Torture-test update for v4.15

index 45f2ffbc1e78..0273bc0a8586 100644
@@ -89,6 +89,7 @@ torture_param(int, shutdown_secs, 0, "Shutdown time (s), <= zero to disable.");
 torture_param(int, stall_cpu, 0, "Stall duration (s), zero to disable.");
 torture_param(int, stall_cpu_holdoff, 10,
 	     "Time to wait before starting stall (s).");
+torture_param(int, stall_cpu_irqsoff, 0, "Disable interrupts while stalling.");
 torture_param(int, stat_interval, 60,
 	     "Number of seconds between stats printk()s");
 torture_param(int, stutter, 5, "Number of seconds to run/halt test");

@@ -1357,7 +1358,7 @@ rcu_torture_print_module_parms(struct rcu_torture_ops *cur_ops, const char *tag)
 		 "fqs_duration=%d fqs_holdoff=%d fqs_stutter=%d "
 		 "test_boost=%d/%d test_boost_interval=%d "
 		 "test_boost_duration=%d shutdown_secs=%d "
-		 "stall_cpu=%d stall_cpu_holdoff=%d "
+		 "stall_cpu=%d stall_cpu_holdoff=%d stall_cpu_irqsoff=%d "
 		 "n_barrier_cbs=%d "
 		 "onoff_interval=%d onoff_holdoff=%d\n",
 		 torture_type, tag, nrealreaders, nfakewriters,

@@ -1365,7 +1366,7 @@ rcu_torture_print_module_parms(struct rcu_torture_ops *cur_ops, const char *tag)
 		 stutter, irqreader, fqs_duration, fqs_holdoff, fqs_stutter,
 		 test_boost, cur_ops->can_boost,
 		 test_boost_interval, test_boost_duration, shutdown_secs,
-		 stall_cpu, stall_cpu_holdoff,
+		 stall_cpu, stall_cpu_holdoff, stall_cpu_irqsoff,
 		 n_barrier_cbs,
 		 onoff_interval, onoff_holdoff);
 }

@@ -1430,12 +1431,19 @@ static int rcu_torture_stall(void *args)
 	if (!kthread_should_stop()) {
 		stop_at = get_seconds() + stall_cpu;
 		/* RCU CPU stall is expected behavior in following code. */
-		pr_alert("rcu_torture_stall start.\n");
 		rcu_read_lock();
-		preempt_disable();
+		if (stall_cpu_irqsoff)
+			local_irq_disable();
+		else
+			preempt_disable();
+		pr_alert("rcu_torture_stall start on CPU %d.\n",
+			 smp_processor_id());
 		while (ULONG_CMP_LT(get_seconds(), stop_at))
 			continue;  /* Induce RCU CPU stall warning. */
-		preempt_enable();
+		if (stall_cpu_irqsoff)
+			local_irq_enable();
+		else
+			preempt_enable();
 		rcu_read_unlock();
 		pr_alert("rcu_torture_stall end.\n");
 	}

index 0273bc0a8586..362eb2f78b3c 100644
@@ -51,6 +51,7 @@
 #include <asm/byteorder.h>
 #include <linux/torture.h>
 #include <linux/vmalloc.h>
+#include <linux/sched/debug.h>
 
 #include "rcu.h"
 

@@ -1240,6 +1241,7 @@ rcu_torture_stats_print(void)
 	long pipesummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
 	long batchsummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
 	static unsigned long rtcv_snap = ULONG_MAX;
+	static bool splatted;
 	struct task_struct *wtp;
 
 	for_each_possible_cpu(cpu) {

@@ -1325,6 +1327,10 @@ rcu_torture_stats_print(void)
 			 gpnum, completed, flags,
 			 wtp == NULL ? ~0UL : wtp->state,
 			 wtp == NULL ? -1 : (int)task_cpu(wtp));
+		if (!splatted && wtp) {
+			sched_show_task(wtp);
+			splatted = true;
+		}
 		show_rcu_gp_kthreads();
 		rcu_ftrace_dump(DUMP_ALL);
 	}

index d17c5da523a0..7ae0151dcc1d 100644
@@ -5165,6 +5165,7 @@ void sched_show_task(struct task_struct *p)
 	show_stack(p, NULL);
 	put_task_stack(p);
 }
+EXPORT_SYMBOL_GPL(sched_show_task);
 
 static inline bool
 state_filter_match(unsigned long state_filter, struct task_struct *p)