |
| if (!stop && time_before(jiffies, end_time)) { |
| /* Continue checking */ |
| might_sleep(); |
| return false; |
| } |
| |
| kcsan_enable_current(); |
| return true; |
| } |
| |
| /* |
| * Probe for console output: checks if a race was reported, and obtains observed |
| * lines of interest. |
| */ |
| __no_kcsan |
| static void probe_console(void *ignore, const char *buf, size_t len) |
| { |
| unsigned long flags; |
| int nlines; |
| |
| /* |
| * Note that KCSAN reports under a global lock, so we do not risk the |
| * possibility of having multiple reports interleaved. If that were the |
| * case, we'd expect tests to fail. |
| */ |
| |
| spin_lock_irqsave(&observed.lock, flags); |
| nlines = observed.nlines; |
| |
| if (strnstr(buf, "BUG: KCSAN: ", len) && strnstr(buf, "test_", len)) { |
| /* |
| * KCSAN report and related to the test. |
| * |
| * The provided @buf is not NUL-terminated; copy no more than |
| * @len bytes and let strscpy() add the missing NUL-terminator. |
| */ |
| strscpy(observed.lines[0], buf, min(len + 1, sizeof(observed.lines[0]))); |
| nlines = 1; |
| } else if ((nlines == 1 || nlines == 2) && strnstr(buf, "bytes by", len)) { |
| strscpy(observed.lines[nlines++], buf, min(len + 1, sizeof(observed.lines[0]))); |
| |
| if (strnstr(buf, "race at unknown origin", len)) { |
| if (WARN_ON(nlines != 2)) |
| goto out; |
| |
| /* No second line of interest. */ |
| strcpy(observed.lines[nlines++], "<none>"); |
| } |
| } |
| |
| out: |
| WRITE_ONCE(observed.nlines, nlines); /* Publish new nlines. */ |
| spin_unlock_irqrestore(&observed.lock, flags); |
| } |
| |
| /* Check if a report related to the test exists. */ |
| __no_kcsan |
| static bool report_available(void) |
| { |
| return READ_ONCE(observed.nlines) == ARRAY_SIZE(observed.lines); |
| } |
| |
| /* Report information we expect in a report. */ |
| struct expect_report { |
| /* Access information of both accesses. */ |
| struct { |
| void *fn; /* Function pointer to expected function of top frame. */ |
| void *addr; /* Address of access; unchecked if NULL. */ |
| size_t size; /* Size of access; unchecked if @addr is NULL. */ |
| int type; /* Access type, see KCSAN_ACCESS definitions. */ |
| } access[2]; |
| }; |
| |
| /* Check observed report matches information in @r. */ |
| __no_kcsan |
| static bool __report_matches(const struct expect_report *r) |
| { |
| const bool is_assert = (r->access[0].type | r->access[1].type) & KCSAN_ACCESS_ASSERT; |
| bool ret = false; |
| unsigned long flags; |
| typeof(observed.lines) expect; |
| const char *end; |
| char *cur; |
| int i; |
| |
| /* Doubled-checked locking. */ |
| if (!report_available()) |
| return false; |
| |
| /* Generate expected report contents. */ |
| |
| /* Title */ |
| cur = expect[0]; |
| end = &expect[0][sizeof(expect[0]) - 1]; |
| cur += scnprintf(cur, end - cur, "BUG: KCSAN: %s in ", |
| is_assert ? "assert: race" : "data-race"); |
| if (r->access[1].fn) { |
| char tmp[2][64]; |
| int cmp; |
| |
| /* Expect lexographically sorted function names in title. */ |
| scnprintf(tmp[0], sizeof(tmp[0]), "%pS", r->access[0].fn); |
| scnprintf(tmp[1], sizeof(tmp[1]), "%pS", r->access[1].fn); |
| cmp = strcmp(tmp[0], tmp[1]); |
| cur += scnprintf(cur, end - cur, "%ps / %ps", |
| cmp < 0 ? r->access[0].fn : r->access[1].fn, |
| cmp < 0 ? r->access[1].fn : r->access[0].fn); |
| } else { |
| scnprintf(cur, end - cur, "%pS", r->access[0].fn); |
| /* The exact offset won't match, remove it. */ |
| cur = strchr(expect[0], '+'); |
| if (cur) |
| *cur = '\0'; |
| } |
| |
| /* Access 1 */ |
| cur = expect[1]; |
| end = &expect[1][sizeof(expect[1]) - 1]; |
| if (!r->access[1].fn) |
| cur += scnprintf(cur, end - cur, "race at unknown origin, with "); |
| |
| /* Access 1 & 2 */ |
| for (i = 0; i < 2; ++i) { |
| const int ty = r->access[i].type; |
| const char *const access_type = |
| (ty & KCSAN_ACCESS_ASSERT) ? |
| ((ty & KCSAN_ACCESS_WRITE) ? |
| "assert no accesses" : |
| "assert no writes") : |
| ((ty & KCSAN_ACCESS_WRITE) ? |
| ((ty & KCSAN_ACCESS_COMPOUND) ? |
| "read-write" : |
| "write") : |
| "read"); |
| const bool is_atomic = (ty & KCSAN_ACCESS_ATOMIC); |
| const bool is_scoped = (ty & KCSAN_ACCESS_SCOPED); |
| const char *const access_type_aux = |
| (is_atomic && is_scoped) ? " (marked, reordered)" |
| : (is_atomic ? " (marked)" |
| : (is_scoped ? " (reordered)" : "")); |
| |
| if (i == 1) { |
| /* Access 2 */ |
| cur = expect[2]; |
| end = &expect[2][sizeof(expect[2]) - 1]; |
| |
| if (!r->access[1].fn) { |
| /* Dummy string if no second access is available. */ |
| strcpy(cur, "<none>"); |
| break; |
| } |
| } |
| |
| cur += scnprintf(cur, end - cur, "%s%s to ", access_type, |
| access_type_aux); |
| |
| if (r->access[i].addr) /* Address is optional. */ |
| cur += scnprintf(cur, end - cur, "0x%px of %zu bytes", |
| r->access[i].addr, r->access[i].size); |
| } |
| |
| spin_lock_irqsave(&observed.lock, flags); |
| if (!report_available()) |
| goto out; /* A new report is being captured. */ |
| |
| /* Finally match expected output to what we actually observed. */ |
| ret = strstr(observed.lines[0], expect[0]) && |
| /* Access info may appear in any order. */ |
| ((strstr(observed.lines[1], expect[1]) && |
| strstr(observed.lines[2], expect[2])) || |
| (strstr(observed.lines[1], expect[2]) && |
| strstr(observed.lines[2], expect[1]))); |
| out: |
| spin_unlock_irqrestore(&observed.lock, flags); |
| return ret; |
| } |
| |
| static __always_inline const struct expect_report * |
| __report_set_scoped(struct expect_report *r, int accesses) |
| { |
| BUILD_BUG_ON(accesses > 3); |
| |
| if (accesses & 1) |
| r->access[0].type |= KCSAN_ACCESS_SCOPED; |
| else |
| r->access[0].type &= ~KCSAN_ACCESS_SCOPED; |
| |
| if (accesses & 2) |
| r->access[1].type |= KCSAN_ACCESS_SCOPED; |
| else |
| r->access[1].type &= ~KCSAN_ACCESS_SCOPED; |
| |
| return r; |
| } |
| |
| __no_kcsan |
| static bool report_matches_any_reordered(struct expect_report *r) |
| { |
| return __report_matches(__report_set_scoped(r, 0)) || |
| __report_matches(__report_set_scoped(r, 1)) || |
| __report_matches(__report_set_scoped(r, 2)) || |
| __report_matches(__report_set_scoped(r, 3)); |
| } |
| |
| #ifdef CONFIG_KCSAN_WEAK_MEMORY |
| /* Due to reordering accesses, any access may appear as "(reordered)". */ |
| #define report_matches report_matches_any_reordered |
| #else |
| #define report_matches __report_matches |
| #endif |
| |
| /* ===== Test kernels ===== */ |
| |
| static long test_sink; |
| static long test_var; |
