1 files changed, 13 insertions, 4 deletions

diff --git a/kernel/rcutorture.c b/kernel/rcutorture.c
index 2e2726d790b9..9d8e8fb2515f 100644
--- a/kernel/rcutorture.c
+++ b/kernel/rcutorture.c
@@ -120,7 +120,7 @@ struct rcu_torture {
 };
 
 static LIST_HEAD(rcu_torture_freelist);
-static struct rcu_torture *rcu_torture_current;
+static struct rcu_torture __rcu *rcu_torture_current;
 static long rcu_torture_current_version;
 static struct rcu_torture rcu_tortures[10 * RCU_TORTURE_PIPE_LEN];
 static DEFINE_SPINLOCK(rcu_torture_lock);
@@ -153,8 +153,10 @@ int rcutorture_runnable = RCUTORTURE_RUNNABLE_INIT;
 #define FULLSTOP_SHUTDOWN 1     /* System shutdown with rcutorture running. */
 #define FULLSTOP_RMMOD    2     /* Normal rmmod of rcutorture. */
 static int fullstop = FULLSTOP_RMMOD;
-DEFINE_MUTEX(fullstop_mutex);   /* Protect fullstop transitions and spawning */
-                                /*  of kthreads. */
+/*
+ * Protect fullstop transitions and spawning of kthreads.
+ */
+static DEFINE_MUTEX(fullstop_mutex);
 
 /*
  * Detect and respond to a system shutdown.
@@ -303,6 +305,10 @@ static void rcu_read_delay(struct rcu_random_state *rrsp)
                 mdelay(longdelay_ms);
         if (!(rcu_random(rrsp) % (nrealreaders * 2 * shortdelay_us)))
                 udelay(shortdelay_us);
+#ifdef CONFIG_PREEMPT
+        if (!preempt_count() && !(rcu_random(rrsp) % (nrealreaders * 20000)))
+                preempt_schedule();  /* No QS if preempt_disable() in effect */
+#endif
 }
 
 static void rcu_torture_read_unlock(int idx) __releases(RCU)
@@ -536,6 +542,8 @@ static void srcu_read_delay(struct rcu_random_state *rrsp)
         delay = rcu_random(rrsp) % (nrealreaders * 2 * longdelay * uspertick);
         if (!delay)
                 schedule_timeout_interruptible(longdelay);
+        else
+                rcu_read_delay(rrsp);
 }
 
 static void srcu_torture_read_unlock(int idx) __releases(&srcu_ctl)
@@ -731,7 +739,8 @@ rcu_torture_writer(void *arg)
                         continue;
                 rp->rtort_pipe_count = 0;
                 udelay(rcu_random(&rand) & 0x3ff);
-                old_rp = rcu_torture_current;
+                old_rp = rcu_dereference_check(rcu_torture_current,
+                                               current == writer_task);
                 rp->rtort_mbtest = 1;
                 rcu_assign_pointer(rcu_torture_current, rp);
                 smp_wmb(); /* Mods to old_rp must follow rcu_assign_pointer() */