Re: [PATCH] iio: buffer: hw-consumer: free scan_mask on buffer release

[Jonathan Cameron <jic23@kernel.org>]

On Mon, 27 Apr 2026 19:11:39 +0800
Felix Gu <ustc.gu@gmail.com> wrote:

> The scan_mask lifetime changed in commit 9a2e1233d38c ("iio: buffer:
> hw-consumer: remove redundant scan_mask flexible array").
> 
> Before that change, the scan mask storage was embedded in struct
> hw_consumer_buffer, so iio_hw_buf_release() could free the whole
> allocation with a single kfree(hw_buf).

> 
> That commit moved the scan mask to a separate bitmap_zalloc() allocation

> stored in buffer.scan_mask, but left iio_hw_buf_release() unchanged.

Hmm. This reuse of a pointer that is otherwise set via very different
paths sent me down a wild goose chase.

Patch seems fine, but I'd like Nuno to take a quick look before I pick it up.

Jonathan

> 
> Free the scan mask in iio_hw_buf_release() before freeing the buffer
> wrapper.
> 
> Fixes: 9a2e1233d38c ("iio: buffer: hw-consumer: remove redundant scan_mask flexible array")
> Signed-off-by: Felix Gu <ustc.gu@gmail.com>
> ---
>  drivers/iio/buffer/industrialio-hw-consumer.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/iio/buffer/industrialio-hw-consumer.c b/drivers/iio/buffer/industrialio-hw-consumer.c
> index 24d7df603760..d1ab2cbf8c88 100644
> --- a/drivers/iio/buffer/industrialio-hw-consumer.c
> +++ b/drivers/iio/buffer/industrialio-hw-consumer.c
> @@ -40,6 +40,8 @@ static void iio_hw_buf_release(struct iio_buffer *buffer)
>  {
>  	struct hw_consumer_buffer *hw_buf =
>  		iio_buffer_to_hw_consumer_buffer(buffer);
> +
> +	bitmap_free(buffer->scan_mask);
>  	kfree(hw_buf);
>  }
>  
> 
> ---
> base-commit: 7080e32d3f09d8688c4a87d81bdcc71f7f606b16
> change-id: 20260427-iio_buf-0459b3fa3de8
> 
> Best regards,