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Subject[PATCH] mtd: rawnand: atmel: fix refcount leaks in atmel_nand_controller_init
Date
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
increased earlier by dma_request_channel(), which may cause refcount
leaks. What's more, the "nc->mck" object also needs to be handled
correctly.

Fix it by adding specific error handling code in those error paths.

Signed-off-by: Xin Xiong <xiongx18@fudan.edu.cn>
Signed-off-by: Xiyu Yang <xiyuyang19@fudan.edu.cn>
Signed-off-by: Xin Tan <tanxin.ctf@gmail.com>
---
drivers/mtd/nand/raw/atmel/nand-controller.c | 22 +++++++++++++++++---
1 file changed, 19 insertions(+), 3 deletions(-)

diff --git a/drivers/mtd/nand/raw/atmel/nand-controller.c b/drivers/mtd/nand/raw/atmel/nand-controller.c
index f3276ee9e..b3801ebd2 100644
--- a/drivers/mtd/nand/raw/atmel/nand-controller.c
+++ b/drivers/mtd/nand/raw/atmel/nand-controller.c
@@ -2060,13 +2060,15 @@ 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_put_clk;
}

nc->smc = syscon_node_to_regmap(np);
@@ -2074,10 +2076,24 @@ 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_put_clk;
}

return 0;
+
+out_put_clk:
+ clk_put(nc->mck);
+ nc->mck = NULL;
+
+out_release_dma:
+ if (nc->caps->has_dma && !atmel_nand_avoid_dma) {
+ if (!IS_ERR_OR_NULL(nc->dmac)) {
+ dma_release_channel(nc->dmac);
+ nc->dmac = NULL;
+ }
+ }
+
+ return ret;
}

static int
--
2.25.1
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