Hi,
On 09/12/2024 11:09, Sakari Ailus wrote:
> Huomenta,
>
> On Wed, Dec 04, 2024 at 01:05:15PM +0200, Tomi Valkeinen wrote:
>> The ub913 and ub953 drivers call fwnode_handle_put(priv->sd.fwnode) as
>> part of their remove process, and if the driver is removed multiple
>> times, eventually leads to put "overflow", possibly causing memory
>
> This is, in fact, an extra put. It'll lead to underflow, not overflow.
Well, there are too many puts, so "put overflow" =). I don't think
underflow is the right word here either, but it's probably better than
overflow. Maybe I'll reword it so that it doesn't have a flow at all.
> I'd expect removing it once would be already too much.
True, but there's something keeping some refs to the fwnode even without
these drivers (otherwise they'd be freed when these drivers are not
around), so the issue shows only when those refs are taken out by the
puts in these drivers.
Tomi
>
>> corruption or crash.
>>
>> The fwnode_handle_put() is a leftover from commit 905f88ccebb1 ("media:
>> i2c: ds90ub9x3: Fix sub-device matching"), which changed the code
>> related to the sd.fwnode, but missed removing these fwnode_handle_put()
>> calls.
>>
>> Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
>> Cc: stable@vger.kernel.org
>> Fixes: 905f88ccebb1 ("media: i2c: ds90ub9x3: Fix sub-device matching")
>> ---
>> drivers/media/i2c/ds90ub913.c | 1 -
>> drivers/media/i2c/ds90ub953.c | 1 -
>> 2 files changed, 2 deletions(-)
>>
>> diff --git a/drivers/media/i2c/ds90ub913.c b/drivers/media/i2c/ds90ub913.c
>> index 8eed4a200fd8..b5375d736629 100644
>> --- a/drivers/media/i2c/ds90ub913.c
>> +++ b/drivers/media/i2c/ds90ub913.c
>> @@ -793,7 +793,6 @@ static void ub913_subdev_uninit(struct ub913_data *priv)
>> v4l2_async_unregister_subdev(&priv->sd);
>> ub913_v4l2_nf_unregister(priv);
>> v4l2_subdev_cleanup(&priv->sd);
>> - fwnode_handle_put(priv->sd.fwnode);
>> media_entity_cleanup(&priv->sd.entity);
>> }
>>
>> diff --git a/drivers/media/i2c/ds90ub953.c b/drivers/media/i2c/ds90ub953.c
>> index 16f88db14981..10daecf6f457 100644
>> --- a/drivers/media/i2c/ds90ub953.c
>> +++ b/drivers/media/i2c/ds90ub953.c
>> @@ -1291,7 +1291,6 @@ static void ub953_subdev_uninit(struct ub953_data *priv)
>> v4l2_async_unregister_subdev(&priv->sd);
>> ub953_v4l2_notifier_unregister(priv);
>> v4l2_subdev_cleanup(&priv->sd);
>> - fwnode_handle_put(priv->sd.fwnode);
>> media_entity_cleanup(&priv->sd.entity);
>> }
>>
>>
>