scftorture: Count single_rpc offline failures in statistics outputgrafted

scf_torture_stats_print() aggregates each invoker thread's counters
into a local scf_statistics structure before printing, but the
n_single_rpc_ofl field is missing from the aggregation loop.  As a
result, the "single_rpc_ofl" value printed in the statistics line is
always zero, even when smp_call_function_single() invocations for the
RPC test have failed due to offline CPUs and been counted by the
invoker threads.

Add the missing accumulation so that the printed value reflects the
actual counts.

Signed-off-by: Joel Fernandes <joelagnelf@nvidia.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

1 files changed, 198 insertions, 0 deletions

diff --git a/lib/kunit/backtrace-suppression-test.c b/lib/kunit/backtrace-suppression-test.c
new file mode 100644
index 000000000..7a2a59c6a
--- /dev/null
+++ b/lib/kunit/backtrace-suppression-test.c
@@ -0,0 +1,198 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * KUnit test for suppressing warning tracebacks.
+ *
+ * Copyright (C) 2024, Guenter Roeck
+ * Author: Guenter Roeck <linux@roeck-us.net>
+ */
+
+#include <kunit/test.h>
+#include <linux/bug.h>
+#include <linux/completion.h>
+#include <linux/kthread.h>
+
+static void backtrace_suppression_test_warn_direct(struct kunit *test)
+{
+	if (!IS_ENABLED(CONFIG_BUG))
+		kunit_skip(test, "requires CONFIG_BUG");
+
+	kunit_warning_suppress(test) {
+		WARN(1, "This backtrace should be suppressed");
+		/*
+		 * Count must be checked inside the scope; the handle
+		 * is not accessible after the block exits.
+		 */
+		KUNIT_EXPECT_SUPPRESSED_WARNING_COUNT(test, 1);
+	}
+	KUNIT_EXPECT_FALSE(test, kunit_has_active_suppress_warning());
+}
+
+static noinline void trigger_backtrace_warn(void)
+{
+	WARN(1, "This backtrace should be suppressed");
+}
+
+static void backtrace_suppression_test_warn_indirect(struct kunit *test)
+{
+	if (!IS_ENABLED(CONFIG_BUG))
+		kunit_skip(test, "requires CONFIG_BUG");
+
+	kunit_warning_suppress(test) {
+		trigger_backtrace_warn();
+		KUNIT_EXPECT_SUPPRESSED_WARNING_COUNT(test, 1);
+	}
+}
+
+static void backtrace_suppression_test_warn_multi(struct kunit *test)
+{
+	if (!IS_ENABLED(CONFIG_BUG))
+		kunit_skip(test, "requires CONFIG_BUG");
+
+	kunit_warning_suppress(test) {
+		WARN(1, "This backtrace should be suppressed");
+		trigger_backtrace_warn();
+		KUNIT_EXPECT_SUPPRESSED_WARNING_COUNT(test, 2);
+	}
+}
+
+static void backtrace_suppression_test_warn_on_direct(struct kunit *test)
+{
+	if (!IS_ENABLED(CONFIG_BUG))
+		kunit_skip(test, "requires CONFIG_BUG");
+	if (!IS_ENABLED(CONFIG_DEBUG_BUGVERBOSE) && !IS_ENABLED(CONFIG_KALLSYMS))
+		kunit_skip(test, "requires CONFIG_DEBUG_BUGVERBOSE or CONFIG_KALLSYMS");
+
+	kunit_warning_suppress(test) {
+		WARN_ON(1);
+		KUNIT_EXPECT_SUPPRESSED_WARNING_COUNT(test, 1);
+	}
+}
+
+static noinline void trigger_backtrace_warn_on(void)
+{
+	WARN_ON(1);
+}
+
+static void backtrace_suppression_test_warn_on_indirect(struct kunit *test)
+{
+	if (!IS_ENABLED(CONFIG_BUG))
+		kunit_skip(test, "requires CONFIG_BUG");
+	if (!IS_ENABLED(CONFIG_DEBUG_BUGVERBOSE))
+		kunit_skip(test, "requires CONFIG_DEBUG_BUGVERBOSE");
+
+	kunit_warning_suppress(test) {
+		trigger_backtrace_warn_on();
+		KUNIT_EXPECT_SUPPRESSED_WARNING_COUNT(test, 1);
