-------------------------------->8-----------------------------------
-

diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c
index 1e7f5da..079c08d 100644
--- a/kernel/power/suspend.c
+++ b/kernel/power/suspend.c

@@ -67,17 +67,20 @@ static void freeze_enter(void)

?	spin_unlock_irq(&suspend_freeze_lock);
?
?	get_online_cpus();
+	pr_info("PM: calling cpuidle_resume()\n");
?	cpuidle_resume();
?
?	/* Push all the CPUs into the idle loop. */
+	pr_info("PM: calling wake_up_all_idle_cpus()\n");
?	wake_up_all_idle_cpus();
-	pr_debug("PM: suspend-to-idle\n");
+	pr_info("PM: suspend-to-idle\n");
?	/* Make the current CPU wait so it can enter the idle loop
too. */
?	wait_event(suspend_freeze_wait_head,
?		???suspend_freeze_state == FREEZE_STATE_WAKE);
-	pr_debug("PM: resume from suspend-to-idle\n");
+	pr_info("PM: resume from suspend-to-idle\n");
?
?	cpuidle_pause();
+	pr_info("PM: called cpuidle_pause()\n");
?	put_online_cpus();
?
?	spin_lock_irq(&suspend_freeze_lock);

@@ -91,6 +94,8 @@ void freeze_wake(void)

?{
?	unsigned long flags;
?
+	pr_info("PM: freeze_wake()\n");
+
?	spin_lock_irqsave(&suspend_freeze_lock, flags);
?	if (suspend_freeze_state > FREEZE_STATE_NONE) {
?		suspend_freeze_state = FREEZE_STATE_WAKE;

-------------------------------->8-----------------------------------
-

and repeated the test cases for freeze which shows none the
representative
stacktraces:

1. cmdline contains no_console_suspend

* echo freeze > /sys/power/state

...
[??139.371308] PM: suspend of devices complete after 1342.721 msecs
[??139.385203] PM: late suspend of devices complete after 7.668 msecs
[??139.399428] PM: noirq suspend of devices complete after 7.936
msecs
[??139.406639] PM: calling cpuidle_resume()
[??139.410619] PM: calling wake_up_all_idle_cpus()
[??139.415339] PM: suspend-to-idle

quoted

quoted

quoted

no reaction to input via Debug UART

[??366.683570] INFO: task bash:373 blocked for more than 120 seconds.
[??366.689814]???????Not tainted 4.9.0-rc1-dirty #14
[??366.694705] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs"
disables this
message.
[??366.702685] bash????????????D c05aa6ec?????0???373????275
0x00000000
[??366.709227] [<c05aa6ec>] (__schedule) from [<c05aaff8>]
(schedule+0x3c/0xbc)
[??366.716495] [<c05aaff8>] (schedule) from [<c005b588>]
(suspend_devices_and_enter+0x888/0xa78)
[??366.725228] [<c005b588>] (suspend_devices_and_enter) from
[<c005bea4>]
(pm_suspend+0x72c/0x81c)
[??366.734150] [<c005bea4>] (pm_suspend) from [<c005a008>]
(state_store+0x80/0xcc)
[??366.741554] [<c005a008>] (state_store) from [<c02f0270>]
(kobj_attr_store+0x18/0x1c)
[??366.749515] [<c02f0270>] (kobj_attr_store) from [<c01911e8>]
(sysfs_kf_write+0x48/0x4c)
[??366.757735] [<c01911e8>] (sysfs_kf_write) from [<c0190308>]
(kernfs_fop_write+0xfc/0x1d0)
[??366.766130] [<c0190308>] (kernfs_fop_write) from [<c011f578>]
(__vfs_write+0x2c/0x124)
[??366.774255] [<c011f578>] (__vfs_write) from [<c011f724>]
(vfs_write+0xb4/0x1a4)
[??366.781640] [<c011f724>] (vfs_write) from [<c011f8e8>]
(SyS_write+0x44/0x88)
[??366.788890] [<c011f8e8>] (SyS_write) from [<c000a2c0>]
(ret_fast_syscall+0x0/0x1c)
[??366.796627]
[??366.796627] Showing all locks held in the system:
[??366.803011] 2 locks held by khungtaskd/10:
[??366.807149]??#0: [??366.808931]??(
rcu_read_lock[??366.811784] ){......}
, at: [??366.814813] [<c0093a40>] watchdog+0xb4/0x61c
[??366.819128]??#1: [??366.820902]??(
tasklist_lock[??366.823876] ){.+.+..}
, at: [??366.826765] [<c0051dbc>] debug_show_all_locks+0x28/0x1bc
[??366.832151] 4 locks held by bash/373:
[??366.835973]??#0: [??366.837765]??(
sb_writers[??366.840365] #4
){.+.+.+}[??366.842987] , at:
[??366.845079] [<c011f804>] vfs_write+0x194/0x1a4
[??366.849551]??#1: [??366.851324]??(
&of->mutex[??366.854058] ){+.+.+.}
, at: [??366.856944] [<c01902cc>] kernfs_fop_write+0xc0/0x1d0
[??366.861941]??#2: [??366.863839]??(
s_active[??366.866288] #43
){.+.+.+}[??366.868877] , at:
[??366.870938] [<c01902d4>] kernfs_fop_write+0xc8/0x1d0
[??366.876053]??#3: [??366.877843]??(
pm_mutex[??366.880272] ){+.+.+.}
, at: [??366.883266] [<c005b808>] pm_suspend+0x90/0x81c
[??366.887757]
[??366.889268] =============================================
[??366.889268]

2. cmdline contains no_console_suspend

* echo enabled > /sys/class/tty/ttyAMA0/power/wakeup
* echo freeze > /sys/power/state

the same as in 1.

3. cmdline doesn't contains no_console_suspend

* echo enabled > /sys/class/tty/ttyAMA0/power/wakeup
* echo freeze > /sys/power/state

[??161.093187] PM: Syncing filesystems ... [??161.734413] done.
[??161.793242] Freezing user space processes ... (elapsed 0.008
seconds) done.
[??161.809797] Freezing remaining freezable tasks ... (elapsed 0.004
seconds)
done.
[??161.821953] Suspending console(s) (use no_console_suspend to
debug)

quoted

?

quoted

quoted

quoted

no reaction to Debug UART