releases/4.19.31/pm-wakeup-rework-wakeup-source-timer-cancellation.patch

   1 From 1fad17fb1bbcd73159c2b992668a6957ecc5af8a Mon Sep 17 00:00:00 2001
   2 From: Viresh Kumar <viresh.kumar@linaro.org>
   3 Date: Fri, 8 Mar 2019 15:23:11 +0530
   4 Subject: PM / wakeup: Rework wakeup source timer cancellation
   5
   6 From: Viresh Kumar <viresh.kumar@linaro.org>
   7
   8 commit 1fad17fb1bbcd73159c2b992668a6957ecc5af8a upstream.
   9
  10 If wakeup_source_add() is called right after wakeup_source_remove()
  11 for the same wakeup source, timer_setup() may be called for a
  12 potentially scheduled timer which is incorrect.
  13
  14 To avoid that, move the wakeup source timer cancellation from
  15 wakeup_source_drop() to wakeup_source_remove().
  16
  17 Moreover, make wakeup_source_remove() clear the timer function after
  18 canceling the timer to let wakeup_source_not_registered() treat
  19 unregistered wakeup sources in the same way as the ones that have
  20 never been registered.
  21
  22 Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
  23 Cc: 4.4+ <stable@vger.kernel.org> # 4.4+
  24 [ rjw: Subject, changelog, merged two patches together ]
  25 Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
  26 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  27
  28 ---
  29  drivers/base/power/wakeup.c |    8 +++++++-
  30  1 file changed, 7 insertions(+), 1 deletion(-)
  31
  32 --- a/drivers/base/power/wakeup.c
  33 +++ b/drivers/base/power/wakeup.c
  34 @@ -118,7 +118,6 @@ void wakeup_source_drop(struct wakeup_so
  35         if (!ws)
  36                 return;
  37
  38 -       del_timer_sync(&ws->timer);
  39         __pm_relax(ws);
  40  }
  41  EXPORT_SYMBOL_GPL(wakeup_source_drop);
  42 @@ -205,6 +204,13 @@ void wakeup_source_remove(struct wakeup_
  43         list_del_rcu(&ws->entry);
  44         raw_spin_unlock_irqrestore(&events_lock, flags);
  45         synchronize_srcu(&wakeup_srcu);
  46 +
  47 +       del_timer_sync(&ws->timer);
  48 +       /*
  49 +        * Clear timer.function to make wakeup_source_not_registered() treat
  50 +        * this wakeup source as not registered.
  51 +        */
  52 +       ws->timer.function = NULL;
  53  }
  54  EXPORT_SYMBOL_GPL(wakeup_source_remove);
  55