| /* @test_array should be large enough to fall into multiple watchpoint slots. */ |
| static long test_array[3 * PAGE_SIZE / sizeof(long)]; |
| static struct { |
| long val[8]; |
| } test_struct; |
| static DEFINE_SEQLOCK(test_seqlock); |
| static DEFINE_SPINLOCK(test_spinlock); |
| static DEFINE_MUTEX(test_mutex); |
| |
| /* |
| * Helper to avoid compiler optimizing out reads, and to generate source values |
| * for writes. |
| */ |
| __no_kcsan |
| static noinline void sink_value(long v) { WRITE_ONCE(test_sink, v); } |
| |
| /* |
| * Generates a delay and some accesses that enter the runtime but do not produce |
| * data races. |
| */ |
| static noinline void test_delay(int iter) |
| { |
| while (iter--) |
| sink_value(READ_ONCE(test_sink)); |
| } |
| |
| static noinline void test_kernel_read(void) { sink_value(test_var); } |
| |
| static noinline void test_kernel_write(void) |
| { |
| test_var = READ_ONCE_NOCHECK(test_sink) + 1; |
| } |
| |
| static noinline void test_kernel_write_nochange(void) { test_var = 42; } |
| |
| /* Suffixed by value-change exception filter. */ |
| static noinline void test_kernel_write_nochange_rcu(void) { test_var = 42; } |
| |
| static noinline void test_kernel_read_atomic(void) |
| { |
| sink_value(READ_ONCE(test_var)); |
| } |
| |
| 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++; } |
| |
| static noinline void test_kernel_data_race(void) { data_race(test_var++); } |
| |
| static noinline void test_kernel_assert_writer(void) |
| { |
| ASSERT_EXCLUSIVE_WRITER(test_var); |
| } |
| |
| static noinline void test_kernel_assert_access(void) |
| { |
| ASSERT_EXCLUSIVE_ACCESS(test_var); |
| } |
| |
| #define TEST_CHANGE_BITS 0xff00ff00 |
| |
| static noinline void test_kernel_change_bits(void) |
| { |
| if (IS_ENABLED(CONFIG_KCSAN_IGNORE_ATOMICS)) { |
| /* |
| * Avoid race of unknown origin for this test, just pretend they |
| * are atomic. |
| */ |
| kcsan_nestable_atomic_begin(); |
| test_var ^= TEST_CHANGE_BITS; |
| kcsan_nestable_atomic_end(); |
| } else |
| WRITE_ONCE(test_var, READ_ONCE(test_var) ^ TEST_CHANGE_BITS); |
| } |
| |
| static noinline void test_kernel_assert_bits_change(void) |
| { |
| ASSERT_EXCLUSIVE_BITS(test_var, TEST_CHANGE_BITS); |
| } |
| |
| static noinline void test_kernel_assert_bits_nochange(void) |
| { |
| ASSERT_EXCLUSIVE_BITS(test_var, ~TEST_CHANGE_BITS); |
| } |
| |
| /* |
| * Scoped assertions do trigger anywhere in scope. However, the report should |
| * still only point at the start of the scope. |
| */ |
| static noinline void test_enter_scope(void) |
| { |
| int x = 0; |
| |
| /* Unrelated accesses to scoped assert. */ |
| READ_ONCE(test_sink); |
| kcsan_check_read(&x, sizeof(x)); |
| } |
| |
| static noinline void test_kernel_assert_writer_scoped(void) |
| { |
| ASSERT_EXCLUSIVE_WRITER_SCOPED(test_var); |
| test_enter_scope(); |
| } |
| |
| static noinline void test_kernel_assert_access_scoped(void) |
| { |
| ASSERT_EXCLUSIVE_ACCESS_SCOPED(test_var); |
| test_enter_scope(); |
| } |
| |
| static noinline void test_kernel_rmw_array(void) |
| { |
| int i; |
| |
| for (i = 0; i < ARRAY_SIZE(test_array); ++i) |
| test_array[i]++; |
| } |
| |
| static noinline void test_kernel_write_struct(void) |
| { |
| kcsan_check_write(&test_struct, sizeof(test_struct)); |
| kcsan_disable_current(); |
| test_struct.val[3]++; /* induce value change */ |
| kcsan_enable_current(); |
| } |
| |
| static noinline void test_kernel_write_struct_part(void) |
| { |
| test_struct.val[3] = 42; |
| } |
| |
| static noinline void test_kernel_read_struct_zero_size(void) |
| { |
| kcsan_check_read(&test_struct.val[3], 0); |
| } |
| |
| static noinline void test_kernel_jiffies_reader(void) |
| { |
| sink_value((long)jiffies); |
| } |
| |
| static noinline void test_kernel_seqlock_reader(void) |
| { |
| unsigned int seq; |
| |
| do { |
| seq = read_seqbegin(&test_seqlock); |
| sink_value(test_var); |
| } while (read_seqretry(&test_seqlock, seq)); |
| } |
| |
| static noinline void test_kernel_seqlock_writer(void) |
| { |
| unsigned long flags; |
| |
| write_seqlock_irqsave(&test_seqlock, flags); |
| test_var++; |
| write_sequnlock_irqrestore(&test_seqlock, flags); |
| } |
| |
| static noinline void test_kernel_atomic_builtins(void) |
| { |
| /* |
| * Generate concurrent accesses, expecting no reports, ensuring KCSAN |
| * treats builtin atomics as actually atomic. |
| */ |
| __atomic_load_n(&test_var, __ATOMIC_RELAXED); |
| } |
| |
| static noinline void test_kernel_xor_1bit(void) |
| { |
| /* Do not report data races between the read-writes. */ |
| kcsan_nestable_atomic_begin(); |
| test_var ^= 0x10000; |
| kcsan_nestable_atomic_end(); |
| } |
| |
| #define TEST_KERNEL_LOCKED(name, acquire, release) \ |
| static noinline void test_kernel_##name(void) \ |
| { \ |
| long *flag = &test_struct.val[0]; \ |
| long v = 0; \ |
| if (!(acquire)) \ |
| return; \ |
| while (v++ < 100) { \ |
| test_var++; \ |
| barrier(); \ |
| } \ |
| release; \ |
| test_delay(10); \ |
| } |
| |
| TEST_KERNEL_LOCKED(with_memorder, |
| cmpxchg_acquire(flag, 0, 1) == 0, |
| smp_store_release(flag, 0)); |
| TEST_KERNEL_LOCKED(wrong_memorder, |
| cmpxchg_relaxed(flag, 0, 1) == 0, |
| WRITE_ONCE(*flag, 0)); |
| TEST_KERNEL_LOCKED(atomic_builtin_with_memorder, |
| __atomic_compare_exchange_n(flag, &v, 1, 0, __ATOMIC_ACQUIRE, __ATOMIC_RELAXED), |
| __atomic_store_n(flag, 0, __ATOMIC_RELEASE)); |
| TEST_KERNEL_LOCKED(atomic_builtin_wrong_memorder, |
| __atomic_compare_exchange_n(flag, &v, 1, 0, __ATOMIC_RELAXED, __ATOMIC_RELAXED), |
| __atomic_store_n(flag, 0, __ATOMIC_RELAXED)); |
| |
| /* ===== Test cases ===== */ |
| |
| /* |
| * Tests that various barriers have the expected effect on internal state. Not |
| * exhaustive on atomic_t operations. Unlike the selftest, also checks for |
| * too-strict barrier instrumentation; these can be tolerated, because it does |
| * not cause false positives, but at least we should be aware of such cases. |
| */ |
| static void test_barrier_nothreads(struct kunit *test) |
| { |
| #ifdef CONFIG_KCSAN_WEAK_MEMORY |
| struct kcsan_scoped_access *reorder_access = ¤t->kcsan_ctx.reorder_access; |
| #else |
| struct kcsan_scoped_access *reorder_access = NULL; |
| #endif |
| arch_spinlock_t arch_spinlock = __ARCH_SPIN_LOCK_UNLOCKED; |
| atomic_t dummy; |
| |
| KCSAN_TEST_REQUIRES(test, reorder_access != NULL); |
| KCSAN_TEST_REQUIRES(test, IS_ENABLED(CONFIG_SMP)); |
| |
| #define __KCSAN_EXPECT_BARRIER(access_type, barrier, order_before, name) \ |
| do { \ |
