On Tue, Jan 31, 2023 at 03:01:09PM +0100, Mårten Lindahl wrote:
> There are different init functions for the sensors in this driver in
> which only one initializes the generic vcnl4000_lock. With commit
> e21b5b1f2669 ("iio: light: vcnl4000: Preserve conf bits when toggle power")
> the vcnl4040 sensor started to depend on the lock, but it was missed to
> initialize it in vcnl4040's init function. This has not been visible
> until we run lockdep on it:
>
> DEBUG_LOCKS_WARN_ON(lock->magic != lock)
> at kernel/locking/mutex.c:575 __mutex_lock+0x4f8/0x890
> Call trace:
> __mutex_lock
> mutex_lock_nested
> vcnl4200_set_power_state
> vcnl4200_init
> vcnl4000_probe
>
> Fix this by initializing the lock in the probe function instead of doing
> it in the chip specific init functions.
Fine now, thanks!
Reviewed-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
> Fixes: e21b5b1f2669 ("iio: light: vcnl4000: Preserve conf bits when toggle power")
> Signed-off-by: Mårten Lindahl <marten.lindahl@xxxxxxxx>
> ---
>
> v3:
> - Trimmed backtrace in commit message even more
> - New line before mutex_init
>
> v2:
> - Trimmed backtrace in commit message
> - Have 12 digit sha-1 id in Fixes tag
> - Make the lock initialization in probe instead of in _init function
>
> drivers/iio/light/vcnl4000.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/iio/light/vcnl4000.c b/drivers/iio/light/vcnl4000.c
> index cc1a2062e76d..69c5bc987e26 100644
> --- a/drivers/iio/light/vcnl4000.c
> +++ b/drivers/iio/light/vcnl4000.c
> @@ -199,7 +199,6 @@ static int vcnl4000_init(struct vcnl4000_data *data)
>
> data->rev = ret & 0xf;
> data->al_scale = 250000;
> - mutex_init(&data->vcnl4000_lock);
>
> return data->chip_spec->set_power_state(data, true);
> };
> @@ -1197,6 +1196,8 @@ static int vcnl4000_probe(struct i2c_client *client)
> data->id = id->driver_data;
> data->chip_spec = &vcnl4000_chip_spec_cfg[data->id];
>
> + mutex_init(&data->vcnl4000_lock);
> +
> ret = data->chip_spec->init(data);
> if (ret < 0)
> return ret;
> --
> 2.30.2
>
--
With Best Regards,
Andy Shevchenko