+	}
+}
+
+static void backtrace_suppression_test_count(struct kunit *test)
+{
+	if (!IS_ENABLED(CONFIG_BUG))
+		kunit_skip(test, "requires CONFIG_BUG");
+
+	kunit_warning_suppress(test) {
+		KUNIT_EXPECT_SUPPRESSED_WARNING_COUNT(test, 0);
+
+		WARN(1, "suppressed");
+		KUNIT_EXPECT_SUPPRESSED_WARNING_COUNT(test, 1);
+
+		WARN(1, "suppressed again");
+		KUNIT_EXPECT_SUPPRESSED_WARNING_COUNT(test, 2);
+	}
+}
+
+static void backtrace_suppression_test_active_state(struct kunit *test)
+{
+	KUNIT_EXPECT_FALSE(test, kunit_has_active_suppress_warning());
+
+	kunit_warning_suppress(test) {
+		KUNIT_EXPECT_TRUE(test, kunit_has_active_suppress_warning());
+	}
+
+	KUNIT_EXPECT_FALSE(test, kunit_has_active_suppress_warning());
+
+	kunit_warning_suppress(test) {
+		KUNIT_EXPECT_TRUE(test, kunit_has_active_suppress_warning());
+	}
+
+	KUNIT_EXPECT_FALSE(test, kunit_has_active_suppress_warning());
+}
+
+static void backtrace_suppression_test_multi_scope(struct kunit *test)
+{
+	struct kunit_suppressed_warning *sw1, *sw2;
+
+	if (!IS_ENABLED(CONFIG_BUG))
+		kunit_skip(test, "requires CONFIG_BUG");
+	if (!IS_ENABLED(CONFIG_DEBUG_BUGVERBOSE))
+		kunit_skip(test, "requires CONFIG_DEBUG_BUGVERBOSE");
+
+	sw1 = kunit_start_suppress_warning(test);
+	trigger_backtrace_warn_on();
+	WARN(1, "suppressed by sw1");
+	kunit_end_suppress_warning(test, sw1);
+
+	sw2 = kunit_start_suppress_warning(test);
+	WARN(1, "suppressed by sw2");
+	kunit_end_suppress_warning(test, sw2);
+
+	KUNIT_EXPECT_EQ(test, kunit_suppressed_warning_count(sw1), 2);
+	KUNIT_EXPECT_EQ(test, kunit_suppressed_warning_count(sw2), 1);
+}
+
+struct cross_kthread_data {
+	bool was_active;
+	struct completion done;
+};
+
+static int cross_kthread_fn(void *data)
+{
+	struct cross_kthread_data *d = data;
+
+	d->was_active = kunit_has_active_suppress_warning();
+	complete(&d->done);
+	while (!kthread_should_stop())
+		schedule();
+	return 0;
+}
+
+static void backtrace_suppression_test_cross_kthread(struct kunit *test)
+{
+	struct cross_kthread_data data;
+	struct task_struct *task;
+
+	data.was_active = false;
+	init_completion(&data.done);
+
+	kunit_warning_suppress(test) {
+		task = kthread_run(cross_kthread_fn, &data, "kunit-cross-test");
+		KUNIT_ASSERT_FALSE(test, IS_ERR(task));
+		wait_for_completion(&data.done);
+		kthread_stop(task);
+	}
+
+	KUNIT_EXPECT_FALSE(test, data.was_active);
+}
+
+static struct kunit_case backtrace_suppression_test_cases[] = {
+	KUNIT_CASE(backtrace_suppression_test_warn_direct),
+	KUNIT_CASE(backtrace_suppression_test_warn_indirect),
+	KUNIT_CASE(backtrace_suppression_test_warn_multi),
+	KUNIT_CASE(backtrace_suppression_test_warn_on_direct),
+	KUNIT_CASE(backtrace_suppression_test_warn_on_indirect),
+	KUNIT_CASE(backtrace_suppression_test_count),
+	KUNIT_CASE(backtrace_suppression_test_active_state),
+	KUNIT_CASE(backtrace_suppression_test_multi_scope),
+	KUNIT_CASE(backtrace_suppression_test_cross_kthread),
+	{}
+};
+
+static struct kunit_suite backtrace_suppression_test_suite = {
+	.name = "backtrace-suppression-test",
+	.test_cases = backtrace_suppression_test_cases,
+};
+kunit_test_suites(&backtrace_suppression_test_suite);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("KUnit test to verify warning backtrace suppression");