[PATCH] iio: buffer: hw-consumer: fix use-after-free in error path

[Felix Gu <ustc.gu@gmail.com>]

In the err_put_buffers cleanup path of iio_hw_consumer_alloc(), the code
was using list_for_each_entry() to iterate through buffers while calling
iio_buffer_put() which can free the current buffer if refcount drops to 0.
The list_for_each_entry() loop macro then evaluates buf->head.next to
continue iteration, accessing the freed buffer.

Fix this by using list_for_each_entry_safe().

Closes:https://sashiko.dev/#/patchset/20260427-iio_buf-v1-1-2bbdac844647%40gmail.com

Fixes: 48b66f8f936f ("iio: Add hardware consumer buffer support")
Signed-off-by: Felix Gu <ustc.gu@gmail.com>
---
 drivers/iio/buffer/industrialio-hw-consumer.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/iio/buffer/industrialio-hw-consumer.c b/drivers/iio/buffer/industrialio-hw-consumer.c
index 24d7df603760..7406efefc123 100644
--- a/drivers/iio/buffer/industrialio-hw-consumer.c
+++ b/drivers/iio/buffer/industrialio-hw-consumer.c
@@ -85,7 +85,7 @@ static struct hw_consumer_buffer *iio_hw_consumer_get_buffer(
  */
 struct iio_hw_consumer *iio_hw_consumer_alloc(struct device *dev)
 {
-	struct hw_consumer_buffer *buf;
+	struct hw_consumer_buffer *buf, *n;
 	struct iio_hw_consumer *hwc;
 	struct iio_channel *chan;
 	int ret;
@@ -116,7 +116,7 @@ struct iio_hw_consumer *iio_hw_consumer_alloc(struct device *dev)
 	return hwc;
 
 err_put_buffers:
-	list_for_each_entry(buf, &hwc->buffers, head)
+	list_for_each_entry_safe(buf, n, &hwc->buffers, head)
 		iio_buffer_put(&buf->buffer);
 	iio_channel_release_all(hwc->channels);
 err_free_hwc:

---
base-commit: 7080e32d3f09d8688c4a87d81bdcc71f7f606b16
change-id: 20260428-iio-buf-4c8559020a54

Best regards,
-- 
Felix Gu <ustc.gu@gmail.com>