[PATCH v2 10/23] kcsan: test: Match reordered or normal accesses

From: Marco Elver
Date: Thu Nov 18 2021 - 03:12:05 EST

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Due to reordering accesses with weak memory modeling, any access can now
appear as "(reordered)".

Match any permutation of accesses if CONFIG_KCSAN_WEAK_MEMORY=y, so that
we effectively match an access if it is denoted "(reordered)" or not.

Signed-off-by: Marco Elver <elver@xxxxxxxxxx>
---
kernel/kcsan/kcsan_test.c | 92 +++++++++++++++++++++++++++------------
1 file changed, 63 insertions(+), 29 deletions(-)

diff --git a/kernel/kcsan/kcsan_test.c b/kernel/kcsan/kcsan_test.c
index 6e3c2b8bc608..ec054879201b 100644
--- a/kernel/kcsan/kcsan_test.c
+++ b/kernel/kcsan/kcsan_test.c
@@ -151,7 +151,7 @@ struct expect_report {

/* Check observed report matches information in @r. */
__no_kcsan
-static bool report_matches(const struct expect_report *r)
+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;
@@ -253,6 +253,40 @@ static bool report_matches(const struct expect_report *r)
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;
@@ -438,13 +472,13 @@ static noinline void test_kernel_xor_1bit(void)
__no_kcsan
static void test_basic(struct kunit *test)
{
- const struct expect_report expect = {
+ 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 },
},
};
- static const struct expect_report never = {
+ struct expect_report never = {
.access = {
{ test_kernel_read, &test_var, sizeof(test_var), 0 },
{ test_kernel_read, &test_var, sizeof(test_var), 0 },
@@ -469,14 +503,14 @@ static void test_basic(struct kunit *test)
__no_kcsan
static void test_concurrent_races(struct kunit *test)
{
- const struct expect_report expect = {
+ 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) },
},
};
- static const struct expect_report never = {
+ struct expect_report never = {
.access = {
{ test_kernel_rmw_array, NULL, 0, 0 },
{ test_kernel_rmw_array, NULL, 0, 0 },
@@ -498,13 +532,13 @@ static void test_concurrent_races(struct kunit *test)
__no_kcsan
static void test_novalue_change(struct kunit *test)
{
- const struct expect_report expect_rw = {
+ 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 },
},
};
- const struct expect_report expect_ww = {
+ 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 },
@@ -530,13 +564,13 @@ static void test_novalue_change(struct kunit *test)
__no_kcsan
static void test_novalue_change_exception(struct kunit *test)
{
- const struct expect_report expect_rw = {
+ 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 },
},
};
- const struct expect_report expect_ww = {
+ 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 },
@@ -556,7 +590,7 @@ static void test_novalue_change_exception(struct kunit *test)
__no_kcsan
static void test_unknown_origin(struct kunit *test)
{
- const struct expect_report expect = {
+ struct expect_report expect = {
.access = {
{ test_kernel_read, &test_var, sizeof(test_var), 0 },
{ NULL },
@@ -578,7 +612,7 @@ static void test_unknown_origin(struct kunit *test)
__no_kcsan
static void test_write_write_assume_atomic(struct kunit *test)
{
- const struct expect_report expect = {
+ 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 },
@@ -604,7 +638,7 @@ static void test_write_write_assume_atomic(struct kunit *test)
__no_kcsan
static void test_write_write_struct(struct kunit *test)
{
- const struct expect_report expect = {
+ 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 },
@@ -626,7 +660,7 @@ static void test_write_write_struct(struct kunit *test)
__no_kcsan
static void test_write_write_struct_part(struct kunit *test)
{
- const struct expect_report expect = {
+ 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 },
@@ -658,7 +692,7 @@ static void test_read_atomic_write_atomic(struct kunit *test)
__no_kcsan
static void test_read_plain_atomic_write(struct kunit *test)
{
- const struct expect_report expect = {
+ 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 },
@@ -679,7 +713,7 @@ static void test_read_plain_atomic_write(struct kunit *test)
__no_kcsan
static void test_read_plain_atomic_rmw(struct kunit *test)
{
- const struct expect_report expect = {
+ struct expect_report expect = {
.access = {
{ test_kernel_read, &test_var, sizeof(test_var), 0 },
{ test_kernel_atomic_rmw, &test_var, sizeof(test_var),
@@ -701,13 +735,13 @@ static void test_read_plain_atomic_rmw(struct kunit *test)
__no_kcsan
static void test_zero_size_access(struct kunit *test)
{
- const struct expect_report expect = {
+ 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 },
},
};
- const struct expect_report never = {
+ 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 },
@@ -741,7 +775,7 @@ static void test_data_race(struct kunit *test)
__no_kcsan
static void test_assert_exclusive_writer(struct kunit *test)
{
- const struct expect_report expect = {
+ 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 },
@@ -759,7 +793,7 @@ static void test_assert_exclusive_writer(struct kunit *test)
__no_kcsan
static void test_assert_exclusive_access(struct kunit *test)
{
- const struct expect_report expect = {
+ 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 },
@@ -777,19 +811,19 @@ static void test_assert_exclusive_access(struct kunit *test)
__no_kcsan
static void test_assert_exclusive_access_writer(struct kunit *test)
{
- const struct expect_report expect_access_writer = {
+ 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 },
},
};
- const struct expect_report expect_access_access = {
+ 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 },
},
};
- const struct expect_report never = {
+ 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 },
@@ -813,7 +847,7 @@ static void test_assert_exclusive_access_writer(struct kunit *test)
__no_kcsan
static void test_assert_exclusive_bits_change(struct kunit *test)
{
- const struct expect_report expect = {
+ 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),
@@ -844,13 +878,13 @@ static void test_assert_exclusive_bits_nochange(struct kunit *test)
__no_kcsan
static void test_assert_exclusive_writer_scoped(struct kunit *test)
{
- const struct expect_report expect_start = {
+ 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 },
},
};
- const struct expect_report expect_inscope = {
+ 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 },
@@ -871,16 +905,16 @@ static void test_assert_exclusive_writer_scoped(struct kunit *test)
__no_kcsan
static void test_assert_exclusive_access_scoped(struct kunit *test)
{
- const struct expect_report expect_start1 = {
+ 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 },
},
};
- const struct expect_report expect_start2 = {
+ struct expect_report expect_start2 = {
.access = { expect_start1.access[0], expect_start1.access[0] },
};
- const struct expect_report expect_inscope = {
+ 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 },
@@ -985,7 +1019,7 @@ static void test_atomic_builtins(struct kunit *test)
__no_kcsan
static void test_1bit_value_change(struct kunit *test)
{
- const struct expect_report expect = {
+ 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) },
--
2.34.0.rc2.393.gf8c9666880-goog

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Previous message: Marco Elver: "[PATCH v2 09/23] kcsan: Document modeling of weak memory"
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Next in thread: Marco Elver: "[PATCH v2 07/23] kcsan: Call scoped accesses reordered in reports"
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