| Author | Tokens | Token Proportion | Commits | Commit Proportion |
|---|---|---|---|---|
| Marco Elver | 8277 | 99.51% | 19 | 79.17% |
| Max Filippov | 26 | 0.31% | 1 | 4.17% |
| Matthew Wilcox | 6 | 0.07% | 1 | 4.17% |
| Pavankumar Kondeti | 4 | 0.05% | 1 | 4.17% |
| Valentin Schneider | 4 | 0.05% | 1 | 4.17% |
| Arnd Bergmann | 1 | 0.01% | 1 | 4.17% |
| Total | 8318 | 24 |
// 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; expect = kmalloc(sizeof(observed.lines), GFP_KERNEL); if (WARN_ON(!expect)) 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); kfree(expect); 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); KCSAN_EXPECT_READ_BARRIER(xor_unlock_is_negative_byte(1, &test_var), true); KCSAN_EXPECT_WRITE_BARRIER(xor_unlock_is_negative_byte(1, &test_var), true); KCSAN_EXPECT_RW_BARRIER(xor_unlock_is_negative_byte(1, &test_var), true); 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(void) { register_trace_console(probe_console, NULL); } __no_kcsan static void unregister_tracepoints(void) { unregister_trace_console(probe_console, NULL); } static int kcsan_suite_init(struct kunit_suite *suite) { register_tracepoints(); return 0; } static void kcsan_suite_exit(struct kunit_suite *suite) { unregister_tracepoints(); 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>");
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