Re: [PATCH] dmaengine: idxd: Fix saved engines array leak in config save

[Frank Li]

On Sun, Apr 19, 2026 at 10:08:39PM +0800, Guangshuo Li wrote:
> idxd_device_config_save() uses cleanup.h helpers for temporary
> allocations while saving device configuration. The saved_groups and
> saved_wqs pointer arrays are declared with __free(kfree), and ownership
> is transferred to idxd_saved with no_free_ptr() on the success path.
>
> The saved_engines pointer array follows the same ownership pattern on the
> success path, but it is not declared with __free(kfree). As a result, if
> an error happens after saved_engines is allocated, idxd_free_saved()
> frees the saved engine objects but not the saved_engines array itself.
>
> This leaks saved_engines on error paths such as:
>   - failure to allocate an individual saved engine
>   - failure to allocate saved_wq_enable_map
>   - failure to allocate saved_wqs
>   - failure to allocate an individual saved WQ
>
> Declare saved_engines with __free(kfree) so the array is released
> automatically on failure, matching saved_groups and saved_wqs. The success
> path is unchanged because ownership is already transferred with
> no_free_ptr().
>
> Fixes: 6078a315aec1 ("dmaengine: idxd: Add idxd_device_config_save() and idxd_device_config_restore() helpers")
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Guangshuo Li <lgs201920130244@xxxxxxxxx>
> ---
>  drivers/dma/idxd/init.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/dma/idxd/init.c b/drivers/dma/idxd/init.c
> index f1cfc7790d95..02210f16d391 100644
> --- a/drivers/dma/idxd/init.c
> +++ b/drivers/dma/idxd/init.c
> @@ -880,7 +880,7 @@ static int idxd_device_config_save(struct idxd_device *idxd,
>  		saved_groups[i] = no_free_ptr(saved_group);
>  	}
>
> -	struct idxd_engine **saved_engines =
> +	struct idxd_engine **saved_engines __free(kfree) =
>  			kcalloc_node(idxd->max_engines,
>  				     sizeof(struct idxd_engine *),
>  				     GFP_KERNEL, dev_to_node(dev));

The follow code have problem.

saved_engines[i] = no_free_ptr(saved_engine);

if (...)
        return -ENOMEM;

there should not have an error branch after no_free_ptr(), you mix to use
manual and auto alloc()/free(), which may cause hidden problem.

Frank

> --
> 2.43.0
>