[Bug] ARM: mxs: STI: console can't wake up from freeze
Zhang Rui
rui.zhang at intel.com
Sat Nov 5 04:39:32 PDT 2016
On Sat, 2016-11-05 at 12:07 +0100, Stefan Wahren wrote:
> Hi,
>
> [add Rui]
>
> >
> > Russell King - ARM Linux <linux at armlinux.org.uk> hat am 1. November
> > 2016 um
> > 10:23 geschrieben:
> >
> >
> > On Mon, Oct 31, 2016 at 08:54:33PM +0100, Stefan Wahren wrote:
> > >
> > > [ 366.696043] INFO: task ext4lazyinit:70 blocked for more than
> > > 120 seconds.
> > > [ 366.703046] Not tainted 4.9.0-rc1 #7
> > > [ 366.707188] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs"
> > > disables
> > > this
> > > message.
> > > [ 366.715161] ext4lazyinit D c05aa6ac 0 70 2
> > > 0x00000000
> > This looks like a very different problem - I guess one for ext4
> > people.
> >
> i investigated the issue more further. This trace wasn't
> representative, because
> the stacktrace is different in most cases. The "endless loop" is
> located in
> freeze_enter(). So i added some debug messages:
>
is this a regression?
> -------------------------------->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
>
> >
> > >
> > > >
> > > > 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)
>
> >
> > > > > no reaction to Debug UART
Then the system does not have any response? or the system freezes and
wakes up as expected?
> I expected that in all 3 cases freeze_wake() will be called. Why not?
>
> Here my config again:
>
> CONFIG_PM_SLEEP=y
> CONFIG_SUSPEND=y
> CONFIG_SUSPEND_FREEZER=y
> CONFIG_PM=y
> CONFIG_CPU_IDLE is not set
hmmm, why not have CONFIG_CPU_IDLE set?
thanks,
rui
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