| reorder_access->type = (access_type) | KCSAN_ACCESS_SCOPED; \ |
| reorder_access->size = sizeof(test_var); \ |
| barrier; \ |
| KUNIT_EXPECT_EQ_MSG(test, reorder_access->size, \ |
| order_before ? 0 : sizeof(test_var), \ |
| "improperly instrumented type=(" #access_type "): " name); \ |
| } while (0) |
| #define KCSAN_EXPECT_READ_BARRIER(b, o) __KCSAN_EXPECT_BARRIER(0, b, o, #b) |
| #define KCSAN_EXPECT_WRITE_BARRIER(b, o) __KCSAN_EXPECT_BARRIER(KCSAN_ACCESS_WRITE, b, o, #b) |
| #define KCSAN_EXPECT_RW_BARRIER(b, o) __KCSAN_EXPECT_BARRIER(KCSAN_ACCESS_COMPOUND | KCSAN_ACCESS_WRITE, b, o, #b) |
| |
| /* |
| * Lockdep initialization can strengthen certain locking operations due |
| * to calling into instrumented files; "warm up" our locks. |
| */ |
| spin_lock(&test_spinlock); |
| spin_unlock(&test_spinlock); |
| mutex_lock(&test_mutex); |
| mutex_unlock(&test_mutex); |
| |
| /* Force creating a valid entry in reorder_access first. */ |
| test_var = 0; |
| while (test_var++ < 1000000 && reorder_access->size != sizeof(test_var)) |
| __kcsan_check_read(&test_var, sizeof(test_var)); |
| KUNIT_ASSERT_EQ(test, reorder_access->size, sizeof(test_var)); |
| |
| kcsan_nestable_atomic_begin(); /* No watchpoints in called functions. */ |
| |
| KCSAN_EXPECT_READ_BARRIER(mb(), true); |
| KCSAN_EXPECT_READ_BARRIER(wmb(), false); |
| KCSAN_EXPECT_READ_BARRIER(rmb(), true); |
| KCSAN_EXPECT_READ_BARRIER(smp_mb(), true); |
| KCSAN_EXPECT_READ_BARRIER(smp_wmb(), false); |
| KCSAN_EXPECT_READ_BARRIER(smp_rmb(), true); |
| KCSAN_EXPECT_READ_BARRIER(dma_wmb(), false); |
| KCSAN_EXPECT_READ_BARRIER(dma_rmb(), true); |
| KCSAN_EXPECT_READ_BARRIER(smp_mb__before_atomic(), true); |
| KCSAN_EXPECT_READ_BARRIER(smp_mb__after_atomic(), true); |
| KCSAN_EXPECT_READ_BARRIER(smp_mb__after_spinlock(), true); |
| KCSAN_EXPECT_READ_BARRIER(smp_store_mb(test_var, 0), true); |
| KCSAN_EXPECT_READ_BARRIER(smp_load_acquire(&test_var), false); |
| KCSAN_EXPECT_READ_BARRIER(smp_store_release(&test_var, 0), true); |
| KCSAN_EXPECT_READ_BARRIER(xchg(&test_var, 0), true); |
| KCSAN_EXPECT_READ_BARRIER(xchg_release(&test_var, 0), true); |
| KCSAN_EXPECT_READ_BARRIER(xchg_relaxed(&test_var, 0), false); |
| KCSAN_EXPECT_READ_BARRIER(cmpxchg(&test_var, 0, 0), true); |
| KCSAN_EXPECT_READ_BARRIER(cmpxchg_release(&test_var, 0, 0), true); |
| KCSAN_EXPECT_READ_BARRIER(cmpxchg_relaxed(&test_var, 0, 0), false); |
| KCSAN_EXPECT_READ_BARRIER(atomic_read(&dummy), false); |
| KCSAN_EXPECT_READ_BARRIER(atomic_read_acquire(&dummy), false); |
| KCSAN_EXPECT_READ_BARRIER(atomic_set(&dummy, 0), false); |
| KCSAN_EXPECT_READ_BARRIER(atomic_set_release(&dummy, 0), true); |
| KCSAN_EXPECT_READ_BARRIER(atomic_add(1, &dummy), false); |
| KCSAN_EXPECT_READ_BARRIER(atomic_add_return(1, &dummy), true); |
| KCSAN_EXPECT_READ_BARRIER(atomic_add_return_acquire(1, &dummy), false); |
| KCSAN_EXPECT_READ_BARRIER(atomic_add_return_release(1, &dummy), true); |
| KCSAN_EXPECT_READ_BARRIER(atomic_add_return_relaxed(1, &dummy), false); |
| KCSAN_EXPECT_READ_BARRIER(atomic_fetch_add(1, &dummy), true); |
| KCSAN_EXPECT_READ_BARRIER(atomic_fetch_add_acquire(1, &dummy), false); |
| KCSAN_EXPECT_READ_BARRIER(atomic_fetch_add_release(1, &dummy), true); |
| KCSAN_EXPECT_READ_BARRIER(atomic_fetch_add_relaxed(1, &dummy), false); |
| KCSAN_EXPECT_READ_BARRIER(test_and_set_bit(0, &test_var), true); |
| KCSAN_EXPECT_READ_BARRIER(test_and_clear_bit(0, &test_var), true); |
| KCSAN_EXPECT_READ_BARRIER(test_and_change_bit(0, &test_var), true); |
| KCSAN_EXPECT_READ_BARRIER(clear_bit_unlock(0, &test_var), true); |
| KCSAN_EXPECT_READ_BARRIER(__clear_bit_unlock(0, &test_var), true); |
| KCSAN_EXPECT_READ_BARRIER(arch_spin_lock(&arch_spinlock), false); |
| KCSAN_EXPECT_READ_BARRIER(arch_spin_unlock(&arch_spinlock), true); |
| KCSAN_EXPECT_READ_BARRIER(spin_lock(&test_spinlock), false); |
| KCSAN_EXPECT_READ_BARRIER(spin_unlock(&test_spinlock), true); |
| KCSAN_EXPECT_READ_BARRIER(mutex_lock(&test_mutex), false); |
| KCSAN_EXPECT_READ_BARRIER(mutex_unlock(&test_mutex), true); |
| |
| KCSAN_EXPECT_WRITE_BARRIER(mb(), true); |
| KCSAN_EXPECT_WRITE_BARRIER(wmb(), true); |
| KCSAN_EXPECT_WRITE_BARRIER(rmb(), false); |
| KCSAN_EXPECT_WRITE_BARRIER(smp_mb(), true); |
| KCSAN_EXPECT_WRITE_BARRIER(smp_wmb(), true); |
| KCSAN_EXPECT_WRITE_BARRIER(smp_rmb(), false); |
| KCSAN_EXPECT_WRITE_BARRIER(dma_wmb(), true); |
| KCSAN_EXPECT_WRITE_BARRIER(dma_rmb(), false); |
| KCSAN_EXPECT_WRITE_BARRIER(smp_mb__before_atomic(), true); |
| KCSAN_EXPECT_WRITE_BARRIER(smp_mb__after_atomic(), true); |
| KCSAN_EXPECT_WRITE_BARRIER(smp_mb__after_spinlock(), true); |
| KCSAN_EXPECT_WRITE_BARRIER(smp_store_mb(test_var, 0), true); |
| KCSAN_EXPECT_WRITE_BARRIER(smp_load_acquire(&test_var), false); |
| KCSAN_EXPECT_WRITE_BARRIER(smp_store_release(&test_var, 0), true); |
| KCSAN_EXPECT_WRITE_BARRIER(xchg(&test_var, 0), true); |
| KCSAN_EXPECT_WRITE_BARRIER(xchg_release(&test_var, 0), true); |
| KCSAN_EXPECT_WRITE_BARRIER(xchg_relaxed(&test_var, 0), false); |
| KCSAN_EXPECT_WRITE_BARRIER(cmpxchg(&test_var, 0, 0), true); |
| KCSAN_EXPECT_WRITE_BARRIER(cmpxchg_release(&test_var, 0, 0), true); |
| KCSAN_EXPECT_WRITE_BARRIER(cmpxchg_relaxed(&test_var, 0, 0), false); |
| KCSAN_EXPECT_WRITE_BARRIER(atomic_read(&dummy), false); |
| KCSAN_EXPECT_WRITE_BARRIER(atomic_read_acquire(&dummy), false); |
| KCSAN_EXPECT_WRITE_BARRIER(atomic_set(&dummy, 0), false); |
| KCSAN_EXPECT_WRITE_BARRIER(atomic_set_release(&dummy, 0), true); |
| KCSAN_EXPECT_WRITE_BARRIER(atomic_add(1, &dummy), false); |
| KCSAN_EXPECT_WRITE_BARRIER(atomic_add_return(1, &dummy), true); |
| KCSAN_EXPECT_WRITE_BARRIER(atomic_add_return_acquire(1, &dummy), false); |
| KCSAN_EXPECT_WRITE_BARRIER(atomic_add_return_release(1, &dummy), true); |
| KCSAN_EXPECT_WRITE_BARRIER(atomic_add_return_relaxed(1, &dummy), false); |
| KCSAN_EXPECT_WRITE_BARRIER(atomic_fetch_add(1, &dummy), true); |
| KCSAN_EXPECT_WRITE_BARRIER(atomic_fetch_add_acquire(1, &dummy), false); |
| KCSAN_EXPECT_WRITE_BARRIER(atomic_fetch_add_release(1, &dummy), true); |
| KCSAN_EXPECT_WRITE_BARRIER(atomic_fetch_add_relaxed(1, &dummy), false); |
| KCSAN_EXPECT_WRITE_BARRIER(test_and_set_bit(0, &test_var), true); |
| KCSAN_EXPECT_WRITE_BARRIER(test_and_clear_bit(0, &test_var), true); |
| KCSAN_EXPECT_WRITE_BARRIER(test_and_change_bit(0, &test_var), true); |
| KCSAN_EXPECT_WRITE_BARRIER(clear_bit_unlock(0, &test_var), true); |
| KCSAN_EXPECT_WRITE_BARRIER(__clear_bit_unlock(0, &test_var), true); |
