[PATCH] iio: trigger: Fix error handling in viio_trigger_alloc

[PATCH] iio: trigger: Fix error handling in viio_trigger_alloc

[Ma Ke]

viio_trigger_alloc() initializes the device with device_initialize()
but uses kfree() directly in error paths, which bypasses the device's
release callback iio_trig_release(). This could lead to memory leaks
and inconsistent device state.

Replace kfree(trig) with put_device(&trig->dev) in error paths to
ensure proper cleanup through the device's release callback.

Found by code review.

Cc: stable@vger.kernel.org
Fixes: 2c99f1a09da3 ("iio: trigger: clean up viio_trigger_alloc()")
Signed-off-by: Ma Ke <make24@iscas.ac.cn>
---
 drivers/iio/industrialio-trigger.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/iio/industrialio-trigger.c b/drivers/iio/industrialio-trigger.c
index 54416a384232..981e19757870 100644
--- a/drivers/iio/industrialio-trigger.c
+++ b/drivers/iio/industrialio-trigger.c
@@ -597,7 +597,7 @@ struct iio_trigger *viio_trigger_alloc(struct device *parent,
 free_descs:
 	irq_free_descs(trig->subirq_base, CONFIG_IIO_CONSUMERS_PER_TRIGGER);
 free_trig:
-	kfree(trig);
+	put_device(&trig->dev);
 	return NULL;
 }
 
-- 
2.17.1

Re: [PATCH] iio: trigger: Fix error handling in viio_trigger_alloc

[Andy Shevchenko]

On Wed, Nov 05, 2025 at 05:47:14PM +0800, Ma Ke wrote:
> viio_trigger_alloc() initializes the device with device_initialize()
> but uses kfree() directly in error paths, which bypasses the device's
> release callback iio_trig_release(). This could lead to memory leaks
> and inconsistent device state.
> 
> Replace kfree(trig) with put_device(&trig->dev) in error paths to
> ensure proper cleanup through the device's release callback.

Now when irq_alloc_descs() fails, trig->subirq_base becomes negative and
in the release callback it will pass the

        if (trig->subirq_base) {

Is it a problem?

The release function also misses mutex_destroy().

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH] iio: trigger: Fix error handling in viio_trigger_alloc

[Andy Shevchenko]

On Wed, Nov 05, 2025 at 05:04:32PM +0200, Andy Shevchenko wrote:
> On Wed, Nov 05, 2025 at 05:47:14PM +0800, Ma Ke wrote:
> > viio_trigger_alloc() initializes the device with device_initialize()
> > but uses kfree() directly in error paths, which bypasses the device's
> > release callback iio_trig_release(). This could lead to memory leaks
> > and inconsistent device state.
> > 
> > Replace kfree(trig) with put_device(&trig->dev) in error paths to
> > ensure proper cleanup through the device's release callback.
> 
> Now when irq_alloc_descs() fails, trig->subirq_base becomes negative and
> in the release callback it will pass the
> 
>         if (trig->subirq_base) {
> 
> Is it a problem?
> 
> The release function also misses mutex_destroy().

Ah, and if kvasprintf() fails, the error path will call irq_free_descs() and
then one more time in the release callback.

You finding is good, but the fix needs to be crafted thoughtfully.

-- 
With Best Regards,
Andy Shevchenko