Messages in this thread | | | Date | Mon, 31 Jan 2022 17:16:06 +0100 | From | Miquel Raynal <> | Subject | Re: [PATCH] mtd: rawnand: atmel: fix refcount issue in atmel_nand_controller_init |
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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
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