lkml.org 
[lkml]   [2020]   [Aug]   [12]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH v2] kunit: added lockdep support
Date
KUnit will fail tests upon observing a lockdep failure. Because lockdep
turns itself off after its first failure, only fail the first test and
warn users to not expect any future failures from lockdep.

Similar to lib/locking-selftest [1], we check if the status of
debug_locks has changed after the execution of a test case. However, we
do not reset lockdep afterwards.

Like the locking selftests, we also fix possible preemption count
corruption from lock bugs.

Depends on kunit: support failure from dynamic analysis tools [2]

[1] https://elixir.bootlin.com/linux/v5.7.12/source/lib/locking-selftest.c#L1137

[2] https://lore.kernel.org/linux-kselftest/20200806174326.3577537-1-urielguajardojr@gmail.com/

Signed-off-by: Uriel Guajardo <urielguajardo@google.com>
---
v2 Changes:
- Removed lockdep_reset

- Added warning to users about lockdep shutting off
---
lib/kunit/test.c | 27 ++++++++++++++++++++++++++-
1 file changed, 26 insertions(+), 1 deletion(-)

diff --git a/lib/kunit/test.c b/lib/kunit/test.c
index d8189d827368..7e477482457b 100644
--- a/lib/kunit/test.c
+++ b/lib/kunit/test.c
@@ -11,6 +11,7 @@
#include <linux/kref.h>
#include <linux/sched/debug.h>
#include <linux/sched.h>
+#include <linux/debug_locks.h>

#include "debugfs.h"
#include "string-stream.h"
@@ -22,6 +23,26 @@ void kunit_fail_current_test(void)
kunit_set_failure(current->kunit_test);
}

+static void kunit_check_locking_bugs(struct kunit *test,
+ unsigned long saved_preempt_count,
+ bool saved_debug_locks)
+{
+ preempt_count_set(saved_preempt_count);
+#ifdef CONFIG_TRACE_IRQFLAGS
+ if (softirq_count())
+ current->softirqs_enabled = 0;
+ else
+ current->softirqs_enabled = 1;
+#endif
+#if IS_ENABLED(CONFIG_LOCKDEP)
+ if (saved_debug_locks && !debug_locks) {
+ kunit_set_failure(test);
+ kunit_warn(test, "Dynamic analysis tool failure from LOCKDEP.");
+ kunit_warn(test, "Further tests will have LOCKDEP disabled.");
+ }
+#endif
+}
+
static void kunit_print_tap_version(void)
{
static bool kunit_has_printed_tap_version;
@@ -290,6 +311,9 @@ static void kunit_try_run_case(void *data)
struct kunit_suite *suite = ctx->suite;
struct kunit_case *test_case = ctx->test_case;

+ unsigned long saved_preempt_count = preempt_count();
+ bool saved_debug_locks = debug_locks;
+
current->kunit_test = test;

/*
@@ -298,7 +322,8 @@ static void kunit_try_run_case(void *data)
* thread will resume control and handle any necessary clean up.
*/
kunit_run_case_internal(test, suite, test_case);
- /* This line may never be reached. */
+ /* These lines may never be reached. */
+ kunit_check_locking_bugs(test, saved_preempt_count, saved_debug_locks);
kunit_run_case_cleanup(test, suite);
}

--
2.28.0.236.gb10cc79966-goog
\
 
 \ /
  Last update: 2020-08-12 21:34    [W:0.075 / U:5.024 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site