linux-kernel - [PATCH 3/4] locktorture: Cannot hold read and write lock

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Date:	Mon, 29 Sep 2014 06:14:25 -0700
From:	Davidlohr Bueso <dave@...olabs.net>
To:	paulmck@...ux.vnet.ibm.com
Cc:	peterz@...radead.org, mingo@...nel.org, dave@...olabs.net,
	linux-kernel@...r.kernel.org, Davidlohr Bueso <dbueso@...e.de>
Subject: [PATCH 3/4] locktorture: Cannot hold read and write lock

... trigger an error if so.

Signed-off-by: Davidlohr Bueso <dbueso@...e.de>
---
 kernel/locking/locktorture.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/kernel/locking/locktorture.c b/kernel/locking/locktorture.c
index 9e9cd11..b05dc46 100644
--- a/kernel/locking/locktorture.c
+++ b/kernel/locking/locktorture.c
@@ -453,14 +453,19 @@ static int lock_torture_writer(void *arg)
 	do {
 		if ((torture_random(&rand) & 0xfffff) == 0)
 			schedule_timeout_uninterruptible(1);
+
 		cxt.cur_ops->writelock();
 		if (WARN_ON_ONCE(lock_is_write_held))
 			lwsp->n_lock_fail++;
 		lock_is_write_held = 1;
+		if (WARN_ON_ONCE(lock_is_read_held))
+			lwsp->n_lock_fail++; /* rare, but... */
+
 		lwsp->n_lock_acquired++;
 		cxt.cur_ops->write_delay(&rand);
 		lock_is_write_held = 0;
 		cxt.cur_ops->writeunlock();
+
 		stutter_wait("lock_torture_writer");
 	} while (!torture_must_stop());
 	torture_kthread_stopping("lock_torture_writer");
@@ -482,12 +487,17 @@ static int lock_torture_reader(void *arg)
 	do {
 		if ((torture_random(&rand) & 0xfffff) == 0)
 			schedule_timeout_uninterruptible(1);
+
 		cxt.cur_ops->readlock();
 		lock_is_read_held = 1;
+		if (WARN_ON_ONCE(lock_is_write_held))
+			lrsp->n_lock_fail++; /* rare, but... */
+
 		lrsp->n_lock_acquired++;
 		cxt.cur_ops->read_delay(&rand);
 		lock_is_read_held = 0;
 		cxt.cur_ops->readunlock();
+
 		stutter_wait("lock_torture_reader");
 	} while (!torture_must_stop());
 	torture_kthread_stopping("lock_torture_reader");
-- 
1.8.4.5

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