| KCSAN_EXPECT_WRITE_BARRIER(arch_spin_lock(&arch_spinlock), false); |
| KCSAN_EXPECT_WRITE_BARRIER(arch_spin_unlock(&arch_spinlock), true); |
| KCSAN_EXPECT_WRITE_BARRIER(spin_lock(&test_spinlock), false); |
| KCSAN_EXPECT_WRITE_BARRIER(spin_unlock(&test_spinlock), true); |
| KCSAN_EXPECT_WRITE_BARRIER(mutex_lock(&test_mutex), false); |
| KCSAN_EXPECT_WRITE_BARRIER(mutex_unlock(&test_mutex), true); |
| |
| KCSAN_EXPECT_RW_BARRIER(mb(), true); |
| KCSAN_EXPECT_RW_BARRIER(wmb(), true); |
| KCSAN_EXPECT_RW_BARRIER(rmb(), true); |
| KCSAN_EXPECT_RW_BARRIER(smp_mb(), true); |
| KCSAN_EXPECT_RW_BARRIER(smp_wmb(), true); |
| KCSAN_EXPECT_RW_BARRIER(smp_rmb(), true); |
| KCSAN_EXPECT_RW_BARRIER(dma_wmb(), true); |
| KCSAN_EXPECT_RW_BARRIER(dma_rmb(), true); |
| KCSAN_EXPECT_RW_BARRIER(smp_mb__before_atomic(), true); |
| KCSAN_EXPECT_RW_BARRIER(smp_mb__after_atomic(), true); |
| KCSAN_EXPECT_RW_BARRIER(smp_mb__after_spinlock(), true); |
| KCSAN_EXPECT_RW_BARRIER(smp_store_mb(test_var, 0), true); |
| KCSAN_EXPECT_RW_BARRIER(smp_load_acquire(&test_var), false); |
| KCSAN_EXPECT_RW_BARRIER(smp_store_release(&test_var, 0), true); |
| KCSAN_EXPECT_RW_BARRIER(xchg(&test_var, 0), true); |
| KCSAN_EXPECT_RW_BARRIER(xchg_release(&test_var, 0), true); |
| KCSAN_EXPECT_RW_BARRIER(xchg_relaxed(&test_var, 0), false); |
| KCSAN_EXPECT_RW_BARRIER(cmpxchg(&test_var, 0, 0), true); |
| KCSAN_EXPECT_RW_BARRIER(cmpxchg_release(&test_var, 0, 0), true); |
| KCSAN_EXPECT_RW_BARRIER(cmpxchg_relaxed(&test_var, 0, 0), false); |
| KCSAN_EXPECT_RW_BARRIER(atomic_read(&dummy), false); |
| KCSAN_EXPECT_RW_BARRIER(atomic_read_acquire(&dummy), false); |
| KCSAN_EXPECT_RW_BARRIER(atomic_set(&dummy, 0), false); |
| KCSAN_EXPECT_RW_BARRIER(atomic_set_release(&dummy, 0), true); |
| KCSAN_EXPECT_RW_BARRIER(atomic_add(1, &dummy), false); |
| KCSAN_EXPECT_RW_BARRIER(atomic_add_return(1, &dummy), true); |
| KCSAN_EXPECT_RW_BARRIER(atomic_add_return_acquire(1, &dummy), false); |
| KCSAN_EXPECT_RW_BARRIER(atomic_add_return_release(1, &dummy), true); |
| KCSAN_EXPECT_RW_BARRIER(atomic_add_return_relaxed(1, &dummy), false); |
| KCSAN_EXPECT_RW_BARRIER(atomic_fetch_add(1, &dummy), true); |
| KCSAN_EXPECT_RW_BARRIER(atomic_fetch_add_acquire(1, &dummy), false); |
| KCSAN_EXPECT_RW_BARRIER(atomic_fetch_add_release(1, &dummy), true); |
| KCSAN_EXPECT_RW_BARRIER(atomic_fetch_add_relaxed(1, &dummy), false); |
| KCSAN_EXPECT_RW_BARRIER(test_and_set_bit(0, &test_var), true); |
| KCSAN_EXPECT_RW_BARRIER(test_and_clear_bit(0, &test_var), true); |
| KCSAN_EXPECT_RW_BARRIER(test_and_change_bit(0, &test_var), true); |
| KCSAN_EXPECT_RW_BARRIER(clear_bit_unlock(0, &test_var), true); |
| KCSAN_EXPECT_RW_BARRIER(__clear_bit_unlock(0, &test_var), true); |
| KCSAN_EXPECT_RW_BARRIER(arch_spin_lock(&arch_spinlock), false); |
| KCSAN_EXPECT_RW_BARRIER(arch_spin_unlock(&arch_spinlock), true); |
| KCSAN_EXPECT_RW_BARRIER(spin_lock(&test_spinlock), false); |
| KCSAN_EXPECT_RW_BARRIER(spin_unlock(&test_spinlock), true); |
| KCSAN_EXPECT_RW_BARRIER(mutex_lock(&test_mutex), false); |
| KCSAN_EXPECT_RW_BARRIER(mutex_unlock(&test_mutex), true); |
| |
| #ifdef clear_bit_unlock_is_negative_byte |
| KCSAN_EXPECT_READ_BARRIER(clear_bit_unlock_is_negative_byte(0, &test_var), true); |
| KCSAN_EXPECT_WRITE_BARRIER(clear_bit_unlock_is_negative_byte(0, &test_var), true); |
| KCSAN_EXPECT_RW_BARRIER(clear_bit_unlock_is_negative_byte(0, &test_var), true); |
| #endif |
| kcsan_nestable_atomic_end(); |
| } |
| |
| /* Simple test with normal data race. */ |
| __no_kcsan |
| static void test_basic(struct kunit *test) |
| { |
| struct expect_report expect = { |
| .access = { |
| { test_kernel_write, &test_var, sizeof(test_var), KCSAN_ACCESS_WRITE }, |
| { test_kernel_read, &test_var, sizeof(test_var), 0 }, |
| }, |
| }; |
| struct expect_report never = { |
| .access = { |
| { test_kernel_read, &test_var, sizeof(test_var), 0 }, |
| { test_kernel_read, &test_var, sizeof(test_var), 0 }, |
| }, |
| }; |
| bool match_expect = false; |
| bool match_never = false; |
| |
| begin_test_checks(test_kernel_write, test_kernel_read); |
| do { |
| match_expect |= report_matches(&expect); |
| match_never = report_matches(&never); |
| } while (!end_test_checks(match_never)); |
| KUNIT_EXPECT_TRUE(test, match_expect); |
| KUNIT_EXPECT_FALSE(test, match_never); |
| } |
| |
| /* |
| * Stress KCSAN with lots of concurrent races on different addresses until |
| * timeout. |
| */ |
| __no_kcsan |
| static void test_concurrent_races(struct kunit *test) |
| { |
| struct expect_report expect = { |
| .access = { |
| /* NULL will match any address. */ |
| { test_kernel_rmw_array, NULL, 0, __KCSAN_ACCESS_RW(KCSAN_ACCESS_WRITE) }, |
| { test_kernel_rmw_array, NULL, 0, __KCSAN_ACCESS_RW(0) }, |
| }, |
| }; |
| struct expect_report never = { |
| .access = { |
| { test_kernel_rmw_array, NULL, 0, 0 }, |
| { test_kernel_rmw_array, NULL, 0, 0 }, |
| }, |
| }; |
| bool match_expect = false; |
| bool match_never = false; |
| |
| begin_test_checks(test_kernel_rmw_array, test_kernel_rmw_array); |
| do { |
| match_expect |= report_matches(&expect); |
| match_never |= report_matches(&never); |
| } while (!end_test_checks(false)); |
| KUNIT_EXPECT_TRUE(test, match_expect); /* Sanity check matches exist. */ |
| KUNIT_EXPECT_FALSE(test, match_never); |
| } |
| |
| /* Test the KCSAN_REPORT_VALUE_CHANGE_ONLY option. */ |
| __no_kcsan |
| static void test_novalue_change(struct kunit *test) |
| { |
| struct expect_report expect_rw = { |
| .access = { |
| { test_kernel_write_nochange, &test_var, sizeof(test_var), KCSAN_ACCESS_WRITE }, |
| { test_kernel_read, &test_var, sizeof(test_var), 0 }, |
| }, |
| }; |
| struct expect_report expect_ww = { |
| .access = { |
| { test_kernel_write_nochange, &test_var, sizeof(test_var), KCSAN_ACCESS_WRITE }, |
| { test_kernel_write_nochange, &test_var, sizeof(test_var), KCSAN_ACCESS_WRITE }, |
| }, |
| }; |
| bool match_expect = false; |
| |
| test_kernel_write_nochange(); /* Reset value. */ |
| begin_test_checks(test_kernel_write_nochange, test_kernel_read); |
| do { |
| match_expect = report_matches(&expect_rw) || report_matches(&expect_ww); |
| } while (!end_test_checks(match_expect)); |
| if (IS_ENABLED(CONFIG_KCSAN_REPORT_VALUE_CHANGE_ONLY)) |
| KUNIT_EXPECT_FALSE(test, match_expect); |
| else |
| KUNIT_EXPECT_TRUE(test, match_expect); |
| } |
| |
| /* |
| * Test that the rules where the KCSAN_REPORT_VALUE_CHANGE_ONLY option should |
| * never apply work. |
| */ |
| __no_kcsan |
| static void test_novalue_change_exception(struct kunit *test) |
