Merge tag 'libcrypto-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiggers/linux

Pull crypto library fix from Eric Biggers:
 "Fix the kunit_run_irq_test() function (which I recently added for the
  CRC and crypto tests) to be less timing-dependent.

  This fixes flakiness in the polyval kunit test suite"

* tag 'libcrypto-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiggers/linux:
  kunit: Enforce task execution in {soft,hard}irq contexts

1 files changed, 33 insertions, 20 deletions

diff --git a/include/kunit/run-in-irq-context.h b/include/kunit/run-in-irq-context.h
index 108e96433ea4..c89b1b1b12dd 100644
--- a/include/kunit/run-in-irq-context.h
+++ b/include/kunit/run-in-irq-context.h
@@ -20,8 +20,8 @@ struct kunit_irq_test_state {
 	bool task_func_reported_failure;
 	bool hardirq_func_reported_failure;
 	bool softirq_func_reported_failure;
-	unsigned long hardirq_func_calls;
-	unsigned long softirq_func_calls;
+	atomic_t hardirq_func_calls;
+	atomic_t softirq_func_calls;
 	struct hrtimer timer;
 	struct work_struct bh_work;
 };
@@ -32,7 +32,7 @@ static enum hrtimer_restart kunit_irq_test_timer_func(struct hrtimer *timer)
 		container_of(timer, typeof(*state), timer);
 
 	WARN_ON_ONCE(!in_hardirq());
-	state->hardirq_func_calls++;
+	atomic_inc(&state->hardirq_func_calls);
 
 	if (!state->func(state->test_specific_state))
 		state->hardirq_func_reported_failure = true;
@@ -48,7 +48,7 @@ static void kunit_irq_test_bh_work_func(struct work_struct *work)
 		container_of(work, typeof(*state), bh_work);
 
 	WARN_ON_ONCE(!in_serving_softirq());
-	state->softirq_func_calls++;
+	atomic_inc(&state->softirq_func_calls);
 
 	if (!state->func(state->test_specific_state))
 		state->softirq_func_reported_failure = true;
@@ -59,7 +59,10 @@ static void kunit_irq_test_bh_work_func(struct work_struct *work)
  * hardirq context concurrently, and reports a failure to KUnit if any
  * invocation of @func in any context returns false.  @func is passed
  * @test_specific_state as its argument.  At most 3 invocations of @func will
- * run concurrently: one in each of task, softirq, and hardirq context.
+ * run concurrently: one in each of task, softirq, and hardirq context.  @func
+ * will continue running until either @max_iterations calls have been made (so
+ * long as at least one each runs in task, softirq, and hardirq contexts), or
+ * one second has passed.
  *
  * The main purpose of this interrupt context testing is to validate fallback
  * code paths that run in contexts where the normal code path cannot be used,
@@ -85,6 +88,8 @@ static inline void kunit_run_irq_test(struct kunit *test, bool (*func)(void *),
 		.test_specific_state = test_specific_state,
 	};
 	unsigned long end_jiffies;
+	int hardirq_calls, softirq_calls;
+	bool allctx = false;
 
 	/*
 	 * Set up a hrtimer (the way we access hardirq context) and a work
@@ -94,14 +99,25 @@ static inline void kunit_run_irq_test(struct kunit *test, bool (*func)(void *),
 			       CLOCK_MONOTONIC, HRTIMER_MODE_REL_HARD);
 	INIT_WORK_ONSTACK(&state.bh_work, kunit_irq_test_bh_work_func);
 
-	/* Run for up to max_iterations or 1 second, whichever comes first. */
+	/*
+	 * Run for up to max_iterations (including at least one task, softirq,
+	 * and hardirq), or 1 second, whichever comes first.
+	 */
 	end_jiffies = jiffies + HZ;
 	hrtimer_start(&state.timer, KUNIT_IRQ_TEST_HRTIMER_INTERVAL,
 		      HRTIMER_MODE_REL_HARD);
-	for (int i = 0; i < max_iterations && !time_after(jiffies, end_jiffies);
-	     i++) {
+	for (int task_calls = 0, calls = 0;
+	     ((calls < max_iterations) || !allctx) &&
+	     !time_after(jiffies, end_jiffies);
+	     task_calls++) {
 		if (!func(test_specific_state))
 			state.task_func_reported_failure = true;
+
+		hardirq_calls = atomic_read(&state.hardirq_func_calls);
+		softirq_calls = atomic_read(&state.softirq_func_calls);
+		calls = task_calls + hardirq_calls + softirq_calls;
+		allctx = (task_calls > 0) && (hardirq_calls > 0) &&
+			 (softirq_calls > 0);
 	}
 
 	/* Cancel the timer and work. */
@@ -109,21 +125,18 @@ static inline void kunit_run_irq_test(struct kunit *test, bool (*func)(void *),
 	flush_work(&state.bh_work);
 
 	/* Sanity check: the timer and BH functions should have been run. */
-	KUNIT_EXPECT_GT_MSG(test, state.hardirq_func_calls, 0,
+	KUNIT_EXPECT_GT_MSG(test, atomic_read(&state.hardirq_func_calls), 0,
 			    "Timer function was not called");
-	KUNIT_EXPECT_GT_MSG(test, state.softirq_func_calls, 0,
+	KUNIT_EXPECT_GT_MSG(test, atomic_read(&state.softirq_func_calls), 0,
 			    "BH work function was not called");
 
-	/* Check for incorrect hash values reported from any context. */
-	KUNIT_EXPECT_FALSE_MSG(
-		test, state.task_func_reported_failure,
-		"Incorrect hash values reported from task context");
-	KUNIT_EXPECT_FALSE_MSG(
-		test, state.hardirq_func_reported_failure,
-		"Incorrect hash values reported from hardirq context");
-	KUNIT_EXPECT_FALSE_MSG(
-		test, state.softirq_func_reported_failure,
-		"Incorrect hash values reported from softirq context");
+	/* Check for failure reported from any context. */
+	KUNIT_EXPECT_FALSE_MSG(test, state.task_func_reported_failure,
+			       "Failure reported from task context");
+	KUNIT_EXPECT_FALSE_MSG(test, state.hardirq_func_reported_failure,
+			       "Failure reported from hardirq context");
+	KUNIT_EXPECT_FALSE_MSG(test, state.softirq_func_reported_failure,
+			       "Failure reported from softirq context");
 }
 
 #endif /* _KUNIT_RUN_IN_IRQ_CONTEXT_H */