Re: [PATCH] mtd: oxnas_nand: Fix error handling in oxnas_nand_probe()

From: Boris Brezillon
Date: Mon Sep 18 2017 - 06:14:26 EST


Hi Alexey,

On Sat, 9 Sep 2017 01:00:38 +0300
Alexey Khoroshilov <khoroshilov@xxxxxxxxx> wrote:

> oxnas_nand_probe() does not disable clock on error paths.
> The patch adds disabling using devm interface.
>
> Found by Linux Driver Verification project (linuxtesting.org).
>
> Signed-off-by: Alexey Khoroshilov <khoroshilov@xxxxxxxxx>
> ---
> drivers/mtd/nand/oxnas_nand.c | 22 +++++++++++++++-------
> 1 file changed, 15 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/mtd/nand/oxnas_nand.c b/drivers/mtd/nand/oxnas_nand.c
> index 1b207aac840c..8abc69a285dd 100644
> --- a/drivers/mtd/nand/oxnas_nand.c
> +++ b/drivers/mtd/nand/oxnas_nand.c
> @@ -103,16 +103,26 @@ static int oxnas_nand_probe(struct platform_device *pdev)
> if (IS_ERR(oxnas->io_base))
> return PTR_ERR(oxnas->io_base);
>
> - oxnas->clk = devm_clk_get(&pdev->dev, NULL);
> - if (IS_ERR(oxnas->clk))
> - oxnas->clk = NULL;
> -
> /* Only a single chip node is supported */
> count = of_get_child_count(np);
> if (count > 1)
> return -EINVAL;
>
> - clk_prepare_enable(oxnas->clk);
> + oxnas->clk = devm_clk_get(&pdev->dev, NULL);
> + if (IS_ERR(oxnas->clk)) {
> + oxnas->clk = NULL;
> + } else {
> + err = clk_prepare_enable(oxnas->clk);
> + if (err)
> + return err;
> +
> + err = devm_add_action_or_reset(&pdev->dev,
> + (void(*)(void *))clk_disable_unprepare,
> + oxnas->clk);
> + if (err)
> + return err;
> + }
> +

Looks like something that should be made available at the CCF level
either with a devm_clk_get_prepare_enable() or with a
devm_clk_prepare_enable() helper. Would you care proposing this change
to the CCF ML?

In the meantime can you provide a simpler fix that just adds the
missing clk_disable_unprepare() call in the error path?

> device_reset_optional(&pdev->dev);
>
> for_each_child_of_node(np, nand_np) {
> @@ -167,8 +177,6 @@ static int oxnas_nand_remove(struct platform_device *pdev)
> if (oxnas->chips[0])
> nand_release(nand_to_mtd(oxnas->chips[0]));
>
> - clk_disable_unprepare(oxnas->clk);
> -
> return 0;
> }
>