| { |
| struct expect_report expect_rw = { |
| .access = { |
| { test_kernel_write_nochange_rcu, &test_var, sizeof(test_var), KCSAN_ACCESS_WRITE }, |
| { test_kernel_read, &test_var, sizeof(test_var), 0 }, |
| }, |
| }; |
| struct expect_report expect_ww = { |
| .access = { |
| { test_kernel_write_nochange_rcu, &test_var, sizeof(test_var), KCSAN_ACCESS_WRITE }, |
| { test_kernel_write_nochange_rcu, &test_var, sizeof(test_var), KCSAN_ACCESS_WRITE }, |
| }, |
| }; |
| bool match_expect = false; |
| |
| test_kernel_write_nochange_rcu(); /* Reset value. */ |
| begin_test_checks(test_kernel_write_nochange_rcu, test_kernel_read); |
| do { |
| match_expect = report_matches(&expect_rw) || report_matches(&expect_ww); |
| } while (!end_test_checks(match_expect)); |
| KUNIT_EXPECT_TRUE(test, match_expect); |
| } |
| |
| /* Test that data races of unknown origin are reported. */ |
| __no_kcsan |
| static void test_unknown_origin(struct kunit *test) |
| { |
| struct expect_report expect = { |
| .access = { |
| { test_kernel_read, &test_var, sizeof(test_var), 0 }, |
| { NULL }, |
| }, |
| }; |
| bool match_expect = false; |
| |
| begin_test_checks(test_kernel_write_uninstrumented, test_kernel_read); |
| do { |
| match_expect = report_matches(&expect); |
| } while (!end_test_checks(match_expect)); |
| if (IS_ENABLED(CONFIG_KCSAN_REPORT_RACE_UNKNOWN_ORIGIN)) |
| KUNIT_EXPECT_TRUE(test, match_expect); |
| else |
| KUNIT_EXPECT_FALSE(test, match_expect); |
| } |
| |
| /* Test KCSAN_ASSUME_PLAIN_WRITES_ATOMIC if it is selected. */ |
| __no_kcsan |
| static void test_write_write_assume_atomic(struct kunit *test) |
| { |
| struct expect_report expect = { |
| .access = { |
| { test_kernel_write, &test_var, sizeof(test_var), KCSAN_ACCESS_WRITE }, |
| { test_kernel_write, &test_var, sizeof(test_var), KCSAN_ACCESS_WRITE }, |
| }, |
| }; |
| bool match_expect = false; |
| |
| begin_test_checks(test_kernel_write, test_kernel_write); |
| do { |
| sink_value(READ_ONCE(test_var)); /* induce value-change */ |
| match_expect = report_matches(&expect); |
| } while (!end_test_checks(match_expect)); |
| if (IS_ENABLED(CONFIG_KCSAN_ASSUME_PLAIN_WRITES_ATOMIC)) |
| KUNIT_EXPECT_FALSE(test, match_expect); |
| else |
| KUNIT_EXPECT_TRUE(test, match_expect); |
| } |
| |
| /* |
| * Test that data races with writes larger than word-size are always reported, |
| * even if KCSAN_ASSUME_PLAIN_WRITES_ATOMIC is selected. |
| */ |
| __no_kcsan |
| static void test_write_write_struct(struct kunit *test) |
| { |
| struct expect_report expect = { |
| .access = { |
| { test_kernel_write_struct, &test_struct, sizeof(test_struct), KCSAN_ACCESS_WRITE }, |
| { test_kernel_write_struct, &test_struct, sizeof(test_struct), KCSAN_ACCESS_WRITE }, |
| }, |
| }; |
| bool match_expect = false; |
| |
| begin_test_checks(test_kernel_write_struct, test_kernel_write_struct); |
| do { |
| match_expect = report_matches(&expect); |
| } while (!end_test_checks(match_expect)); |
| KUNIT_EXPECT_TRUE(test, match_expect); |
| } |
| |
| /* |
| * Test that data races where only one write is larger than word-size are always |
| * reported, even if KCSAN_ASSUME_PLAIN_WRITES_ATOMIC is selected. |
| */ |
| __no_kcsan |
| static void test_write_write_struct_part(struct kunit *test) |
| { |
| struct expect_report expect = { |
| .access = { |
| { test_kernel_write_struct, &test_struct, sizeof(test_struct), KCSAN_ACCESS_WRITE }, |
| { test_kernel_write_struct_part, &test_struct.val[3], sizeof(test_struct.val[3]), KCSAN_ACCESS_WRITE }, |
| }, |
| }; |
| bool match_expect = false; |
| |
| begin_test_checks(test_kernel_write_struct, test_kernel_write_struct_part); |
| do { |
| match_expect = report_matches(&expect); |
| } while (!end_test_checks(match_expect)); |
| KUNIT_EXPECT_TRUE(test, match_expect); |
| } |
| |
| /* Test that races with atomic accesses never result in reports. */ |
| __no_kcsan |
| static void test_read_atomic_write_atomic(struct kunit *test) |
| { |
| bool match_never = false; |
| |
| begin_test_checks(test_kernel_read_atomic, test_kernel_write_atomic); |
| do { |
| match_never = report_available(); |
| } while (!end_test_checks(match_never)); |
| KUNIT_EXPECT_FALSE(test, match_never); |
| } |
| |
| /* Test that a race with an atomic and plain access result in reports. */ |
| __no_kcsan |
| static void test_read_plain_atomic_write(struct kunit *test) |
| { |
| struct expect_report expect = { |
| .access = { |
| { test_kernel_read, &test_var, sizeof(test_var), 0 }, |
| { test_kernel_write_atomic, &test_var, sizeof(test_var), KCSAN_ACCESS_WRITE | KCSAN_ACCESS_ATOMIC }, |
| }, |
| }; |
| bool match_expect = false; |
| |
| KCSAN_TEST_REQUIRES(test, !IS_ENABLED(CONFIG_KCSAN_IGNORE_ATOMICS)); |
| |
| begin_test_checks(test_kernel_read, test_kernel_write_atomic); |
| do { |
| match_expect = report_matches(&expect); |
| } while (!end_test_checks(match_expect)); |
| 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) |
| { |
| 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; |
| |
| KCSAN_TEST_REQUIRES(test, !IS_ENABLED(CONFIG_KCSAN_IGNORE_ATOMICS)); |
| |
| 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) |
| { |
| struct expect_report expect = { |
| .access = { |
| { test_kernel_write_struct, &test_struct, sizeof(test_struct), KCSAN_ACCESS_WRITE }, |
| { test_kernel_write_struct, &test_struct, sizeof(test_struct), KCSAN_ACCESS_WRITE }, |
| }, |
| }; |
| struct expect_report never = { |
| .access = { |
| { test_kernel_write_struct, &test_struct, sizeof(test_struct), KCSAN_ACCESS_WRITE }, |
| { test_kernel_read_struct_zero_size, &test_struct.val[3], 0, 0 }, |
| }, |
| }; |
| bool match_expect = false; |
| bool match_never = false; |
| |
| begin_test_checks(test_kernel_write_struct, test_kernel_read_struct_zero_size); |
| do { |
| match_expect |= report_matches(&expect); |
| match_never = report_matches(&never); |
| } while (!end_test_checks(match_never)); |
| KUNIT_EXPECT_TRUE(test, match_expect); /* Sanity check. */ |
| KUNIT_EXPECT_FALSE(test, match_never); |
| } |
| |
| /* Test the data_race() macro. */ |
| __no_kcsan |
| static void test_data_race(struct kunit *test) |
| { |
| bool match_never = false; |
| |
| begin_test_checks(test_kernel_data_race, test_kernel_data_race); |
| do { |
| match_never = report_available(); |
| } while (!end_test_checks(match_never)); |
| KUNIT_EXPECT_FALSE(test, match_never); |
| } |
| |
| __no_kcsan |
| static void test_assert_exclusive_writer(struct kunit *test) |
| { |
| struct expect_report expect = { |
