From: David Frey dpfrey@gmail.com
commit 82f3015635249a8c8c45bac303fd84905066f04f upstream.
When an end-of-conversion interrupt is received after performing a single-shot reading of the light sensor, the driver was waking up the result ready queue before checking opt->ok_to_ignore_lock to determine if it should unlock the mutex. The problem occurred in the case where the other thread woke up and changed the value of opt->ok_to_ignore_lock to false prior to the interrupt thread performing its read of the variable. In this case, the mutex would be unlocked twice.
Signed-off-by: David Frey dpfrey@gmail.com Reviewed-by: Andreas Dannenberg dannenberg@ti.com Fixes: 94a9b7b1809f ("iio: light: add support for TI's opt3001 light sensor") Cc: Stable@vger.kernel.org Signed-off-by: Jonathan Cameron Jonathan.Cameron@huawei.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/iio/light/opt3001.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)
--- a/drivers/iio/light/opt3001.c +++ b/drivers/iio/light/opt3001.c @@ -646,6 +646,7 @@ static irqreturn_t opt3001_irq(int irq, struct iio_dev *iio = _iio; struct opt3001 *opt = iio_priv(iio); int ret; + bool wake_result_ready_queue = false;
if (!opt->ok_to_ignore_lock) mutex_lock(&opt->lock); @@ -680,13 +681,16 @@ static irqreturn_t opt3001_irq(int irq, } opt->result = ret; opt->result_ready = true; - wake_up(&opt->result_ready_queue); + wake_result_ready_queue = true; }
out: if (!opt->ok_to_ignore_lock) mutex_unlock(&opt->lock);
+ if (wake_result_ready_queue) + wake_up(&opt->result_ready_queue); + return IRQ_HANDLED; }