diff mbox series

[v4] PM / sleep: Mechanism to find source aborting kernel suspend transition

Message ID 20240205170747.19748-1-vimal.kumar32@gmail.com
State New
Headers show
Series [v4] PM / sleep: Mechanism to find source aborting kernel suspend transition | expand

Commit Message

Vimal Kumar Feb. 5, 2024, 5:07 p.m. UTC
Sometimes kernel suspend transitions can be aborted unconditionally by
manipulating pm_abort_suspend value using "hard" wakeup triggers or
through "pm_system_wakeup()".

There is no way to trace the source path of module or subsystem which
aborted the suspend transitions. This change will create a list of
wakeup sources aborting suspend in progress through "hard" events as
well as subsytems aborting suspend using "pm_system_wakeup()".

Example: Existing suspend failure logs:
[  349.708359] PM: Some devices failed to suspend, or early wake event detected
[  350.327842] PM: suspend exit

Suspend failure logs with this change:
[  518.761835] PM: Some devices failed to suspend, or early wake event detected
[  519.486939] PM: wakeup source or subsystem uart_suspend_port aborted suspend
[  519.500594] PM: suspend exit

Here we can clearly identify the module triggerring abort suspend.

Co-developed-by: Chinmoy Ghosh <chinmoyghosh2001@gmail.com>
Signed-off-by: Chinmoy Ghosh <chinmoyghosh2001@gmail.com>
Co-developed-by: Mintu Patel <mintupatel89@gmail.com>
Signed-off-by: Mintu Patel <mintupatel89@gmail.com>
Co-developed-by: Vishal Badole <badolevishal1116@gmail.com>
Signed-off-by: Vishal Badole <badolevishal1116@gmail.com>
Signed-off-by: Vimal Kumar <vimal.kumar32@gmail.com>
---
Changes in v4:
- Changed GFP_KERNEL flag to GFP_ATOMIC
- Changed mutex_lock to raw_spin_lock
---
 drivers/base/power/wakeup.c | 100 +++++++++++++++++++++++++++++++++++-
 1 file changed, 99 insertions(+), 1 deletion(-)

--
2.25.1

Comments

Greg Kroah-Hartman Feb. 5, 2024, 7:33 p.m. UTC | #1
On Mon, Feb 05, 2024 at 10:37:45PM +0530, Vimal Kumar wrote:
> Sometimes kernel suspend transitions can be aborted unconditionally by
> manipulating pm_abort_suspend value using "hard" wakeup triggers or
> through "pm_system_wakeup()".
> 
> There is no way to trace the source path of module or subsystem which
> aborted the suspend transitions. This change will create a list of
> wakeup sources aborting suspend in progress through "hard" events as
> well as subsytems aborting suspend using "pm_system_wakeup()".
> 
> Example: Existing suspend failure logs:
> [  349.708359] PM: Some devices failed to suspend, or early wake event detected
> [  350.327842] PM: suspend exit
> 
> Suspend failure logs with this change:
> [  518.761835] PM: Some devices failed to suspend, or early wake event detected
> [  519.486939] PM: wakeup source or subsystem uart_suspend_port aborted suspend
> [  519.500594] PM: suspend exit
> 
> Here we can clearly identify the module triggerring abort suspend.
> 
> Co-developed-by: Chinmoy Ghosh <chinmoyghosh2001@gmail.com>
> Signed-off-by: Chinmoy Ghosh <chinmoyghosh2001@gmail.com>
> Co-developed-by: Mintu Patel <mintupatel89@gmail.com>
> Signed-off-by: Mintu Patel <mintupatel89@gmail.com>
> Co-developed-by: Vishal Badole <badolevishal1116@gmail.com>
> Signed-off-by: Vishal Badole <badolevishal1116@gmail.com>
> Signed-off-by: Vimal Kumar <vimal.kumar32@gmail.com>
> ---
> Changes in v4:
> - Changed GFP_KERNEL flag to GFP_ATOMIC
> - Changed mutex_lock to raw_spin_lock

why raw?