| .access = { |
| { test_kernel_assert_writer, &test_var, sizeof(test_var), KCSAN_ACCESS_ASSERT }, |
| { test_kernel_write_nochange, &test_var, sizeof(test_var), KCSAN_ACCESS_WRITE }, |
| }, |
| }; |
| bool match_expect = false; |
| |
| begin_test_checks(test_kernel_assert_writer, test_kernel_write_nochange); |
| do { |
| match_expect = report_matches(&expect); |
| } while (!end_test_checks(match_expect)); |
| KUNIT_EXPECT_TRUE(test, match_expect); |
| } |
| |
| __no_kcsan |
| static void test_assert_exclusive_access(struct kunit *test) |
| { |
| struct expect_report expect = { |
| .access = { |
| { test_kernel_assert_access, &test_var, sizeof(test_var), KCSAN_ACCESS_ASSERT | KCSAN_ACCESS_WRITE }, |
| { test_kernel_read, &test_var, sizeof(test_var), 0 }, |
| }, |
| }; |
| bool match_expect = false; |
| |
| begin_test_checks(test_kernel_assert_access, test_kernel_read); |
| do { |
| match_expect = report_matches(&expect); |
| } while (!end_test_checks(match_expect)); |
| KUNIT_EXPECT_TRUE(test, match_expect); |
| } |
| |
| __no_kcsan |
| static void test_assert_exclusive_access_writer(struct kunit *test) |
| { |
| struct expect_report expect_access_writer = { |
| .access = { |
| { test_kernel_assert_access, &test_var, sizeof(test_var), KCSAN_ACCESS_ASSERT | KCSAN_ACCESS_WRITE }, |
| { test_kernel_assert_writer, &test_var, sizeof(test_var), KCSAN_ACCESS_ASSERT }, |
| }, |
| }; |
| struct expect_report expect_access_access = { |
| .access = { |
| { test_kernel_assert_access, &test_var, sizeof(test_var), KCSAN_ACCESS_ASSERT | KCSAN_ACCESS_WRITE }, |
| { test_kernel_assert_access, &test_var, sizeof(test_var), KCSAN_ACCESS_ASSERT | KCSAN_ACCESS_WRITE }, |
| }, |
| }; |
| struct expect_report never = { |
| .access = { |
| { test_kernel_assert_writer, &test_var, sizeof(test_var), KCSAN_ACCESS_ASSERT }, |
| { test_kernel_assert_writer, &test_var, sizeof(test_var), KCSAN_ACCESS_ASSERT }, |
| }, |
| }; |
| bool match_expect_access_writer = false; |
| bool match_expect_access_access = false; |
| bool match_never = false; |
| |
| begin_test_checks(test_kernel_assert_access, test_kernel_assert_writer); |
| do { |
| match_expect_access_writer |= report_matches(&expect_access_writer); |
| match_expect_access_access |= report_matches(&expect_access_access); |
| match_never |= report_matches(&never); |
| } while (!end_test_checks(match_never)); |
| KUNIT_EXPECT_TRUE(test, match_expect_access_writer); |
| KUNIT_EXPECT_TRUE(test, match_expect_access_access); |
| KUNIT_EXPECT_FALSE(test, match_never); |
| } |
| |
| __no_kcsan |
| static void test_assert_exclusive_bits_change(struct kunit *test) |
| { |
| struct expect_report expect = { |
| .access = { |
| { test_kernel_assert_bits_change, &test_var, sizeof(test_var), KCSAN_ACCESS_ASSERT }, |
| { test_kernel_change_bits, &test_var, sizeof(test_var), |
| KCSAN_ACCESS_WRITE | (IS_ENABLED(CONFIG_KCSAN_IGNORE_ATOMICS) ? 0 : KCSAN_ACCESS_ATOMIC) }, |
| }, |
| }; |
| bool match_expect = false; |
| |
| begin_test_checks(test_kernel_assert_bits_change, test_kernel_change_bits); |
| do { |
| match_expect = report_matches(&expect); |
| } while (!end_test_checks(match_expect)); |
| KUNIT_EXPECT_TRUE(test, match_expect); |
| } |
| |
| __no_kcsan |
| static void test_assert_exclusive_bits_nochange(struct kunit *test) |
| { |
| bool match_never = false; |
| |
| begin_test_checks(test_kernel_assert_bits_nochange, test_kernel_change_bits); |
| do { |
| match_never = report_available(); |
| } while (!end_test_checks(match_never)); |
| KUNIT_EXPECT_FALSE(test, match_never); |
| } |
| |
| __no_kcsan |
| static void test_assert_exclusive_writer_scoped(struct kunit *test) |
| { |
| struct expect_report expect_start = { |
| .access = { |
| { test_kernel_assert_writer_scoped, &test_var, sizeof(test_var), KCSAN_ACCESS_ASSERT | KCSAN_ACCESS_SCOPED }, |
| { test_kernel_write_nochange, &test_var, sizeof(test_var), KCSAN_ACCESS_WRITE }, |
| }, |
| }; |
| struct expect_report expect_inscope = { |
| .access = { |
| { test_enter_scope, &test_var, sizeof(test_var), KCSAN_ACCESS_ASSERT | KCSAN_ACCESS_SCOPED }, |
| { test_kernel_write_nochange, &test_var, sizeof(test_var), KCSAN_ACCESS_WRITE }, |
| }, |
| }; |
| bool match_expect_start = false; |
| bool match_expect_inscope = false; |
| |
| begin_test_checks(test_kernel_assert_writer_scoped, test_kernel_write_nochange); |
| do { |
| match_expect_start |= report_matches(&expect_start); |
| match_expect_inscope |= report_matches(&expect_inscope); |
| } while (!end_test_checks(match_expect_inscope)); |
| KUNIT_EXPECT_TRUE(test, match_expect_start); |
| KUNIT_EXPECT_FALSE(test, match_expect_inscope); |
| } |
| |
| __no_kcsan |
| static void test_assert_exclusive_access_scoped(struct kunit *test) |
| { |
| struct expect_report expect_start1 = { |
| .access = { |
| { test_kernel_assert_access_scoped, &test_var, sizeof(test_var), KCSAN_ACCESS_ASSERT | KCSAN_ACCESS_WRITE | KCSAN_ACCESS_SCOPED }, |
| { test_kernel_read, &test_var, sizeof(test_var), 0 }, |
| }, |
| }; |
| struct expect_report expect_start2 = { |
| .access = { expect_start1.access[0], expect_start1.access[0] }, |
| }; |
| struct expect_report expect_inscope = { |
| .access = { |
| { test_enter_scope, &test_var, sizeof(test_var), KCSAN_ACCESS_ASSERT | KCSAN_ACCESS_WRITE | KCSAN_ACCESS_SCOPED }, |
| { test_kernel_read, &test_var, sizeof(test_var), 0 }, |
| }, |
| }; |
| bool match_expect_start = false; |
| bool match_expect_inscope = false; |
| |
| begin_test_checks(test_kernel_assert_access_scoped, test_kernel_read); |
| end_time += msecs_to_jiffies(1000); /* This test requires a bit more time. */ |
| do { |
| match_expect_start |= report_matches(&expect_start1) || report_matches(&expect_start2); |
| match_expect_inscope |= report_matches(&expect_inscope); |
| } while (!end_test_checks(match_expect_inscope)); |
| KUNIT_EXPECT_TRUE(test, match_expect_start); |
| KUNIT_EXPECT_FALSE(test, match_expect_inscope); |
| } |
| |
| /* |
| * jiffies is special (declared to be volatile) and its accesses are typically |
| * not marked; this test ensures that the compiler nor KCSAN gets confused about |
| * jiffies's declaration on different architectures. |
| */ |
| __no_kcsan |
| static void test_jiffies_noreport(struct kunit *test) |
| { |
| bool match_never = false; |
| |
| begin_test_checks(test_kernel_jiffies_reader, test_kernel_jiffies_reader); |
| do { |
| match_never = report_available(); |
| } while (!end_test_checks(match_never)); |
| KUNIT_EXPECT_FALSE(test, match_never); |
| } |
| |
