Commit e9728f0d authored by Dmitry Torokhov's avatar Dmitry Torokhov
Browse files

Input: pwm-beeper - fix race when suspending

Usually userspace sends SND_BELL and SND_TONE events, and by the time
pwm_beeper_suspend() runs userpsace is already frozen, but theoretically
in-kernel users may send these events too, and that may cause
pwm_beeper_event() scheduling another work after we canceled it.

Let's introduce a "suspended" flag and check it in pwm_beeper_event() to
avoid this race.
Reviewed-by: default avatarThierry Reding <>
Tested-by: default avatarDavid Lechner <>
Signed-off-by: default avatarDmitry Torokhov <>
parent 48a55d7d
......@@ -27,6 +27,7 @@ struct pwm_beeper {
struct pwm_device *pwm;
struct work_struct work;
unsigned long period;
bool suspended;
#define HZ_TO_NANOSECONDS(x) (1000000000UL/(x))
......@@ -73,7 +74,8 @@ static int pwm_beeper_event(struct input_dev *input,
beeper->period = HZ_TO_NANOSECONDS(value);
if (!beeper->suspended)
return 0;
......@@ -154,6 +156,15 @@ static int __maybe_unused pwm_beeper_suspend(struct device *dev)
struct pwm_beeper *beeper = dev_get_drvdata(dev);
* Spinlock is taken here is not to protect write to
* beeper->suspended, but to ensure that pwm_beeper_event
* does not re-submit work once flag is set.
beeper->suspended = true;
return 0;
......@@ -163,8 +174,12 @@ static int __maybe_unused pwm_beeper_resume(struct device *dev)
struct pwm_beeper *beeper = dev_get_drvdata(dev);
if (beeper->period)
beeper->suspended = false;
/* Let worker figure out if we should resume beeping */
return 0;
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