diff mbox series

[v3] iio: light: vcnl4000: Fix WARN_ON on uninitialized lock

Message ID 20230131140109.2067577-1-marten.lindahl@axis.com (mailing list archive)
State Accepted
Headers show
Series [v3] iio: light: vcnl4000: Fix WARN_ON on uninitialized lock | expand

Commit Message

Mårten Lindahl Jan. 31, 2023, 2:01 p.m. UTC
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.

Fixes: e21b5b1f2669 ("iio: light: vcnl4000: Preserve conf bits when toggle power")
Signed-off-by: Mårten Lindahl <marten.lindahl@axis.com>
---

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(-)

Comments

Andy Shevchenko Jan. 31, 2023, 2:14 p.m. UTC | #1
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@linux.intel.com>

> Fixes: e21b5b1f2669 ("iio: light: vcnl4000: Preserve conf bits when toggle power")
> Signed-off-by: Mårten Lindahl <marten.lindahl@axis.com>
> ---
> 
> 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
>
Jonathan Cameron Feb. 2, 2023, 5:12 p.m. UTC | #2
On Tue, 31 Jan 2023 16:14:11 +0200
Andy Shevchenko <andriy.shevchenko@linux.intel.com> wrote:

> 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@linux.intel.com>
> 
> > Fixes: e21b5b1f2669 ("iio: light: vcnl4000: Preserve conf bits when toggle power")
> > Signed-off-by: Mårten Lindahl <marten.lindahl@axis.com>
Applied to the fixes-togreg branch and marked for stable.

Thanks,

Jonathan

> > ---
> > 
> > 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
> >   
>
diff mbox series

Patch

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;