| Message ID | 20171031214424.84783-1-rajatja@google.com (mailing list archive) |
|---|---|
| State | Accepted, archived |
| Delegated to: | Rafael Wysocki |
| Headers | show |
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>
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:
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(-)