linux-kernel - Re: [PATCH 06/15] dmaengine: lpc18xx-dmamux: fix device leak on route allocation

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <2e38039b-f136-44c6-829c-1d98783bbb1a@mleia.com>
Date: Mon, 17 Nov 2025 21:24:48 +0200
From: Vladimir Zapolskiy <vz@...ia.com>
To: Johan Hovold <johan@...nel.org>, Vinod Koul <vkoul@...nel.org>
Cc: Ludovic Desroches <ludovic.desroches@...rochip.com>,
 Viresh Kumar <vireshk@...nel.org>,
 Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
 Vinicius Costa Gomes <vinicius.gomes@...el.com>,
 Dave Jiang <dave.jiang@...el.com>,
 Piotr Wojtaszczyk <piotr.wojtaszczyk@...esys.com>,
 Amélie Delaunay <amelie.delaunay@...s.st.com>,
 Maxime Coquelin <mcoquelin.stm32@...il.com>,
 Alexandre Torgue <alexandre.torgue@...s.st.com>,
 Peter Ujfalusi <peter.ujfalusi@...il.com>, dmaengine@...r.kernel.org,
 linux-kernel@...r.kernel.org, stable@...r.kernel.org
Subject: Re: [PATCH 06/15] dmaengine: lpc18xx-dmamux: fix device leak on route
 allocation

Hi Johan.

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: e5f4ae84be74 ("dmaengine: add driver for lpc18xx dmamux")
> Cc: stable@...r.kernel.org	# 4.3
> Signed-off-by: Johan Hovold <johan@...nel.org>
> ---
>   drivers/dma/lpc18xx-dmamux.c | 19 ++++++++++++++-----
>   1 file changed, 14 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/dma/lpc18xx-dmamux.c b/drivers/dma/lpc18xx-dmamux.c
> index 2b6436f4b193..d3ff521951b8 100644
> --- a/drivers/dma/lpc18xx-dmamux.c
> +++ b/drivers/dma/lpc18xx-dmamux.c
> @@ -57,30 +57,31 @@ static void *lpc18xx_dmamux_reserve(struct of_phandle_args *dma_spec,
>   	struct lpc18xx_dmamux_data *dmamux = platform_get_drvdata(pdev);
>   	unsigned long flags;
>   	unsigned mux;
> +	int ret = -EINVAL;
>   
>   	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;
>   	}
>   
>   	mux = dma_spec->args[0];
>   	if (mux >= dmamux->dma_master_requests) {
>   		dev_err(&pdev->dev, "invalid mux number: %d\n",
>   			dma_spec->args[0]);
> -		return ERR_PTR(-EINVAL);
> +		goto err_put_pdev;
>   	}
>   
>   	if (dma_spec->args[1] > LPC18XX_DMAMUX_MAX_VAL) {
>   		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);
> @@ -89,7 +90,8 @@ static void *lpc18xx_dmamux_reserve(struct of_phandle_args *dma_spec,
>   		dev_err(&pdev->dev, "dma request %u busy with %u.%u\n",
>   			mux, mux, dmamux->muxes[mux].value);
>   		of_node_put(dma_spec->np);
> -		return ERR_PTR(-EBUSY);
> +		ret = -EBUSY;
> +		goto err_put_pdev;
>   	}
>   
>   	dmamux->muxes[mux].busy = true;
> @@ -106,7 +108,14 @@ static void *lpc18xx_dmamux_reserve(struct of_phandle_args *dma_spec,
>   	dev_dbg(&pdev->dev, "mapping dmamux %u.%u to dma request %u\n", mux,
>   		dmamux->muxes[mux].value, mux);
>   
> +	put_device(&pdev->dev);
> +
>   	return &dmamux->muxes[mux];
> +
> +err_put_pdev:
> +	put_device(&pdev->dev);
> +
> +	return ERR_PTR(ret);
>   }
>   
>   static int lpc18xx_dmamux_probe(struct platform_device *pdev)

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

-- 
Best wishes,
Vladimir