| /* Test that racing accesses in seqlock critical sections are not reported. */ |
| __no_kcsan |
| static void test_seqlock_noreport(struct kunit *test) |
| { |
| bool match_never = false; |
| |
| begin_test_checks(test_kernel_seqlock_reader, test_kernel_seqlock_writer); |
| do { |
| match_never = report_available(); |
| } while (!end_test_checks(match_never)); |
| KUNIT_EXPECT_FALSE(test, match_never); |
| } |
| |
| /* |
| * Test atomic builtins work and required instrumentation functions exist. We |
| * also test that KCSAN understands they're atomic by racing with them via |
| * test_kernel_atomic_builtins(), and expect no reports. |
| * |
| * The atomic builtins _SHOULD NOT_ be used in normal kernel code! |
| */ |
| static void test_atomic_builtins(struct kunit *test) |
| { |
| bool match_never = false; |
| |
| begin_test_checks(test_kernel_atomic_builtins, test_kernel_atomic_builtins); |
| do { |
| long tmp; |
| |
| kcsan_enable_current(); |
| |
| __atomic_store_n(&test_var, 42L, __ATOMIC_RELAXED); |
| KUNIT_EXPECT_EQ(test, 42L, __atomic_load_n(&test_var, __ATOMIC_RELAXED)); |
| |
| KUNIT_EXPECT_EQ(test, 42L, __atomic_exchange_n(&test_var, 20, __ATOMIC_RELAXED)); |
| KUNIT_EXPECT_EQ(test, 20L, test_var); |
| |
| tmp = 20L; |
| KUNIT_EXPECT_TRUE(test, __atomic_compare_exchange_n(&test_var, &tmp, 30L, |
| 0, __ATOMIC_RELAXED, |
| __ATOMIC_RELAXED)); |
| KUNIT_EXPECT_EQ(test, tmp, 20L); |
| KUNIT_EXPECT_EQ(test, test_var, 30L); |
| KUNIT_EXPECT_FALSE(test, __atomic_compare_exchange_n(&test_var, &tmp, 40L, |
| 1, __ATOMIC_RELAXED, |
| __ATOMIC_RELAXED)); |
| KUNIT_EXPECT_EQ(test, tmp, 30L); |
| KUNIT_EXPECT_EQ(test, test_var, 30L); |
| |
| KUNIT_EXPECT_EQ(test, 30L, __atomic_fetch_add(&test_var, 1, __ATOMIC_RELAXED)); |
| KUNIT_EXPECT_EQ(test, 31L, __atomic_fetch_sub(&test_var, 1, __ATOMIC_RELAXED)); |
| KUNIT_EXPECT_EQ(test, 30L, __atomic_fetch_and(&test_var, 0xf, __ATOMIC_RELAXED)); |
| KUNIT_EXPECT_EQ(test, 14L, __atomic_fetch_xor(&test_var, 0xf, __ATOMIC_RELAXED)); |
| KUNIT_EXPECT_EQ(test, 1L, __atomic_fetch_or(&test_var, 0xf0, __ATOMIC_RELAXED)); |
| KUNIT_EXPECT_EQ(test, 241L, __atomic_fetch_nand(&test_var, 0xf, __ATOMIC_RELAXED)); |
| KUNIT_EXPECT_EQ(test, -2L, test_var); |
| |
| __atomic_thread_fence(__ATOMIC_SEQ_CST); |
| __atomic_signal_fence(__ATOMIC_SEQ_CST); |
| |
| kcsan_disable_current(); |
| |
| match_never = report_available(); |
| } while (!end_test_checks(match_never)); |
| KUNIT_EXPECT_FALSE(test, match_never); |
| } |
| |
| __no_kcsan |
| static void test_1bit_value_change(struct kunit *test) |
| { |
| struct expect_report expect = { |
| .access = { |
| { test_kernel_read, &test_var, sizeof(test_var), 0 }, |
| { test_kernel_xor_1bit, &test_var, sizeof(test_var), __KCSAN_ACCESS_RW(KCSAN_ACCESS_WRITE) }, |
| }, |
| }; |
| bool match = false; |
| |
| begin_test_checks(test_kernel_read, test_kernel_xor_1bit); |
| do { |
| match = IS_ENABLED(CONFIG_KCSAN_PERMISSIVE) |
| ? report_available() |
| : report_matches(&expect); |
| } while (!end_test_checks(match)); |
| if (IS_ENABLED(CONFIG_KCSAN_PERMISSIVE)) |
| KUNIT_EXPECT_FALSE(test, match); |
| else |
| KUNIT_EXPECT_TRUE(test, match); |
| } |
| |
| __no_kcsan |
| static void test_correct_barrier(struct kunit *test) |
| { |
| struct expect_report expect = { |
| .access = { |
| { test_kernel_with_memorder, &test_var, sizeof(test_var), __KCSAN_ACCESS_RW(KCSAN_ACCESS_WRITE) }, |
| { test_kernel_with_memorder, &test_var, sizeof(test_var), __KCSAN_ACCESS_RW(0) }, |
| }, |
| }; |
| bool match_expect = false; |
| |
| test_struct.val[0] = 0; /* init unlocked */ |
| begin_test_checks(test_kernel_with_memorder, test_kernel_with_memorder); |
| do { |
| match_expect = report_matches_any_reordered(&expect); |
| } while (!end_test_checks(match_expect)); |
| KUNIT_EXPECT_FALSE(test, match_expect); |
| } |
| |
| __no_kcsan |
| static void test_missing_barrier(struct kunit *test) |
| { |
| struct expect_report expect = { |
| .access = { |
| { test_kernel_wrong_memorder, &test_var, sizeof(test_var), __KCSAN_ACCESS_RW(KCSAN_ACCESS_WRITE) }, |
| { test_kernel_wrong_memorder, &test_var, sizeof(test_var), __KCSAN_ACCESS_RW(0) }, |
| }, |
| }; |
| bool match_expect = false; |
| |
| test_struct.val[0] = 0; /* init unlocked */ |
| begin_test_checks(test_kernel_wrong_memorder, test_kernel_wrong_memorder); |
| do { |
| match_expect = report_matches_any_reordered(&expect); |
| } while (!end_test_checks(match_expect)); |
| if (IS_ENABLED(CONFIG_KCSAN_WEAK_MEMORY)) |
| KUNIT_EXPECT_TRUE(test, match_expect); |
| else |
| KUNIT_EXPECT_FALSE(test, match_expect); |
| } |
| |
| __no_kcsan |
| static void test_atomic_builtins_correct_barrier(struct kunit *test) |
| { |
| struct expect_report expect = { |
| .access = { |
| { test_kernel_atomic_builtin_with_memorder, &test_var, sizeof(test_var), __KCSAN_ACCESS_RW(KCSAN_ACCESS_WRITE) }, |
| { test_kernel_atomic_builtin_with_memorder, &test_var, sizeof(test_var), __KCSAN_ACCESS_RW(0) }, |
| }, |
| }; |
| bool match_expect = false; |
| |
| test_struct.val[0] = 0; /* init unlocked */ |
| begin_test_checks(test_kernel_atomic_builtin_with_memorder, |
| test_kernel_atomic_builtin_with_memorder); |
| do { |
| match_expect = report_matches_any_reordered(&expect); |
| } while (!end_test_checks(match_expect)); |
| KUNIT_EXPECT_FALSE(test, match_expect); |
| } |
| |
| __no_kcsan |
| static void test_atomic_builtins_missing_barrier(struct kunit *test) |
| { |
| struct expect_report expect = { |
| .access = { |
| { test_kernel_atomic_builtin_wrong_memorder, &test_var, sizeof(test_var), __KCSAN_ACCESS_RW(KCSAN_ACCESS_WRITE) }, |
| { test_kernel_atomic_builtin_wrong_memorder, &test_var, sizeof(test_var), __KCSAN_ACCESS_RW(0) }, |
| }, |
| }; |
| bool match_expect = false; |
| |
| test_struct.val[0] = 0; /* init unlocked */ |
| begin_test_checks(test_kernel_atomic_builtin_wrong_memorder, |
| test_kernel_atomic_builtin_wrong_memorder); |
| do { |
| match_expect = report_matches_any_reordered(&expect); |
| } while (!end_test_checks(match_expect)); |
| if (IS_ENABLED(CONFIG_KCSAN_WEAK_MEMORY)) |
| KUNIT_EXPECT_TRUE(test, match_expect); |
| else |
| KUNIT_EXPECT_FALSE(test, match_expect); |
| } |
| |
| /* |
| * Generate thread counts for all test cases. Values generated are in interval |
| * [2, 5] followed by exponentially increasing thread counts from 8 to 32. |
| * |
| * The thread counts are chosen to cover potentially interesting boundaries and |
| * corner cases (2 to 5), and then stress the system with larger counts. |
| */ |
