Test that if CRCs are computed in task, softirq, and hardirq context
concurrently, then all results are as expected. Implement this using
kunit_run_irq_test() which is also used by the lib/crypto/ tests.
As with the corresponding lib/crypto/ tests, the purpose of this is to
test fallback code paths and to exercise edge cases in the
architecture's support for in-kernel FPU/SIMD/vector.
Remove the code from crc_test() that sometimes disabled interrupts, as
that was just an incomplete attempt to achieve similar test coverage.
Signed-off-by: Eric Biggers <ebiggers@xxxxxxxxxx>
---
lib/crc/tests/crc_kunit.c | 62 +++++++++++++++++++++++++++++++++------
1 file changed, 53 insertions(+), 9 deletions(-)
diff --git a/lib/crc/tests/crc_kunit.c b/lib/crc/tests/crc_kunit.c
index f08d985d8860e..9a450e25ac811 100644
--- a/lib/crc/tests/crc_kunit.c
+++ b/lib/crc/tests/crc_kunit.c
@@ -4,10 +4,11 @@
*
* Copyright 2024 Google LLC
*
* Author: Eric Biggers <ebiggers@xxxxxxxxxx>
*/
+#include <kunit/run-in-irq-context.h>
#include <kunit/test.h>
#include <linux/crc7.h>
#include <linux/crc16.h>
#include <linux/crc-t10dif.h>
#include <linux/crc32.h>
@@ -139,19 +140,66 @@ static size_t generate_random_length(size_t max_length)
break;
}
return len % (max_length + 1);
}
+#define IRQ_TEST_DATA_LEN 512
+#define IRQ_TEST_NUM_BUFFERS 3 /* matches max concurrency level */
+
+struct crc_irq_test_state {
+ const struct crc_variant *v;
+ u64 initial_crc;
+ u64 expected_crcs[IRQ_TEST_NUM_BUFFERS];
+ atomic_t seqno;
+};
+
+/*
+ * Compute the CRC of one of the test messages and verify that it matches the
+ * expected CRC from @state->expected_crcs. To increase the chance of detecting
+ * problems, cycle through multiple messages.
+ */
+static bool crc_irq_test_func(void *state_)
+{
+ struct crc_irq_test_state *state = state_;
+ const struct crc_variant *v = state->v;
+ u32 i = (u32)atomic_inc_return(&state->seqno) % IRQ_TEST_NUM_BUFFERS;
+ u64 actual_crc = v->func(state->initial_crc,
+ &test_buffer[i * IRQ_TEST_DATA_LEN],
+ IRQ_TEST_DATA_LEN);
+
+ return actual_crc == state->expected_crcs[i];
+}
+
+/*
+ * Test that if CRCs are computed in task, softirq, and hardirq context
+ * concurrently, then all results are as expected.
+ */
+static void crc_interrupt_context_test(struct kunit *test,
+ const struct crc_variant *v)
+{
+ struct crc_irq_test_state state = {
+ .v = v,
+ .initial_crc = generate_random_initial_crc(v),
+ };
+
+ for (int i = 0; i < IRQ_TEST_NUM_BUFFERS; i++) {
+ state.expected_crcs[i] = crc_ref(
+ v, state.initial_crc,
+ &test_buffer[i * IRQ_TEST_DATA_LEN], IRQ_TEST_DATA_LEN);
+ }
+
+ kunit_run_irq_test(test, crc_irq_test_func, 100000, &state);
+}
+
/* Test that v->func gives the same CRCs as a reference implementation. */
static void crc_test(struct kunit *test, const struct crc_variant *v)
{
size_t i;
for (i = 0; i < CRC_KUNIT_NUM_TEST_ITERS; i++) {
u64 init_crc, expected_crc, actual_crc;
size_t len, offset;
- bool nosimd;
init_crc = generate_random_initial_crc(v);
len = generate_random_length(CRC_KUNIT_MAX_LEN);
/* Generate a random offset. */
@@ -166,26 +214,22 @@ static void crc_test(struct kunit *test, const struct crc_variant *v)
if (rand32() % 8 == 0)
/* Refresh the data occasionally. */
prandom_bytes_state(&rng, &test_buffer[offset], len);
- nosimd = rand32() % 8 == 0;
-
/*
* Compute the CRC, and verify that it equals the CRC computed
* by a simple bit-at-a-time reference implementation.
*/
expected_crc = crc_ref(v, init_crc, &test_buffer[offset], len);
- if (nosimd)
- local_irq_disable();
actual_crc = v->func(init_crc, &test_buffer[offset], len);
- if (nosimd)
- local_irq_enable();
KUNIT_EXPECT_EQ_MSG(test, expected_crc, actual_crc,
- "Wrong result with len=%zu offset=%zu nosimd=%d",
- len, offset, nosimd);
+ "Wrong result with len=%zu offset=%zu",
+ len, offset);
}
+
+ crc_interrupt_context_test(test, v);
}
static __always_inline void
crc_benchmark(struct kunit *test,
u64 (*crc_func)(u64 crc, const u8 *p, size_t len))
--
2.50.1
