Commit fda5ba9e authored by Paul E. McKenney's avatar Paul E. McKenney
Browse files

torture: Make torture_stutter() use hrtimer 



The torture_stutter() function uses schedule_timeout_interruptible()
to time the stutter duration, but this can miss race conditions due to
its being time-synchronized with everything else that is based on the
timer wheels.  This commit therefore converts torture_stutter() to use
the high-resolution timers via schedule_hrtimeout(), and also to fuzz
the stutter interval.  While in the area, this commit also limits the
spin-loop portion of the stutter_wait() function's wait loop to two
jiffies, down from about one second.

Signed-off-by: default avatarPaul E. McKenney <paulmck@kernel.org>
parent 19012b78

kernel/torture.c

+12 −5
Original line number Diff line number Diff line
@@ -641,20 +641,27 @@ EXPORT_SYMBOL_GPL(stutter_wait); 
 */

static int torture_stutter(void *arg)

{

	ktime_t delay;

	DEFINE_TORTURE_RANDOM(rand);

	int wtime;



	VERBOSE_TOROUT_STRING("torture_stutter task started");

	do {

		if (!torture_must_stop() && stutter > 1) {

			wtime = stutter;

			if (stutter > HZ + 1) {

			if (stutter > 2) {

				WRITE_ONCE(stutter_pause_test, 1);

				wtime = stutter - HZ - 1;

				schedule_timeout_interruptible(wtime);

				wtime = HZ + 1;

				wtime = stutter - 3;

				delay = ktime_divns(NSEC_PER_SEC * wtime, HZ);

				delay += (torture_random(&rand) >> 3) % NSEC_PER_MSEC;

				set_current_state(TASK_INTERRUPTIBLE);

				schedule_hrtimeout(&delay, HRTIMER_MODE_REL);

				wtime = 2;

			}

			WRITE_ONCE(stutter_pause_test, 2);

			schedule_timeout_interruptible(wtime);

			delay = ktime_divns(NSEC_PER_SEC * wtime, HZ);

			set_current_state(TASK_INTERRUPTIBLE);

			schedule_hrtimeout(&delay, HRTIMER_MODE_REL);

		}

		WRITE_ONCE(stutter_pause_test, 0);

		if (!torture_must_stop())