Commit-ID: 70207686e492fb97c11d88ae7d8ebce7d2d080aa
Gitweb: http://git.kernel.org/tip/70207686e492fb97c11d88ae7d8ebce7d2d080aa
Author: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
AuthorDate: Thu, 1 Dec 2016 11:47:08 +0000
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Sat, 14 Jan 2017 11:37:16 +0100
locking/ww_mutex: Add kselftests for ww_mutex ABBA deadlock detection
Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Maarten Lankhorst <dev@xxxxxxxxxxxxxx>
Cc: Nicolai Hähnle <nhaehnle@xxxxxxxxx>
Cc: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/20161201114711.28697-6-chris@xxxxxxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
kernel/locking/test-ww_mutex.c | 98 ++++++++++++++++++++++++++++++++++++++++++
1 file changed, 98 insertions(+)
diff --git a/kernel/locking/test-ww_mutex.c b/kernel/locking/test-ww_mutex.c
index 835fa7a..5a643ba 100644
--- a/kernel/locking/test-ww_mutex.c
+++ b/kernel/locking/test-ww_mutex.c
@@ -153,6 +153,96 @@ out:
return ret;
}
+struct test_abba {
+ struct work_struct work;
+ struct ww_mutex a_mutex;
+ struct ww_mutex b_mutex;
+ struct completion a_ready;
+ struct completion b_ready;
+ bool resolve;
+ int result;
+};
+
+static void test_abba_work(struct work_struct *work)
+{
+ struct test_abba *abba = container_of(work, typeof(*abba), work);
+ struct ww_acquire_ctx ctx;
+ int err;
+
+ ww_acquire_init(&ctx, &ww_class);
+ ww_mutex_lock(&abba->b_mutex, &ctx);
+
+ complete(&abba->b_ready);
+ wait_for_completion(&abba->a_ready);
+
+ err = ww_mutex_lock(&abba->a_mutex, &ctx);
+ if (abba->resolve && err == -EDEADLK) {
+ ww_mutex_unlock(&abba->b_mutex);
+ ww_mutex_lock_slow(&abba->a_mutex, &ctx);
+ err = ww_mutex_lock(&abba->b_mutex, &ctx);
+ }
+
+ if (!err)
+ ww_mutex_unlock(&abba->a_mutex);
+ ww_mutex_unlock(&abba->b_mutex);
+ ww_acquire_fini(&ctx);
+
+ abba->result = err;
+}
+
+static int test_abba(bool resolve)
+{
+ struct test_abba abba;
+ struct ww_acquire_ctx ctx;
+ int err, ret;
+
+ ww_mutex_init(&abba.a_mutex, &ww_class);
+ ww_mutex_init(&abba.b_mutex, &ww_class);
+ INIT_WORK_ONSTACK(&abba.work, test_abba_work);
+ init_completion(&abba.a_ready);
+ init_completion(&abba.b_ready);
+ abba.resolve = resolve;
+
+ schedule_work(&abba.work);
+
+ ww_acquire_init(&ctx, &ww_class);
+ ww_mutex_lock(&abba.a_mutex, &ctx);
+
+ complete(&abba.a_ready);
+ wait_for_completion(&abba.b_ready);
+
+ err = ww_mutex_lock(&abba.b_mutex, &ctx);
+ if (resolve && err == -EDEADLK) {
+ ww_mutex_unlock(&abba.a_mutex);
+ ww_mutex_lock_slow(&abba.b_mutex, &ctx);
+ err = ww_mutex_lock(&abba.a_mutex, &ctx);
+ }
+
+ if (!err)
+ ww_mutex_unlock(&abba.b_mutex);
+ ww_mutex_unlock(&abba.a_mutex);
+ ww_acquire_fini(&ctx);
+
+ flush_work(&abba.work);
+ destroy_work_on_stack(&abba.work);
+
+ ret = 0;
+ if (resolve) {
+ if (err || abba.result) {
+ pr_err("%s: failed to resolve ABBA deadlock, A err=%d, B err=%d\n",
+ __func__, err, abba.result);
+ ret = -EINVAL;
+ }
+ } else {
+ if (err != -EDEADLK && abba.result != -EDEADLK) {
+ pr_err("%s: missed ABBA deadlock, A err=%d, B err=%d\n",
+ __func__, err, abba.result);
+ ret = -EINVAL;
+ }
+ }
+ return ret;
+}
+
static int __init test_ww_mutex_init(void)
{
int ret;
@@ -165,6 +255,14 @@ static int __init test_ww_mutex_init(void)
if (ret)
return ret;
+ ret = test_abba(false);
+ if (ret)
+ return ret;
+
+ ret = test_abba(true);
+ if (ret)
+ return ret;
+
return 0;
}
--
To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
|