Re: [PATCH v3] dmaengine: ti: k3-udma-glue: fix NULL dereference in k3_udma_glue_release_rx_chn()

[Frank Li]

On Wed, Aug 12, 2026 at 08:34:26AM +0300, Alexander.Chesnokov@xxxxxxxxxxxxx wrote:
> From: Alexander Chesnokov <Alexander.Chesnokov@xxxxxxxxxxxxx>
>
> If devm_kcalloc() for rx_chn->flows fails in a channel request function,
> the error path calls k3_udma_glue_release_rx_chn(), which dereferences
> the NULL rx_chn->flows pointer in k3_udma_glue_release_rx_flow().
>
> Skip the flow release loop in k3_udma_glue_release_rx_chn() when
> rx_chn->flows is not allocated.
>
> Found by Linux Verification Center (linuxtesting.org) with SVACE.
>
> Fixes: d70241913413 ("dmaengine: ti: k3-udma: Add glue layer for non DMAengine users")
> Cc: stable@xxxxxxxxxxxxxxx
> Reported-by: Pavel Zhigulin <Pavel.Zhigulin@xxxxxxxxxxxxx>
> Signed-off-by: Alexander Chesnokov <Alexander.Chesnokov@xxxxxxxxxxxxx>
> ---

Reviewed-by: Frank Li <Frank.Li@xxxxxxx>

>
> v3: guard the flow release loop in k3_udma_glue_release_rx_chn() instead
> of reordering the flow_num assignment. Covers all error paths in both
> request functions.
> v2: https://lore.kernel.org/all/20251006124258.1132312-1-Pavel.Zhigulin@xxxxxxxxxxxxx/
>
>  drivers/dma/ti/k3-udma-glue.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/dma/ti/k3-udma-glue.c b/drivers/dma/ti/k3-udma-glue.c
> index 4f1aeb81e9c7..a739e60b0764 100644
> --- a/drivers/dma/ti/k3-udma-glue.c
> +++ b/drivers/dma/ti/k3-udma-glue.c
> @@ -1103,8 +1103,9 @@ void k3_udma_glue_release_rx_chn(struct k3_udma_glue_rx_channel *rx_chn)
>  		rx_chn->psil_paired = false;
>  	}
>
> -	for (i = 0; i < rx_chn->flow_num; i++)
> -		k3_udma_glue_release_rx_flow(rx_chn, i);
> +	if (rx_chn->flows)
> +		for (i = 0; i < rx_chn->flow_num; i++)
> +			k3_udma_glue_release_rx_flow(rx_chn, i);
>
>  	if (xudma_rflow_is_gp(rx_chn->common.udmax, rx_chn->flow_id_base))
>  		xudma_free_gp_rflow_range(rx_chn->common.udmax,
> --
> 2.43.0
>