* [PATCH] PM / s2idle: Clear the events_check_enabled flag
@ 2017-10-31 21:44 Rajat Jain
2017-11-06 11:13 ` Pavel Machek
0 siblings, 1 reply; 4+ messages in thread
From: Rajat Jain @ 2017-10-31 21:44 UTC (permalink / raw)
To: Rafael J. Wysocki, Pavel Machek, Len Brown, linux-pm,
linux-kernel, dtor, rajatxjain
Cc: Rajat Jain
Problem: This flag does not get cleared currently in the suspend or
resume path in the following cases:
* In case some driver's suspend routine returns an error.
* Successful s2idle case
* etc?
Why is this a problem: What happens is that the next suspend attempt
could fail even though the user did not enable the flag by writing to
/sys/power/wakeup_count. This is 1 use case how the issue can be seen
(but similar use case with driver suspend failure can be thought of):
1. Read /sys/power/wakeup_count
2. echo count > /sys/power/wakeup_count
3. echo freeze > /sys/power/wakeup_count
4. Let the system suspend, and wakeup the system using some wake source
that calls pm_wakeup_event() e.g. power button or something.
5. Note that the combined wakeup count would be incremented due
to the pm_wakeup_event() in the resume path.
6. After resuming the events_check_enabled flag is still set.
At this point if the user attempts to freeze again (without writing to
/sys/power/wakeup_count), the suspend would fail even though there has
been no wake event since the past resume.
What this patch does:
It moves the clearing of the flag to just before a resume is completed,
so that it is always cleared for the corner cases mentioned above.
Signed-off-by: Rajat Jain <rajatja@google.com>
---
kernel/power/suspend.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c
index ccd2d20e6b06..0685c4499431 100644
--- a/kernel/power/suspend.c
+++ b/kernel/power/suspend.c
@@ -437,7 +437,6 @@ static int suspend_enter(suspend_state_t state, bool *wakeup)
error = suspend_ops->enter(state);
trace_suspend_resume(TPS("machine_suspend"),
state, false);
- events_check_enabled = false;
} else if (*wakeup) {
error = -EBUSY;
}
@@ -582,6 +581,7 @@ static int enter_state(suspend_state_t state)
pm_restore_gfp_mask();
Finish:
+ events_check_enabled = false;
pm_pr_dbg("Finishing wakeup.\n");
suspend_finish();
Unlock:
--
2.15.0.403.gc27cc4dac6-goog
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] PM / s2idle: Clear the events_check_enabled flag
2017-10-31 21:44 [PATCH] PM / s2idle: Clear the events_check_enabled flag Rajat Jain
@ 2017-11-06 11:13 ` Pavel Machek
0 siblings, 0 replies; 4+ messages in thread
From: Pavel Machek @ 2017-11-06 11:13 UTC (permalink / raw)
To: Rajat Jain
Cc: Rafael J. Wysocki, Len Brown, linux-pm, linux-kernel, dtor, rajatxjain
[-- Attachment #1: Type: text/plain, Size: 1615 bytes --]
On Tue 2017-10-31 14:44:24, Rajat Jain wrote:
> Problem: This flag does not get cleared currently in the suspend or
> resume path in the following cases:
>
> * In case some driver's suspend routine returns an error.
> * Successful s2idle case
> * etc?
>
> Why is this a problem: What happens is that the next suspend attempt
> could fail even though the user did not enable the flag by writing to
> /sys/power/wakeup_count. This is 1 use case how the issue can be seen
> (but similar use case with driver suspend failure can be thought of):
>
> 1. Read /sys/power/wakeup_count
> 2. echo count > /sys/power/wakeup_count
> 3. echo freeze > /sys/power/wakeup_count
> 4. Let the system suspend, and wakeup the system using some wake source
> that calls pm_wakeup_event() e.g. power button or something.
> 5. Note that the combined wakeup count would be incremented due
> to the pm_wakeup_event() in the resume path.
> 6. After resuming the events_check_enabled flag is still set.
>
> At this point if the user attempts to freeze again (without writing to
> /sys/power/wakeup_count), the suspend would fail even though there has
> been no wake event since the past resume.
>
> What this patch does:
>
> It moves the clearing of the flag to just before a resume is completed,
> so that it is always cleared for the corner cases mentioned above.
>
> Signed-off-by: Rajat Jain <rajatja@google.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
[-- Attachment #2: Digital signature --]
[-- Type: application/pgp-signature, Size: 181 bytes --]
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] PM / s2idle: Clear the events_check_enabled flag
2018-05-10 23:34 ` [PATCH] PM / s2idle: Clear the events_check_enabled flag Rajat Jain
@ 2018-05-10 23:36 ` Rajat Jain
0 siblings, 0 replies; 4+ messages in thread
From: Rajat Jain @ 2018-05-10 23:36 UTC (permalink / raw)
To: Rafael J. Wysocki, Pavel Machek, Len Brown, Linux PM,
Linux Kernel Mailing List, Dmitry Torokhov, Rajat Jain
Cc: Rajat Jain
Sorry, please ignore, sent by mistake.
On Thu, May 10, 2018 at 4:34 PM, Rajat Jain <rajatja@google.com> wrote:
> Problem: This flag does not get cleared currently in the suspend or
> resume path in the following cases:
>
> * In case some driver's suspend routine returns an error.
