[PATCH v2] iio: buffer: hw-consumer: fix use-after-free in error path

Felix Gu
2026-04-30T13:29:15Z

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().

Fixes: 48b66f8f936f ("iio: Add hardware consumer buffer support")
Reported-by: sashiko <sashiko-bot@kernel.org>
Closes: https://sashiko.dev/#/patchset/20260427-iio_buf-v1-1-2bbdac844647%40gmail.com
Signed-off-by: Felix Gu <ustc.gu@gmail.com>
---
Changes in v2:
- Fix Andy's comment.
- Add Reported-by tag.
- Link to v1: https://lore.kernel.org/r/20260428-iio-buf-v1-1-dcc63ff7b800@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..700528c9a0a4 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, *tmp;
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, tmp, &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>