Re: [PATCH 07/15] dmaengine: lpc32xx-dmamux: fix device leak on route allocation

Vladimir Zapolskiy
2025-11-17T19:27:17Z

On 11/17/25 18:12, Johan Hovold wrote:
> Make sure to drop the reference taken when looking up the DMA mux
> platform device during route allocation.
>
> Note that holding a reference to a device does not prevent its driver
> data from going away so there is no point in keeping the reference.
>
> Fixes: 5d318b595982 ("dmaengine: Add dma router for pl08x in LPC32XX SoC")
> Cc: stable@vger.kernel.org # 6.12
> Cc: Piotr Wojtaszczyk <piotr.wojtaszczyk@timesys.com>
> Signed-off-by: Johan Hovold <johan@kernel.org>
> ---
> drivers/dma/lpc32xx-dmamux.c | 19 ++++++++++++++-----
> 1 file changed, 14 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/dma/lpc32xx-dmamux.c b/drivers/dma/lpc32xx-dmamux.c
> index 351d7e23e615..33be714740dd 100644
> --- a/drivers/dma/lpc32xx-dmamux.c
> +++ b/drivers/dma/lpc32xx-dmamux.c
> @@ -95,11 +95,12 @@ static void *lpc32xx_dmamux_reserve(struct of_phandle_args *dma_spec,
> struct lpc32xx_dmamux_data *dmamux = platform_get_drvdata(pdev);
> unsigned long flags;
> struct lpc32xx_dmamux *mux = NULL;
> + int ret = -EINVAL;
> int i;
>
> if (dma_spec->args_count != 3) {
> dev_err(&pdev->dev, "invalid number of dma mux args\n");
> - return ERR_PTR(-EINVAL);
> + goto err_put_pdev;
> }
>
> for (i = 0; i < ARRAY_SIZE(lpc32xx_muxes); i++) {
> @@ -111,20 +112,20 @@ static void *lpc32xx_dmamux_reserve(struct of_phandle_args *dma_spec,
> if (!mux) {
> dev_err(&pdev->dev, "invalid mux request number: %d\n",
> dma_spec->args[0]);
> - return ERR_PTR(-EINVAL);
> + goto err_put_pdev;
> }
>
> if (dma_spec->args[2] > 1) {
> dev_err(&pdev->dev, "invalid dma mux value: %d\n",
> dma_spec->args[1]);
> - return ERR_PTR(-EINVAL);
> + goto err_put_pdev;
> }
>
> /* The of_node_put() will be done in the core for the node */
> dma_spec->np = of_parse_phandle(ofdma->of_node, "dma-masters", 0);
> if (!dma_spec->np) {
> dev_err(&pdev->dev, "can't get dma master\n");
> - return ERR_PTR(-EINVAL);
> + goto err_put_pdev;
> }
>
> spin_lock_irqsave(&dmamux->lock, flags);
> @@ -133,7 +134,8 @@ static void *lpc32xx_dmamux_reserve(struct of_phandle_args *dma_spec,
> dev_err(dev, "dma request signal %d busy, routed to %s\n",
> mux->signal, mux->muxval ? mux->name_sel1 : mux->name_sel1);
> of_node_put(dma_spec->np);
> - return ERR_PTR(-EBUSY);
> + ret = -EBUSY;
> + goto err_put_pdev;
> }
>
> mux->busy = true;
> @@ -148,7 +150,14 @@ static void *lpc32xx_dmamux_reserve(struct of_phandle_args *dma_spec,
> dev_dbg(dev, "dma request signal %d routed to %s\n",
> mux->signal, mux->muxval ? mux->name_sel1 : mux->name_sel1);
>
> + put_device(&pdev->dev);
> +
> return mux;
> +
> +err_put_pdev:
> + put_device(&pdev->dev);
> +
> + return ERR_PTR(ret);
> }
>
> static int lpc32xx_dmamux_probe(struct platform_device *pdev)

Reviewed-by: Vladimir Zapolskiy <vz@mleia.com>

--
Best wishes,
Vladimir