> * Successful s2idle case
> * etc?
>
> Why is this a problem: What happens is that the next suspend attempt
> could fail even though the user did not enable the flag by writing to
> /sys/power/wakeup_count. This is 1 use case how the issue can be seen
> (but similar use case with driver suspend failure can be thought of):
>
> 1. Read /sys/power/wakeup_count
> 2. echo count > /sys/power/wakeup_count
> 3. echo freeze > /sys/power/wakeup_count
> 4. Let the system suspend, and wakeup the system using some wake source
> that calls pm_wakeup_event() e.g. power button or something.
> 5. Note that the combined wakeup count would be incremented due
> to the pm_wakeup_event() in the resume path.
> 6. After resuming the events_check_enabled flag is still set.
>
> At this point if the user attempts to freeze again (without writing to
> /sys/power/wakeup_count), the suspend would fail even though there has
> been no wake event since the past resume.
>
> What this patch does:
>
> It moves the clearing of the flag to just before a resume is completed,
> so that it is always cleared for the corner cases mentioned above.
>
> Signed-off-by: Rajat Jain <rajatja@google.com>
> ---
> kernel/power/suspend.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c
> index ccd2d20e6b06..0685c4499431 100644
> --- a/kernel/power/suspend.c
> +++ b/kernel/power/suspend.c
> @@ -437,7 +437,6 @@ static int suspend_enter(suspend_state_t state, bool *wakeup)
> error = suspend_ops->enter(state);
> trace_suspend_resume(TPS("machine_suspend"),
> state, false);
> - events_check_enabled = false;
> } else if (*wakeup) {
> error = -EBUSY;
> }
> @@ -582,6 +581,7 @@ static int enter_state(suspend_state_t state)
> pm_restore_gfp_mask();
>
> Finish:
> + events_check_enabled = false;
> pm_pr_dbg("Finishing wakeup.\n");
> suspend_finish();
> Unlock:
> --
> 2.15.0.403.gc27cc4dac6-goog
>
^ permalink raw reply [flat|nested] 4+ messages in thread
* [PATCH] PM / s2idle: Clear the events_check_enabled flag
2018-05-08 23:01 [PATCH] pci/aspm: Remove CONFIG_PCIEASPM_DEBUG Rajat Jain
@ 2018-05-10 23:34 ` Rajat Jain
2018-05-10 23:36 ` Rajat Jain
0 siblings, 1 reply; 4+ messages in thread
From: Rajat Jain @ 2018-05-10 23:34 UTC (permalink / raw)
To: Rafael J. Wysocki, Pavel Machek, Len Brown, linux-pm,
linux-kernel, dtor, rajatxjain
Cc: Rajat Jain
Problem: This flag does not get cleared currently in the suspend or
resume path in the following cases:
* In case some driver's suspend routine returns an error.
* Successful s2idle case
* etc?
Why is this a problem: What happens is that the next suspend attempt
could fail even though the user did not enable the flag by writing to
/sys/power/wakeup_count. This is 1 use case how the issue can be seen
(but similar use case with driver suspend failure can be thought of):
1. Read /sys/power/wakeup_count
2. echo count > /sys/power/wakeup_count
3. echo freeze > /sys/power/wakeup_count
4. Let the system suspend, and wakeup the system using some wake source
that calls pm_wakeup_event() e.g. power button or something.
5. Note that the combined wakeup count would be incremented due
to the pm_wakeup_event() in the resume path.
6. After resuming the events_check_enabled flag is still set.
At this point if the user attempts to freeze again (without writing to
/sys/power/wakeup_count), the suspend would fail even though there has
been no wake event since the past resume.
What this patch does:
It moves the clearing of the flag to just before a resume is completed,
so that it is always cleared for the corner cases mentioned above.
Signed-off-by: Rajat Jain <rajatja@google.com>
---
kernel/power/suspend.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c
index ccd2d20e6b06..0685c4499431 100644
--- a/kernel/power/suspend.c
+++ b/kernel/power/suspend.c
@@ -437,7 +437,6 @@ static int suspend_enter(suspend_state_t state, bool *wakeup)
error = suspend_ops->enter(state);
trace_suspend_resume(TPS("machine_suspend"),
state, false);
- events_check_enabled = false;
} else if (*wakeup) {
error = -EBUSY;
}
@@ -582,6 +581,7 @@ static int enter_state(suspend_state_t state)
pm_restore_gfp_mask();
Finish:
+ events_check_enabled = false;
pm_pr_dbg("Finishing wakeup.\n");
suspend_finish();
Unlock:
--
2.15.0.403.gc27cc4dac6-goog
^ permalink raw reply related [flat|nested] 4+ messages in thread
end of thread, other threads:[~2018-05-10 23:37 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2017-10-31 21:44 [PATCH] PM / s2idle: Clear the events_check_enabled flag Rajat Jain
2017-11-06 11:13 ` Pavel Machek
2018-05-08 23:01 [PATCH] pci/aspm: Remove CONFIG_PCIEASPM_DEBUG Rajat Jain
2018-05-10 23:34 ` [PATCH] PM / s2idle: Clear the events_check_enabled flag Rajat Jain
2018-05-10 23:36 ` Rajat Jain
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