| Message ID | 20220127084104.3683-1-xiongx18@fudan.edu.cn |
|---|---|
| State | Superseded |
| Headers | show |
| Series | mtd: rawnand: atmel: fix refcount issue in atmel_nand_controller_init | expand |
Hi Xin, xiongx18@fudan.edu.cn wrote on Thu, 27 Jan 2022 16:41:05 +0800: > 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> > --- > drivers/mtd/nand/raw/atmel/nand-controller.c | 18 +++++++++++++++--- > 1 file changed, 15 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..7003877632fb 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 +2076,20 @@ 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) { > + if (!IS_ERR_OR_NULL(nc->dmac)) { if (!nc->dmac) { > + dma_release_channel(nc->dmac); > + nc->dmac = NULL; This is then unnecessary and the whole block and the two first checks can then be ignored as dmac will not be set otherwise (and will stay NULL). > + } > + } > + > + return ret; > } > > static int Thanks, Miquèl
diff --git a/drivers/mtd/nand/raw/atmel/nand-controller.c b/drivers/mtd/nand/raw/atmel/nand-controller.c index f3276ee9e4fe..7003877632fb 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 +2076,20 @@ 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) { + if (!IS_ERR_OR_NULL(nc->dmac)) { + dma_release_channel(nc->dmac); + nc->dmac = NULL; + } + } + + 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> --- drivers/mtd/nand/raw/atmel/nand-controller.c | 18 +++++++++++++++--- 1 file changed, 15 insertions(+), 3 deletions(-)