| static const void *nthreads_gen_params(const void *prev, char *desc) |
| { |
| long nthreads = (long)prev; |
| |
| if (nthreads < 0 || nthreads >= 32) |
| nthreads = 0; /* stop */ |
| else if (!nthreads) |
| nthreads = 2; /* initial value */ |
| else if (nthreads < 5) |
| nthreads++; |
| else if (nthreads == 5) |
| nthreads = 8; |
| else |
| nthreads *= 2; |
| |
| if (!preempt_model_preemptible() || |
| !IS_ENABLED(CONFIG_KCSAN_INTERRUPT_WATCHER)) { |
| /* |
| * Without any preemption, keep 2 CPUs free for other tasks, one |
| * of which is the main test case function checking for |
| * completion or failure. |
| */ |
| const long min_unused_cpus = preempt_model_none() ? 2 : 0; |
| const long min_required_cpus = 2 + min_unused_cpus; |
| |
| if (num_online_cpus() < min_required_cpus) { |
| pr_err_once("Too few online CPUs (%u < %ld) for test\n", |
| num_online_cpus(), min_required_cpus); |
| nthreads = 0; |
| } else if (nthreads >= num_online_cpus() - min_unused_cpus) { |
| /* Use negative value to indicate last param. */ |
| nthreads = -(num_online_cpus() - min_unused_cpus); |
| pr_warn_once("Limiting number of threads to %ld (only %d online CPUs)\n", |
| -nthreads, num_online_cpus()); |
| } |
| } |
| |
| snprintf(desc, KUNIT_PARAM_DESC_SIZE, "threads=%ld", abs(nthreads)); |
| return (void *)nthreads; |
| } |
| |
| #define KCSAN_KUNIT_CASE(test_name) KUNIT_CASE_PARAM(test_name, nthreads_gen_params) |
| static struct kunit_case kcsan_test_cases[] = { |
| KUNIT_CASE(test_barrier_nothreads), |
| KCSAN_KUNIT_CASE(test_basic), |
| KCSAN_KUNIT_CASE(test_concurrent_races), |
| KCSAN_KUNIT_CASE(test_novalue_change), |
| KCSAN_KUNIT_CASE(test_novalue_change_exception), |
| KCSAN_KUNIT_CASE(test_unknown_origin), |
| KCSAN_KUNIT_CASE(test_write_write_assume_atomic), |
| KCSAN_KUNIT_CASE(test_write_write_struct), |
| 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), |
| KCSAN_KUNIT_CASE(test_assert_exclusive_access), |
| KCSAN_KUNIT_CASE(test_assert_exclusive_access_writer), |
| KCSAN_KUNIT_CASE(test_assert_exclusive_bits_change), |
| KCSAN_KUNIT_CASE(test_assert_exclusive_bits_nochange), |
| KCSAN_KUNIT_CASE(test_assert_exclusive_writer_scoped), |
| KCSAN_KUNIT_CASE(test_assert_exclusive_access_scoped), |
| KCSAN_KUNIT_CASE(test_jiffies_noreport), |
| KCSAN_KUNIT_CASE(test_seqlock_noreport), |
| KCSAN_KUNIT_CASE(test_atomic_builtins), |
| KCSAN_KUNIT_CASE(test_1bit_value_change), |
| KCSAN_KUNIT_CASE(test_correct_barrier), |
| KCSAN_KUNIT_CASE(test_missing_barrier), |
| KCSAN_KUNIT_CASE(test_atomic_builtins_correct_barrier), |
| KCSAN_KUNIT_CASE(test_atomic_builtins_missing_barrier), |
| {}, |
| }; |
| |
| /* ===== End test cases ===== */ |
| |
| /* Concurrent accesses from interrupts. */ |
| __no_kcsan |
| static void access_thread_timer(struct timer_list *timer) |
| { |
| static atomic_t cnt = ATOMIC_INIT(0); |
| unsigned int idx; |
| void (*func)(void); |
| |
| idx = (unsigned int)atomic_inc_return(&cnt) % ARRAY_SIZE(access_kernels); |
| /* Acquire potential initialization. */ |
| func = smp_load_acquire(&access_kernels[idx]); |
| if (func) |
| func(); |
| } |
| |
| /* The main loop for each thread. */ |
| __no_kcsan |
| static int access_thread(void *arg) |
| { |
| struct timer_list timer; |
| unsigned int cnt = 0; |
| unsigned int idx; |
| void (*func)(void); |
| |
| timer_setup_on_stack(&timer, access_thread_timer, 0); |
| do { |
| might_sleep(); |
| |
| if (!timer_pending(&timer)) |
| mod_timer(&timer, jiffies + 1); |
| else { |
| /* Iterate through all kernels. */ |
| idx = cnt++ % ARRAY_SIZE(access_kernels); |
| /* Acquire potential initialization. */ |
| func = smp_load_acquire(&access_kernels[idx]); |
| if (func) |
| func(); |
| } |
| } while (!torture_must_stop()); |
| del_timer_sync(&timer); |
| destroy_timer_on_stack(&timer); |
| |
| torture_kthread_stopping("access_thread"); |
| return 0; |
| } |
| |
| __no_kcsan |
| static int test_init(struct kunit *test) |
| { |
| unsigned long flags; |
| int nthreads; |
| int i; |
| |
| spin_lock_irqsave(&observed.lock, flags); |
| for (i = 0; i < ARRAY_SIZE(observed.lines); ++i) |
| observed.lines[i][0] = '\0'; |
| observed.nlines = 0; |
| spin_unlock_irqrestore(&observed.lock, flags); |
| |
| if (strstr(test->name, "nothreads")) |
| return 0; |
| |
| if (!torture_init_begin((char *)test->name, 1)) |
| return -EBUSY; |
| |
| if (WARN_ON(threads)) |
| goto err; |
| |
| for (i = 0; i < ARRAY_SIZE(access_kernels); ++i) { |
| if (WARN_ON(access_kernels[i])) |
| goto err; |
| } |
| |
| nthreads = abs((long)test->param_value); |
| if (WARN_ON(!nthreads)) |
| goto err; |
| |
| threads = kcalloc(nthreads + 1, sizeof(struct task_struct *), GFP_KERNEL); |
| if (WARN_ON(!threads)) |
| goto err; |
| |
| threads[nthreads] = NULL; |
| for (i = 0; i < nthreads; ++i) { |
| if (torture_create_kthread(access_thread, NULL, threads[i])) |
| goto err; |
| } |
| |
| torture_init_end(); |
| |
| return 0; |
| |
| err: |
| kfree(threads); |
| threads = NULL; |
| torture_init_end(); |
| return -EINVAL; |
| } |
| |
| __no_kcsan |
| static void test_exit(struct kunit *test) |
| { |
| struct task_struct **stop_thread; |
| int i; |
| |
| if (strstr(test->name, "nothreads")) |
| return; |
| |
| if (torture_cleanup_begin()) |
| return; |
| |
| for (i = 0; i < ARRAY_SIZE(access_kernels); ++i) |
| WRITE_ONCE(access_kernels[i], NULL); |
| |
| if (threads) { |
| for (stop_thread = threads; *stop_thread; stop_thread++) |
| torture_stop_kthread(reader_thread, *stop_thread); |
| |
| kfree(threads); |
| threads = NULL; |
| } |
| |
| torture_cleanup_end(); |
| } |
| |
| __no_kcsan |
| 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)); |
| } |
| |
| __no_kcsan |
| static void unregister_tracepoints(struct tracepoint *tp, void *ignore) |
| { |
| if (!strcmp(tp->name, "console")) |
| tracepoint_probe_unregister(tp, probe_console, NULL); |
| } |
| |
| static int kcsan_suite_init(struct kunit_suite *suite) |
| { |
| /* |
| * 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 kcsan_suite_exit(struct kunit_suite *suite) |
| { |
| for_each_kernel_tracepoint(unregister_tracepoints, NULL); |
| tracepoint_synchronize_unregister(); |
| } |
| |
| static struct kunit_suite kcsan_test_suite = { |
| .name = "kcsan", |
| .test_cases = kcsan_test_cases, |
| .init = test_init, |
| .exit = test_exit, |
| .suite_init = kcsan_suite_init, |
| .suite_exit = kcsan_suite_exit, |
| }; |
| |
| kunit_test_suites(&kcsan_test_suite); |
| |
| MODULE_LICENSE("GPL v2"); |
| MODULE_AUTHOR("Marco Elver <elver@google.com>"); |