diff --git a/kernel/rcu/rcu.h b/kernel/rcu/rcu.h
index 2909662..dfcec92 100644
--- a/kernel/rcu/rcu.h
+++ b/kernel/rcu/rcu.h
@@ -590,6 +590,8 @@ void do_trace_rcu_torture_read(const char *rcutorturename,
 #endif
 static inline void rcu_gp_set_torture_wait(int duration) { }
 #endif
+unsigned long rcutorture_gather_gp_seqs(void);
+void rcutorture_format_gp_seqs(unsigned long seqs, char *cp);
 
 #ifdef CONFIG_TINY_SRCU
 
diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
index ed78b90..30ad675 100644
--- a/kernel/rcu/rcutorture.c
+++ b/kernel/rcu/rcutorture.c
@@ -273,6 +273,8 @@ struct rt_read_seg {
 	bool rt_preempted;
 	int rt_cpu;
 	int rt_end_cpu;
+	unsigned long rt_gp_seq;
+	unsigned long rt_gp_seq_end;
 };
 static int err_segs_recorded;
 static struct rt_read_seg err_segs[RCUTORTURE_RDR_MAX_SEGS];
@@ -407,6 +409,8 @@ struct rcu_torture_ops {
 	void (*gp_slow_register)(atomic_t *rgssp);
 	void (*gp_slow_unregister)(atomic_t *rgssp);
 	bool (*reader_blocked)(void);
+	unsigned long (*gather_gp_seqs)(void);
+	void (*format_gp_seqs)(unsigned long seqs, char *cp);
 	long cbflood_max;
 	int irq_capable;
 	int can_boost;
@@ -611,6 +615,8 @@ static struct rcu_torture_ops rcu_ops = {
 	.reader_blocked		= IS_ENABLED(CONFIG_RCU_TORTURE_TEST_LOG_CPU)
 				  ? has_rcu_reader_blocked
 				  : NULL,
+	.gather_gp_seqs		= rcutorture_gather_gp_seqs,
+	.format_gp_seqs		= rcutorture_format_gp_seqs,
 	.irq_capable		= 1,
 	.can_boost		= IS_ENABLED(CONFIG_RCU_BOOST),
 	.extendables		= RCUTORTURE_MAX_EXTEND,
@@ -656,6 +662,8 @@ static struct rcu_torture_ops rcu_busted_ops = {
 	.sync		= synchronize_rcu_busted,
 	.exp_sync	= synchronize_rcu_busted,
 	.call		= call_rcu_busted,
+	.gather_gp_seqs	= rcutorture_gather_gp_seqs,
+	.format_gp_seqs	= rcutorture_format_gp_seqs,
 	.irq_capable	= 1,
 	.extendables	= RCUTORTURE_MAX_EXTEND,
 	.name		= "busted"
@@ -1989,6 +1997,12 @@ static void rcutorture_one_extend(int *readstate, int newstate, bool insoftirq,
 				rtrsp[-1].rt_preempted = cur_ops->reader_blocked();
 		}
 	}
+	// Sample grace-period sequence number, as good a place as any.
+	if (cur_ops->gather_gp_seqs) {
+		rtrsp->rt_gp_seq = cur_ops->gather_gp_seqs();
+		if (!first)
+			rtrsp[-1].rt_gp_seq_end = rtrsp->rt_gp_seq;
+	}
 
 	/*
 	 * Next, remove old protection, in decreasing order of strength
@@ -3569,6 +3583,7 @@ rcu_torture_cleanup(void)
 	int flags = 0;
 	unsigned long gp_seq = 0;
 	int i;
+	int j;
 
 	if (torture_cleanup_begin()) {
 		if (cur_ops->cb_barrier != NULL) {
@@ -3664,6 +3679,24 @@ rcu_torture_cleanup(void)
 				else
 					pr_cont(" ...");
 			}
+			if (cur_ops->gather_gp_seqs && cur_ops->format_gp_seqs) {
+				char buf1[16+1];
+				char buf2[16+1];
+				char sepchar = '-';
+
+				cur_ops->format_gp_seqs(err_segs[i].rt_gp_seq, buf1);
+				cur_ops->format_gp_seqs(err_segs[i].rt_gp_seq_end, buf2);
+				if (err_segs[i].rt_gp_seq == err_segs[i].rt_gp_seq_end) {
+					if (buf2[0]) {
+						for (j = 0; buf2[j]; j++)
+							buf2[j] = '.';
+						if (j)
+							buf2[j - 1] = ' ';
+					}
+					sepchar = ' ';
+				}
+				pr_cont(" %s%c%s", buf1, sepchar, buf2);
+			}
 			if (err_segs[i].rt_delay_ms != 0) {
 				pr_cont(" %s%ldms", firsttime ? "" : "+",
 					err_segs[i].rt_delay_ms);
diff --git a/kernel/rcu/tiny.c b/kernel/rcu/tiny.c
index b3b3ce34..f068bd9 100644
--- a/kernel/rcu/tiny.c
+++ b/kernel/rcu/tiny.c
@@ -257,6 +257,20 @@ void kvfree_call_rcu(struct rcu_head *head, void *ptr)
 EXPORT_SYMBOL_GPL(kvfree_call_rcu);
 #endif
 
+#ifdef CONFIG_RCU_TORTURE_TEST
+unsigned long rcutorture_gather_gp_seqs(void)
+{
+	return READ_ONCE(rcu_ctrlblk.gp_seq) & 0xff;
+}
+EXPORT_SYMBOL_GPL(rcutorture_gather_gp_seqs);
+
+void rcutorture_format_gp_seqs(unsigned long seqs, char *cp)
+{
+	snprintf(cp, 8, "g%02lx", seqs & 0xff);
+}
+EXPORT_SYMBOL_GPL(rcutorture_format_gp_seqs);
+#endif
+
 void __init rcu_init(void)
 {
 	open_softirq(RCU_SOFTIRQ, rcu_process_callbacks);
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 976b317..aeceac2 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -559,6 +559,26 @@ void rcutorture_get_gp_data(int *flags, unsigned long *gp_seq)
 }
 EXPORT_SYMBOL_GPL(rcutorture_get_gp_data);
 
+/* Gather grace-period sequence numbers for rcutorture diagnostics. */
+unsigned long rcutorture_gather_gp_seqs(void)
+{
+	return ((READ_ONCE(rcu_state.gp_seq) & 0xff) << 16) |
+	       ((READ_ONCE(rcu_state.expedited_sequence) & 0xff) << 8) |
+	       (READ_ONCE(rcu_state.gp_seq_polled) & 0xff);
+}
+EXPORT_SYMBOL_GPL(rcutorture_gather_gp_seqs);
+
+/* Format grace-period sequence numbers for rcutorture diagnostics. */
+void rcutorture_format_gp_seqs(unsigned long seqs, char *cp)
+{
+	unsigned int egp = (seqs >> 8) & 0xff;
+	unsigned int ggp = (seqs >> 16) & 0xff;
+	unsigned int pgp = seqs & 0xff;
+
+	snprintf(cp, 16, "g%02x:e%02x:p%02x", ggp, egp, pgp);
+}
+EXPORT_SYMBOL_GPL(rcutorture_format_gp_seqs);
+
 #if defined(CONFIG_NO_HZ_FULL) && (!defined(CONFIG_GENERIC_ENTRY) || !defined(CONFIG_KVM_XFER_TO_GUEST_WORK))
 /*
  * An empty function that will trigger a reschedule on