On Thursday 09 April 2015 02:28:41 Rafael J. Wysocki wrote:

On Sunday, April 05, 2015 07:20:17 PM Pali Rohár wrote:

quoted

To prevent race conditions on userspace processes with I/O
some taks must be called after processes are freezed. This
patch adds new events which are delivered by
pm_notifier_call_chain() after freezing processes when
doing suspend or hibernate action.

Signed-off-by: Pali Rohár <redacted>

Please don't add more notifiers.  Just call whatever you need
directly from where you need to call that.

If that is device-related, try to use device PM
suspend/hibernate callbacks instead.

Hi! It is not possible to use any exiting pm notifiers! This is 
reason why I added new ones. As I wrote wiping dm crypt keys must 
be done *after* userspace processes are freezed to prevent race 
conditions...

quoted

---

 include/linux/suspend.h  |    2 ++
 kernel/power/hibernate.c |    2 ++
 kernel/power/suspend.c   |    4 +++-
 3 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/include/linux/suspend.h

b/include/linux/suspend.h index 5efe743..bc743c8 100644

--- a/include/linux/suspend.h
+++ b/include/linux/suspend.h

@@ -368,6 +368,8 @@ static inline bool

hibernation_available(void) { return false; }

 #define PM_POST_SUSPEND		0x0004 /* Suspend finished */
 #define PM_RESTORE_PREPARE	0x0005 /* Going to restore a
 saved image */ #define PM_POST_RESTORE		0x0006 /*
 Restore
 failed */

+#define PM_HIBERNATION_AFTER_FREEZE	0x0007 /* After
hibernation freeze */ +#define
PM_SUSPEND_AFTER_FREEZE		0x0008 /* After suspend freeze */

 extern struct mutex pm_mutex;

diff --git a/kernel/power/hibernate.c

b/kernel/power/hibernate.c index 2329daa..184f7ee 100644

--- a/kernel/power/hibernate.c
+++ b/kernel/power/hibernate.c

@@ -671,6 +671,8 @@ int hibernate(void)

 	if (error)
 	
 		goto Exit;

+	pm_notifier_call_chain(PM_HIBERNATION_AFTER_FREEZE);
+

 	lock_device_hotplug();
 	/* Allocate memory management structures */
 	error = create_basic_memory_bitmaps();

diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c
index b7d6b3a..1776938 100644
--- a/kernel/power/suspend.c
+++ b/kernel/power/suspend.c

@@ -268,8 +268,10 @@ static int

suspend_prepare(suspend_state_t state)

 	trace_suspend_resume(TPS("freeze_processes"), 0, true);
 	error = suspend_freeze_processes();
 	trace_suspend_resume(TPS("freeze_processes"), 0, false);

-	if (!error)
+	if (!error) {
+		pm_notifier_call_chain(PM_SUSPEND_AFTER_FREEZE);

 		return 0;

+	}

 	suspend_stats.failed_freeze++;
 	dpm_save_failed_step(SUSPEND_FREEZE);

-- 
Pali Rohár
pali.rohar@gmail.com