diff --git a/Documentation/RCU/torture.txt b/Documentation/RCU/torture.txt
index 2174bad..2180ef9 100644
--- a/Documentation/RCU/torture.txt
+++ b/Documentation/RCU/torture.txt
@@ -28,6 +28,15 @@
 		To properly exercise RCU implementations with preemptible
 		read-side critical sections.
 
+nfakewriters	This is the number of RCU fake writer threads to run.  Fake
+		writer threads repeatedly use the synchronous "wait for
+		current readers" function of the interface selected by
+		torture_type, with a delay between calls to allow for various
+		different numbers of writers running in parallel.
+		nfakewriters defaults to 4, which provides enough parallelism
+		to trigger special cases caused by multiple writers, such as
+		the synchronize_srcu() early return optimization.
+
 stat_interval	The number of seconds between output of torture
 		statistics (via printk()).  Regardless of the interval,
 		statistics are printed when the module is unloaded.
diff --git a/kernel/rcutorture.c b/kernel/rcutorture.c
index 43d6d4f..e045021 100644
--- a/kernel/rcutorture.c
+++ b/kernel/rcutorture.c
@@ -15,9 +15,10 @@
  * along with this program; if not, write to the Free Software
  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  *
- * Copyright (C) IBM Corporation, 2005
+ * Copyright (C) IBM Corporation, 2005, 2006
  *
  * Authors: Paul E. McKenney <paulmck@us.ibm.com>
+ *          Josh Triplett <josh@freedesktop.org>
  *
  * See also:  Documentation/RCU/torture.txt
  */
@@ -47,9 +48,11 @@
 #include <linux/srcu.h>
 
 MODULE_LICENSE("GPL");
-MODULE_AUTHOR("Paul E. McKenney <paulmck@us.ibm.com>");
+MODULE_AUTHOR("Paul E. McKenney <paulmck@us.ibm.com> and "
+              "Josh Triplett <josh@freedesktop.org>");
 
 static int nreaders = -1;	/* # reader threads, defaults to 2*ncpus */
+static int nfakewriters = 4;	/* # fake writer threads */
 static int stat_interval;	/* Interval between stats, in seconds. */
 				/*  Defaults to "only at end of test". */
 static int verbose;		/* Print more debug info. */
@@ -59,6 +62,8 @@
 
 module_param(nreaders, int, 0);
 MODULE_PARM_DESC(nreaders, "Number of RCU reader threads");
+module_param(nfakewriters, int, 0);
+MODULE_PARM_DESC(nfakewriters, "Number of RCU fake writer threads");
 module_param(stat_interval, int, 0);
 MODULE_PARM_DESC(stat_interval, "Number of seconds between stats printk()s");
 module_param(verbose, bool, 0);
@@ -82,6 +87,7 @@
 
 static int nrealreaders;
 static struct task_struct *writer_task;
+static struct task_struct **fakewriter_tasks;
 static struct task_struct **reader_tasks;
 static struct task_struct *stats_task;
 static struct task_struct *shuffler_task;
@@ -186,6 +192,7 @@
 	void (*readunlock)(int idx);
 	int (*completed)(void);
 	void (*deferredfree)(struct rcu_torture *p);
+	void (*sync)(void);
 	int (*stats)(char *page);
 	char *name;
 };
@@ -258,6 +265,7 @@
 	.readunlock = rcu_torture_read_unlock,
 	.completed = rcu_torture_completed,
 	.deferredfree = rcu_torture_deferred_free,
+	.sync = synchronize_rcu,
 	.stats = NULL,
 	.name = "rcu"
 };
@@ -287,6 +295,28 @@
 	call_rcu_bh(&p->rtort_rcu, rcu_torture_cb);
 }
 
+struct rcu_bh_torture_synchronize {
+	struct rcu_head head;
+	struct completion completion;
+};
+
+static void rcu_bh_torture_wakeme_after_cb(struct rcu_head *head)
+{
+	struct rcu_bh_torture_synchronize *rcu;
+
+	rcu = container_of(head, struct rcu_bh_torture_synchronize, head);
+	complete(&rcu->completion);
+}
+
+static void rcu_bh_torture_synchronize(void)
+{
+	struct rcu_bh_torture_synchronize rcu;
+
+	init_completion(&rcu.completion);
+	call_rcu_bh(&rcu.head, rcu_bh_torture_wakeme_after_cb);
+	wait_for_completion(&rcu.completion);
+}
+
 static struct rcu_torture_ops rcu_bh_ops = {
 	.init = NULL,
 	.cleanup = NULL,
@@ -295,6 +325,7 @@
 	.readunlock = rcu_bh_torture_read_unlock,
 	.completed = rcu_bh_torture_completed,
 	.deferredfree = rcu_bh_torture_deferred_free,
+	.sync = rcu_bh_torture_synchronize,
 	.stats = NULL,
 	.name = "rcu_bh"
 };
@@ -367,6 +398,11 @@
 	}
 }
 
