This is a note to let you know that I've just added the patch titled

iio: light: opt3001: fix mutex unlock race

to my staging git tree which can be found at git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging.git in the staging-linus branch.

The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.)

The patch will hopefully also be merged in Linus's tree for the next -rc kernel release.

If you have any questions about this process, please let me know.

From 82f3015635249a8c8c45bac303fd84905066f04f Mon Sep 17 00:00:00 2001

From: David Frey dpfrey@gmail.com Date: Thu, 19 Sep 2019 15:54:18 -0700 Subject: iio: light: opt3001: fix mutex unlock race

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 --- drivers/iio/light/opt3001.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/iio/light/opt3001.c b/drivers/iio/light/opt3001.c index e666879007d2..92004a2563ea 100644 --- a/drivers/iio/light/opt3001.c +++ b/drivers/iio/light/opt3001.c @@ -686,6 +686,7 @@ static irqreturn_t opt3001_irq(int irq, void *_iio) 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); @@ -720,13 +721,16 @@ static irqreturn_t opt3001_irq(int irq, void *_iio) } 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; }