rcutorture: Include grace-period sequence numbers in failure/close-call
This commit includes the grace-period sequence numbers at the beginning
and end of each segment in the "Failure/close-call rcutorture reader
segments" list. These are in hexadecimal, and only the bottom byte.
Currently, only RCU is supported, with its three sequence numbers (normal,
expedited, and polled).
Note that if all the grace-period sequence numbers remain the same across
a given reader segement, only one copy of the number will be printed.
Of course, if there is a change, both sets of values will be printed.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
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