> ---
>  drivers/base/power/wakeup.c | 100 +++++++++++++++++++++++++++++++++++-
>  1 file changed, 99 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/base/power/wakeup.c b/drivers/base/power/wakeup.c
> index a917219feea6..b04794557eef 100644
> --- a/drivers/base/power/wakeup.c
> +++ b/drivers/base/power/wakeup.c
> @@ -73,6 +73,16 @@ static struct wakeup_source deleted_ws = {
> 
>  static DEFINE_IDA(wakeup_ida);
> 
> +#ifdef CONFIG_PM_DEBUG
> +static DEFINE_RAW_SPINLOCK(pm_abort_suspend_list_lock);
> +
> +struct pm_abort_suspend_source {
> +	struct list_head list;
> +	char *source_triggering_abort_suspend;
> +};
> +static LIST_HEAD(pm_abort_suspend_list);
> +#endif
> +
>  /**
>   * wakeup_source_create - Create a struct wakeup_source object.
>   * @name: Name of the new wakeup source.
> @@ -575,6 +585,54 @@ static void wakeup_source_activate(struct wakeup_source *ws)
> 	trace_wakeup_source_activate(ws->name, cec);
>  }
> 
> +#ifdef CONFIG_PM_DEBUG

Please do not add #ifdef to .c files, this makes this file even messier.

> @@ -590,8 +648,13 @@ static void wakeup_source_report_event(struct wakeup_source *ws, bool hard)
> 	if (!ws->active)
> 		wakeup_source_activate(ws);
> 
> -	if (hard)
> +	if (hard) {
> +#ifdef CONFIG_PM_DEBUG
> +		if (pm_suspend_target_state != PM_SUSPEND_ON)
> +			pm_abort_suspend_source_add(ws->name);
> +#endif

Especially for stuff like this, if you write your .h files properly, no
#ifdef are needed.



> 		pm_system_wakeup();
> +	}
>  }
> 
>  /**
> @@ -893,12 +956,47 @@ bool pm_wakeup_pending(void)
> 		pm_print_active_wakeup_sources();
> 	}
> 
> +#ifdef CONFIG_PM_DEBUG
> +	if (atomic_read(&pm_abort_suspend) > 0) {
> +		struct pm_abort_suspend_source *info;
> +
> +		raw_spin_lock_irqsave(&pm_abort_suspend_list_lock, flags);
> +		list_for_each_entry(info, &pm_abort_suspend_list, list) {
> +			pm_pr_dbg("wakeup source or subsystem %s aborted suspend\n",
> +					info->source_triggering_abort_suspend);
> +		}
> +		raw_spin_unlock_irqrestore(&pm_abort_suspend_list_lock, flags);
> +		pm_abort_suspend_list_clear();
> +	}
> +#endif
> +
> 	return ret || atomic_read(&pm_abort_suspend) > 0;
>  }
>  EXPORT_SYMBOL_GPL(pm_wakeup_pending);
> 
>  void pm_system_wakeup(void)
>  {
> +
> +#ifdef CONFIG_PM_DEBUG
> +#ifdef CONFIG_DEBUG_INFO
> +	if (pm_suspend_target_state != PM_SUSPEND_ON) {
> +		char *source_name = kasprintf(GFP_ATOMIC,
> +					"%ps",
> +					__builtin_return_address(0));
> +		if (!source_name)
> +			goto exit;
> +
> +		if (strcmp(source_name, "pm_wakeup_ws_event"))
> +			pm_abort_suspend_source_add(source_name);
> +
> +		kfree(source_name);
> +	}
> +exit:
> +#else
> +	if (pm_suspend_target_state != PM_SUSPEND_ON)
> +		pm_pr_dbg("Some wakeup source or subsystem aborted suspend\n");
> +#endif
> +#endif

Would you want to maintain this #ifdef nesting mess for the next 20
years?  Please do not do this.

