Commit 9b08d211 authored Mar 04, 2022 by Xin Xiong Committed by Greg Kroah-Hartman Apr 15, 2022

mtd: rawnand: atmel: fix refcount issue in atmel_nand_controller_init



[ Upstream commit fecbd4a317c95d73c849648c406bcf1b6a0ec1cf ]

The reference counting issue happens in several error handling paths
on a refcounted object "nc->dmac". In these paths, the function simply
returns the error code, forgetting to balance the reference count of
"nc->dmac", increased earlier by dma_request_channel(), which may
cause refcount leaks.

Fix it by decrementing the refcount of specific object in those error
paths.

Fixes: f88fc122 ("mtd: nand: Cleanup/rework the atmel_nand driver")
Co-developed-by: Xiyu Yang <xiyuyang19@fudan.edu.cn>
Signed-off-by: Xiyu Yang <xiyuyang19@fudan.edu.cn>
Co-developed-by: Xin Tan <tanxin.ctf@gmail.com>
Signed-off-by: Xin Tan <tanxin.ctf@gmail.com>
Signed-off-by: Xin Xiong <xiongx18@fudan.edu.cn>
Reviewed-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20220304085330.3610-1-xiongx18@fudan.edu.cn


Signed-off-by: Sasha Levin <sashal@kernel.org>

parent 443121c9

drivers/mtd/nand/raw/atmel/nand-controller.c

+11 −3

Original line number	Diff line number	Diff line
		@@ -2004,13 +2004,15 @@ static int atmel_nand_controller_init(struct atmel_nand_controller *nc,
		nc->mck = of_clk_get(dev->parent->of_node, 0);
		if (IS_ERR(nc->mck)) {
		dev_err(dev, "Failed to retrieve MCK clk\n");
		return PTR_ERR(nc->mck);
		ret = PTR_ERR(nc->mck);
		goto out_release_dma;
		}

		np = of_parse_phandle(dev->parent->of_node, "atmel,smc", 0);
		if (!np) {
		dev_err(dev, "Missing or invalid atmel,smc property\n");
		return -EINVAL;
		ret = -EINVAL;
		goto out_release_dma;
		}

		nc->smc = syscon_node_to_regmap(np);
		@@ -2018,10 +2020,16 @@ static int atmel_nand_controller_init(struct atmel_nand_controller *nc,
		if (IS_ERR(nc->smc)) {
		ret = PTR_ERR(nc->smc);
		dev_err(dev, "Could not get SMC regmap (err = %d)\n", ret);
		return ret;
		goto out_release_dma;
		}

		return 0;

		out_release_dma:
		if (nc->dmac)
		dma_release_channel(nc->dmac);

		return ret;
		}

		static int