| Message ID | 20220302132758.3820-1-xiongx18@fudan.edu.cn |
|---|---|
| State | Changes Requested |
| Headers | show |
| Series | [v3] mtd: rawnand: atmel: fix refcount issue in atmel_nand_controller_init | expand |
On 02.03.2022 15:27, Xin Xiong wrote: > EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe > > 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: f88fc122cc34 ("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> > --- > V2 -> V3: Removed redundant lines > V1 -> V2: Rewrited the error handling block > --- > drivers/mtd/nand/raw/atmel/nand-controller.c | 14 +++++++++++--- > 1 file changed, 11 insertions(+), 3 deletions(-) > > diff --git a/drivers/mtd/nand/raw/atmel/nand-controller.c b/drivers/mtd/nand/raw/atmel/nand-controller.c > index f3276ee9e4fe..3dc4a4bacde5 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_release_dma; > } > > nc->smc = syscon_node_to_regmap(np); > @@ -2074,10 +2076,16 @@ 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->caps->has_dma && !atmel_nand_avoid_dma && nc->dmac) As Boris also suggested previously, checking nc->dmac should be enough here. > + dma_release_channel(nc->dmac); > + > + return ret; > } > > static int > -- > 2.25.1 >
diff --git a/drivers/mtd/nand/raw/atmel/nand-controller.c b/drivers/mtd/nand/raw/atmel/nand-controller.c index f3276ee9e4fe..3dc4a4bacde5 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_release_dma; } nc->smc = syscon_node_to_regmap(np); @@ -2074,10 +2076,16 @@ 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->caps->has_dma && !atmel_nand_avoid_dma && nc->dmac) + dma_release_channel(nc->dmac); + + return ret; } static int
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: f88fc122cc34 ("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> --- V2 -> V3: Removed redundant lines V1 -> V2: Rewrited the error handling block --- drivers/mtd/nand/raw/atmel/nand-controller.c | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-)