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

Johan Hovold
2025-11-17T16:13:25Z

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)
--
2.51.0