[PATCH] bus: sunxi-rsb: Fix a small memory leak

[PATCH] bus: sunxi-rsb: Fix a small memory leak

[Dan Carpenter]

The problem is in __devm_regmap_init_sunxi_rsb().  If the call to
__devm_regmap_init() fails, then we leak the "ctx" allocation.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
---
 drivers/bus/sunxi-rsb.c | 10 +---------
 1 file changed, 1 insertion(+), 9 deletions(-)

diff --git a/drivers/bus/sunxi-rsb.c b/drivers/bus/sunxi-rsb.c
index 1b76d9585902..5ec25c8164d1 100644
--- a/drivers/bus/sunxi-rsb.c
+++ b/drivers/bus/sunxi-rsb.c
@@ -417,17 +417,9 @@ static int regmap_sunxi_rsb_reg_write(void *context, unsigned int reg,
 	return sunxi_rsb_write(rdev->rsb, rdev->rtaddr, reg, &val, ctx->size);
 }
 
-static void regmap_sunxi_rsb_free_ctx(void *context)
-{
-	struct sunxi_rsb_ctx *ctx = context;
-
-	kfree(ctx);
-}
-
 static struct regmap_bus regmap_sunxi_rsb = {
 	.reg_write = regmap_sunxi_rsb_reg_write,
 	.reg_read = regmap_sunxi_rsb_reg_read,
-	.free_context = regmap_sunxi_rsb_free_ctx,
 	.reg_format_endian_default = REGMAP_ENDIAN_NATIVE,
 	.val_format_endian_default = REGMAP_ENDIAN_NATIVE,
 };
@@ -446,7 +438,7 @@ static struct sunxi_rsb_ctx *regmap_sunxi_rsb_init_ctx(struct sunxi_rsb_device *
 		return ERR_PTR(-EINVAL);
 	}
 
-	ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
+	ctx = devm_kzalloc(&rdev->dev, sizeof(*ctx), GFP_KERNEL);
 	if (!ctx)
 		return ERR_PTR(-ENOMEM);
 
-- 
2.17.1

Re: [PATCH] bus: sunxi-rsb: Fix a small memory leak

[Chen-Yu Tsai]

Hi,

On Tue, Dec 18, 2018 at 4:28 PM Dan Carpenter <dan.carpenter@oracle.com> wrote:
>
> The problem is in __devm_regmap_init_sunxi_rsb().  If the call to
> __devm_regmap_init() fails, then we leak the "ctx" allocation.

This seems to be the same pattern with regmap implementations that
allocate context data, the other two being:

    - drivers/base/regmap/regmap-mmio.c
    - drivers/bluetooth/btintel.c

(CC-ing Mark) Maybe it's worth fixing in regmap itself?

> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> ---
>  drivers/bus/sunxi-rsb.c | 10 +---------
>  1 file changed, 1 insertion(+), 9 deletions(-)
>
> diff --git a/drivers/bus/sunxi-rsb.c b/drivers/bus/sunxi-rsb.c
> index 1b76d9585902..5ec25c8164d1 100644
> --- a/drivers/bus/sunxi-rsb.c
> +++ b/drivers/bus/sunxi-rsb.c
> @@ -417,17 +417,9 @@ static int regmap_sunxi_rsb_reg_write(void *context, unsigned int reg,
>         return sunxi_rsb_write(rdev->rsb, rdev->rtaddr, reg, &val, ctx->size);
>  }
>
> -static void regmap_sunxi_rsb_free_ctx(void *context)
> -{
> -       struct sunxi_rsb_ctx *ctx = context;
> -
> -       kfree(ctx);
> -}
> -
>  static struct regmap_bus regmap_sunxi_rsb = {
>         .reg_write = regmap_sunxi_rsb_reg_write,
>         .reg_read = regmap_sunxi_rsb_reg_read,
> -       .free_context = regmap_sunxi_rsb_free_ctx,
>         .reg_format_endian_default = REGMAP_ENDIAN_NATIVE,
>         .val_format_endian_default = REGMAP_ENDIAN_NATIVE,
>  };
> @@ -446,7 +438,7 @@ static struct sunxi_rsb_ctx *regmap_sunxi_rsb_init_ctx(struct sunxi_rsb_device *
>                 return ERR_PTR(-EINVAL);
>         }
>
> -       ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
> +       ctx = devm_kzalloc(&rdev->dev, sizeof(*ctx), GFP_KERNEL);

This decouples the lifetime of ctx from the regmap itself. IMO it
would be better to check the return value of __devm_regmap_init()
and act accordingly instead.

ChenYu

>         if (!ctx)
>                 return ERR_PTR(-ENOMEM);
>
> --
> 2.17.1
>