thanks,

greg k-h
Greg Kroah-Hartman Feb. 7, 2024, 10:25 a.m. UTC | #2
On Wed, Feb 07, 2024 at 09:24:57AM +0530, Vimal Kumar wrote:
> On Mon, Feb 05, 2024 at 07:33:17PM +0000, Greg Kroah-Hartman wrote:
> > On Mon, Feb 05, 2024 at 10:37:45PM +0530, Vimal Kumar wrote:
> > > Sometimes kernel suspend transitions can be aborted unconditionally by
> > > manipulating pm_abort_suspend value using "hard" wakeup triggers or
> > > through "pm_system_wakeup()".
> > > 
> > > There is no way to trace the source path of module or subsystem which
> > > aborted the suspend transitions. This change will create a list of
> > > wakeup sources aborting suspend in progress through "hard" events as
> > > well as subsytems aborting suspend using "pm_system_wakeup()".
> > > 
> > > Example: Existing suspend failure logs:
> > > [  349.708359] PM: Some devices failed to suspend, or early wake event detected
> > > [  350.327842] PM: suspend exit
> > > 
> > > Suspend failure logs with this change:
> > > [  518.761835] PM: Some devices failed to suspend, or early wake event detected
> > > [  519.486939] PM: wakeup source or subsystem uart_suspend_port aborted suspend
> > > [  519.500594] PM: suspend exit
> > > 
> > > Here we can clearly identify the module triggerring abort suspend.
> > > 
> > > Co-developed-by: Chinmoy Ghosh <chinmoyghosh2001@gmail.com>
> > > Signed-off-by: Chinmoy Ghosh <chinmoyghosh2001@gmail.com>
> > > Co-developed-by: Mintu Patel <mintupatel89@gmail.com>
> > > Signed-off-by: Mintu Patel <mintupatel89@gmail.com>
> > > Co-developed-by: Vishal Badole <badolevishal1116@gmail.com>
> > > Signed-off-by: Vishal Badole <badolevishal1116@gmail.com>
> > > Signed-off-by: Vimal Kumar <vimal.kumar32@gmail.com>
> > > ---
> > > Changes in v4:
> > > - Changed GFP_KERNEL flag to GFP_ATOMIC
> > > - Changed mutex_lock to raw_spin_lock
> > 
> > why raw?
> >
>  As mutex_lock might sleep, we need to use lock that is suitable for usages in atomic context. raw_spin_lock is already being used for other list in
> this driver, so I used the same. If suggested we can switch to spin_lock_irqsave as well.

You need a really good reason, and a documented one, as to why to use a
raw spinlock.  If not, please just use a normal one (or irqsave if it
can be grabbed in irq context.)

> > > +exit:
> > > +#else
> > > +	if (pm_suspend_target_state != PM_SUSPEND_ON)
> > > +		pm_pr_dbg("Some wakeup source or subsystem aborted suspend\n");
> > > +#endif
> > > +#endif
> > 
> > Would you want to maintain this #ifdef nesting mess for the next 20
> > years?  Please do not do this.
> > 
>  I was hoping if we can remove the "CONFIG_PM_DEBUG" as this functionality can exist by default as well.

Then submit changes for that if that is what you want :)

thanks,

greg k-h
diff mbox series

Patch

diff --git a/drivers/base/power/wakeup.c b/drivers/base/power/wakeup.c
index a917219feea6..b04794557eef 100644
--- a/drivers/base/power/wakeup.c
+++ b/drivers/base/power/wakeup.c
@@ -73,6 +73,16 @@  static struct wakeup_source deleted_ws = {

 static DEFINE_IDA(wakeup_ida);

+#ifdef CONFIG_PM_DEBUG
+static DEFINE_RAW_SPINLOCK(pm_abort_suspend_list_lock);
+
+struct pm_abort_suspend_source {
+	struct list_head list;
+	char *source_triggering_abort_suspend;
+};
+static LIST_HEAD(pm_abort_suspend_list);
+#endif
+
 /**
  * wakeup_source_create - Create a struct wakeup_source object.
  * @name: Name of the new wakeup source.
@@ -575,6 +585,54 @@  static void wakeup_source_activate(struct wakeup_source *ws)
	trace_wakeup_source_activate(ws->name, cec);
 }

