From: Guenter Roeck <[email protected]> Add unit tests to verify that warning backtrace suppression works.
Tests cover all three API forms: - Scoped: kunit_warning_suppress() with in-block count verification and post-block inactivity check. - Manual macros: KUNIT_START/END_SUPPRESSED_WARNING() with WARN() and WARN_ON(), both direct and through helper functions, as well as multiple warnings in a single block. - Direct functions: kunit_start/end_suppress_warning() with sequential independent suppression blocks and per-block counts. Furthermore, tests verify incremental warning counting, that kunit_has_active_suppress_warning() transitions correctly around suppression boundaries, and that suppression active in the test kthread does not leak to a separate kthread. If backtrace suppression does _not_ work, the unit tests will likely trigger unsuppressed backtraces, which should actually help to get the affected architectures / platforms fixed. Tested-by: Linux Kernel Functional Testing <[email protected]> Acked-by: Dan Carpenter <[email protected]> Reviewed-by: Kees Cook <[email protected]> Signed-off-by: Guenter Roeck <[email protected]> Signed-off-by: Alessandro Carminati <[email protected]> Reviewed-by: David Gow <[email protected]> Signed-off-by: Albert Esteve <[email protected]> --- lib/kunit/Makefile | 1 + lib/kunit/backtrace-suppression-test.c | 184 +++++++++++++++++++++++++++++++++ 2 files changed, 185 insertions(+) diff --git a/lib/kunit/Makefile b/lib/kunit/Makefile index 4592f9d0aa8dd..2e8a6b71a2ab0 100644 --- a/lib/kunit/Makefile +++ b/lib/kunit/Makefile @@ -22,6 +22,7 @@ obj-$(if $(CONFIG_KUNIT),y) += hooks.o obj-$(CONFIG_KUNIT_TEST) += kunit-test.o obj-$(CONFIG_KUNIT_TEST) += platform-test.o +obj-$(CONFIG_KUNIT_TEST) += backtrace-suppression-test.o # string-stream-test compiles built-in only. ifeq ($(CONFIG_KUNIT_TEST),y) diff --git a/lib/kunit/backtrace-suppression-test.c b/lib/kunit/backtrace-suppression-test.c new file mode 100644 index 0000000000000..0e6fb685d2cbb --- /dev/null +++ b/lib/kunit/backtrace-suppression-test.c @@ -0,0 +1,184 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * KUnit test for suppressing warning tracebacks. + * + * Copyright (C) 2024, Guenter Roeck + * Author: Guenter Roeck <[email protected]> + */ + +#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) +{ + 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 void trigger_backtrace_warn(void) +{ + WARN(1, "This backtrace should be suppressed"); +} + +static void backtrace_suppression_test_warn_indirect(struct kunit *test) +{ + KUNIT_START_SUPPRESSED_WARNING(test); + trigger_backtrace_warn(); + KUNIT_END_SUPPRESSED_WARNING(test); + + KUNIT_EXPECT_SUPPRESSED_WARNING_COUNT(test, 1); +} + +static void backtrace_suppression_test_warn_multi(struct kunit *test) +{ + KUNIT_START_SUPPRESSED_WARNING(test); + WARN(1, "This backtrace should be suppressed"); + trigger_backtrace_warn(); + KUNIT_END_SUPPRESSED_WARNING(test); + + KUNIT_EXPECT_SUPPRESSED_WARNING_COUNT(test, 2); +} + +static void backtrace_suppression_test_warn_on_direct(struct kunit *test) +{ + if (!IS_ENABLED(CONFIG_DEBUG_BUGVERBOSE) && !IS_ENABLED(CONFIG_KALLSYMS)) + kunit_skip(test, "requires CONFIG_DEBUG_BUGVERBOSE or CONFIG_KALLSYMS"); + + KUNIT_START_SUPPRESSED_WARNING(test); + WARN_ON(1); + KUNIT_END_SUPPRESSED_WARNING(test); + + KUNIT_EXPECT_SUPPRESSED_WARNING_COUNT(test, 1); +} + +static void trigger_backtrace_warn_on(void) +{ + WARN_ON(1); +} + +static void backtrace_suppression_test_warn_on_indirect(struct kunit *test) +{ + if (!IS_ENABLED(CONFIG_DEBUG_BUGVERBOSE)) + kunit_skip(test, "requires CONFIG_DEBUG_BUGVERBOSE"); + + KUNIT_START_SUPPRESSED_WARNING(test); + trigger_backtrace_warn_on(); + KUNIT_END_SUPPRESSED_WARNING(test); + + KUNIT_EXPECT_SUPPRESSED_WARNING_COUNT(test, 1); +} + +static void backtrace_suppression_test_count(struct kunit *test) +{ + KUNIT_START_SUPPRESSED_WARNING(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); + + KUNIT_END_SUPPRESSED_WARNING(test); +} + +static void backtrace_suppression_test_active_state(struct kunit *test) +{ + KUNIT_EXPECT_FALSE(test, kunit_has_active_suppress_warning()); + + KUNIT_START_SUPPRESSED_WARNING(test); + KUNIT_EXPECT_TRUE(test, kunit_has_active_suppress_warning()); + KUNIT_END_SUPPRESSED_WARNING(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()); +} + +static void backtrace_suppression_test_multi_scope(struct kunit *test) +{ + struct kunit_suppressed_warning *sw1, *sw2; + + 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); + return 0; +} + +static void backtrace_suppression_test_cross_kthread(struct kunit *test) +{ + struct cross_kthread_data data; + struct task_struct *task; + + init_completion(&data.done); + + KUNIT_START_SUPPRESSED_WARNING(test); + + task = kthread_run(cross_kthread_fn, &data, "kunit-cross-test"); + KUNIT_ASSERT_FALSE(test, IS_ERR(task)); + wait_for_completion(&data.done); + + KUNIT_END_SUPPRESSED_WARNING(test); + + 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"); -- 2.53.0
