linux-kernel - [PATCH v3] iio: trigger: Fix error handling in viio_trigger

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Message-Id: <20251107020200.6285-1-make24@iscas.ac.cn>
Date: Fri,  7 Nov 2025 10:02:00 +0800
From: Ma Ke <make24@...as.ac.cn>
To: jic23@...nel.org,
	dlechner@...libre.com,
	nuno.sa@...log.com,
	andy@...nel.org
Cc: linux-iio@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	akpm@...ux-foundation.org,
	Ma Ke <make24@...as.ac.cn>
Subject: [PATCH v3] iio: trigger: Fix error handling in viio_trigger_alloc

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.

Additionally, the current error handling has the following issues:
1. Potential double-free of IRQ descriptors when kvasprintf() fails.
2. The release function may attempt to free negative subirq_base.
3. Missing mutex_destroy() in release function.

Fix these issues by:
1. Replacing kfree(trig) with put_device(&trig->dev) in error paths.
2. Removing the free_descs label and handling IRQ descriptor freeing
   directly in the kvasprintf() error path.
3. Adding missing mutex_destroy().

Found by code review.

Signed-off-by: Ma Ke <make24@...as.ac.cn>
---
 drivers/iio/industrialio-trigger.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/drivers/iio/industrialio-trigger.c b/drivers/iio/industrialio-trigger.c
index 54416a384232..7576dedee68e 100644
--- a/drivers/iio/industrialio-trigger.c
+++ b/drivers/iio/industrialio-trigger.c
@@ -524,6 +524,7 @@ static void iio_trig_release(struct device *device)
 			       CONFIG_IIO_CONSUMERS_PER_TRIGGER);
 	}
 	kfree(trig->name);
+	mutex_destroy(&trig->pool_lock);
 	kfree(trig);
 }

@@ -575,8 +576,10 @@ struct iio_trigger *viio_trigger_alloc(struct device *parent,
 		goto free_trig;

 	trig->name = kvasprintf(GFP_KERNEL, fmt, vargs);
-	if (trig->name == NULL)
-		goto free_descs;
+	if (trig->name == NULL) {
+		irq_free_descs(trig->subirq_base, CONFIG_IIO_CONSUMERS_PER_TRIGGER);
+		goto free_trig;
+	}

 	INIT_LIST_HEAD(&trig->list);

@@ -594,10 +597,8 @@ struct iio_trigger *viio_trigger_alloc(struct device *parent,

 	return trig;

-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