+#ifdef CONFIG_PM_DEBUG
+/**
+ * pm_abort_suspend_list_clear - Clear pm_abort_suspend_list.
+ *
+ * The pm_abort_suspend_list will be cleared when system PM exits.
+ */
+static void pm_abort_suspend_list_clear(void)
+{
+	unsigned long flags;
+	struct pm_abort_suspend_source *info, *tmp;
+
+	raw_spin_lock_irqsave(&pm_abort_suspend_list_lock, flags);
+	list_for_each_entry_safe(info, tmp, &pm_abort_suspend_list, list) {
+		list_del(&info->list);
+		kfree(info);
+	}
+	raw_spin_unlock_irqrestore(&pm_abort_suspend_list_lock, flags);
+}
+
+/**
+ * pm_abort_suspend_source_add - Update pm_abort_suspend_list
+ * @source_name: Wakeup_source or function aborting suspend transitions.
+ *
+ * Add the source name responsible for updating the abort_suspend flag in the
+ * pm_abort_suspend_list.
+ */
+static void pm_abort_suspend_source_add(const char *source_name)
+{
+	unsigned long flags;
+	struct pm_abort_suspend_source *info;
+
+	info = kmalloc(sizeof(*info), GFP_ATOMIC);
+	if (!info)
+		return;
+
+	INIT_LIST_HEAD(&info->list);
+	info->source_triggering_abort_suspend = kstrdup(source_name, GFP_ATOMIC);
+	if (!info->source_triggering_abort_suspend) {
+		kfree(info);
+		return;
+	}
+
+	raw_spin_lock_irqsave(&pm_abort_suspend_list_lock, flags);
+	list_add_tail(&info->list, &pm_abort_suspend_list);
+	raw_spin_unlock_irqrestore(&pm_abort_suspend_list_lock, flags);
+}
+#endif
+
 /**
  * wakeup_source_report_event - Report wakeup event using the given source.
  * @ws: Wakeup source to report the event for.
@@ -590,8 +648,13 @@  static void wakeup_source_report_event(struct wakeup_source *ws, bool hard)
	if (!ws->active)
		wakeup_source_activate(ws);

-	if (hard)
+	if (hard) {
+#ifdef CONFIG_PM_DEBUG
+		if (pm_suspend_target_state != PM_SUSPEND_ON)
+			pm_abort_suspend_source_add(ws->name);
+#endif
		pm_system_wakeup();
+	}
 }

 /**
@@ -893,12 +956,47 @@  bool pm_wakeup_pending(void)
		pm_print_active_wakeup_sources();
	}

+#ifdef CONFIG_PM_DEBUG
+	if (atomic_read(&pm_abort_suspend) > 0) {
+		struct pm_abort_suspend_source *info;
+
+		raw_spin_lock_irqsave(&pm_abort_suspend_list_lock, flags);
+		list_for_each_entry(info, &pm_abort_suspend_list, list) {
+			pm_pr_dbg("wakeup source or subsystem %s aborted suspend\n",
+					info->source_triggering_abort_suspend);
+		}
+		raw_spin_unlock_irqrestore(&pm_abort_suspend_list_lock, flags);
+		pm_abort_suspend_list_clear();
+	}
+#endif
+
	return ret || atomic_read(&pm_abort_suspend) > 0;
 }
 EXPORT_SYMBOL_GPL(pm_wakeup_pending);

 void pm_system_wakeup(void)
 {
+
+#ifdef CONFIG_PM_DEBUG
+#ifdef CONFIG_DEBUG_INFO
+	if (pm_suspend_target_state != PM_SUSPEND_ON) {
+		char *source_name = kasprintf(GFP_ATOMIC,
+					"%ps",
+					__builtin_return_address(0));
+		if (!source_name)
+			goto exit;
+
+		if (strcmp(source_name, "pm_wakeup_ws_event"))
+			pm_abort_suspend_source_add(source_name);
+
+		kfree(source_name);
+	}
+exit:
+#else
+	if (pm_suspend_target_state != PM_SUSPEND_ON)
+		pm_pr_dbg("Some wakeup source or subsystem aborted suspend\n");
+#endif
+#endif
	atomic_inc(&pm_abort_suspend);
	s2idle_wake();
 }