+static void srcu_torture_synchronize(void)
+{
+	synchronize_srcu(&srcu_ctl);
+}
+
 static int srcu_torture_stats(char *page)
 {
 	int cnt = 0;
@@ -392,6 +428,7 @@
 	.readunlock = srcu_torture_read_unlock,
 	.completed = srcu_torture_completed,
 	.deferredfree = srcu_torture_deferred_free,
+	.sync = srcu_torture_synchronize,
 	.stats = srcu_torture_stats,
 	.name = "srcu"
 };
@@ -444,6 +481,30 @@
 }
 
 /*
+ * RCU torture fake writer kthread.  Repeatedly calls sync, with a random
+ * delay between calls.
+ */
+static int
+rcu_torture_fakewriter(void *arg)
+{
+	DEFINE_RCU_RANDOM(rand);
+
+	VERBOSE_PRINTK_STRING("rcu_torture_fakewriter task started");
+	set_user_nice(current, 19);
+
+	do {
+		schedule_timeout_uninterruptible(1 + rcu_random(&rand)%10);
+		udelay(rcu_random(&rand) & 0x3ff);
+		cur_ops->sync();
+	} while (!kthread_should_stop() && !fullstop);
+
+	VERBOSE_PRINTK_STRING("rcu_torture_fakewriter task stopping");
+	while (!kthread_should_stop())
+		schedule_timeout_uninterruptible(1);
+	return 0;
+}
+
+/*
  * RCU torture reader kthread.  Repeatedly dereferences rcu_torture_current,
  * incrementing the corresponding element of the pipeline array.  The
  * counter in the element should never be greater than 1, otherwise, the
@@ -621,6 +682,12 @@
 				set_cpus_allowed(reader_tasks[i], tmp_mask);
 	}
 
+	if (fakewriter_tasks != NULL) {
+		for (i = 0; i < nfakewriters; i++)
+			if (fakewriter_tasks[i])
+				set_cpus_allowed(fakewriter_tasks[i], tmp_mask);
+	}
+
 	if (writer_task)
 		set_cpus_allowed(writer_task, tmp_mask);
 
@@ -654,11 +721,12 @@
 static inline void
 rcu_torture_print_module_parms(char *tag)
 {
-	printk(KERN_ALERT "%s" TORTURE_FLAG "--- %s: nreaders=%d "
+	printk(KERN_ALERT "%s" TORTURE_FLAG
+		"--- %s: nreaders=%d nfakewriters=%d "
 		"stat_interval=%d verbose=%d test_no_idle_hz=%d "
 		"shuffle_interval = %d\n",
-		torture_type, tag, nrealreaders, stat_interval, verbose,
-		test_no_idle_hz, shuffle_interval);
+		torture_type, tag, nrealreaders, nfakewriters,
+		stat_interval, verbose, test_no_idle_hz, shuffle_interval);
 }
 
 static void
@@ -693,6 +761,19 @@
 	}
 	rcu_torture_current = NULL;
 
+	if (fakewriter_tasks != NULL) {
+		for (i = 0; i < nfakewriters; i++) {
+			if (fakewriter_tasks[i] != NULL) {
+				VERBOSE_PRINTK_STRING(
+					"Stopping rcu_torture_fakewriter task");
+				kthread_stop(fakewriter_tasks[i]);
+			}
+			fakewriter_tasks[i] = NULL;
+		}
+		kfree(fakewriter_tasks);
+		fakewriter_tasks = NULL;
+	}
+
 	if (stats_task != NULL) {
 		VERBOSE_PRINTK_STRING("Stopping rcu_torture_stats task");
 		kthread_stop(stats_task);
@@ -780,6 +861,24 @@
 		writer_task = NULL;
 		goto unwind;
 	}
+	fakewriter_tasks = kzalloc(nfakewriters * sizeof(fakewriter_tasks[0]),
+	                           GFP_KERNEL);
+	if (fakewriter_tasks == NULL) {
+		VERBOSE_PRINTK_ERRSTRING("out of memory");
+		firsterr = -ENOMEM;
+		goto unwind;
+	}
+	for (i = 0; i < nfakewriters; i++) {
+		VERBOSE_PRINTK_STRING("Creating rcu_torture_fakewriter task");
+		fakewriter_tasks[i] = kthread_run(rcu_torture_fakewriter, NULL,
+		                                  "rcu_torture_fakewriter");
+		if (IS_ERR(fakewriter_tasks[i])) {
+			firsterr = PTR_ERR(fakewriter_tasks[i]);
+			VERBOSE_PRINTK_ERRSTRING("Failed to create fakewriter");
+			fakewriter_tasks[i] = NULL;
+			goto unwind;
+		}
+	}
 	reader_tasks = kzalloc(nrealreaders * sizeof(reader_tasks[0]),
 			       GFP_KERNEL);
 	if (reader_tasks == NULL) {