[PATCH tip/core/rcu 03/28] locktorture: Track time of last ->writeunlock()

paulmck
2020-11-05T23:49:07Z

This commit adds a last_lock_release variable that tracks the time of
the last ->writeunlock() call, which allows easier diagnosing of lock
hangs when using a kernel debugger.

Cc: Davidlohr Bueso <dave@stgolabs.net>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
---
kernel/locking/locktorture.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/kernel/locking/locktorture.c b/kernel/locking/locktorture.c
index 62d215b..316531d 100644
--- a/kernel/locking/locktorture.c
+++ b/kernel/locking/locktorture.c
@@ -60,6 +60,7 @@ static struct task_struct **reader_tasks;

static bool lock_is_write_held;
static bool lock_is_read_held;
+static unsigned long last_lock_release;

struct lock_stress_stats {
long n_lock_fail;
@@ -632,6 +633,7 @@ static int lock_torture_writer(void *arg)
lwsp->n_lock_acquired++;
cxt.cur_ops->write_delay(&rand);
lock_is_write_held = false;
+ WRITE_ONCE(last_lock_release, jiffies);
cxt.cur_ops->writeunlock();

stutter_wait("lock_torture_writer");
--
2.9.5