[PATCH] i2c: npcm7xx: Fix error handling in npcm_i2c_init()

[PATCH] i2c: npcm7xx: Fix error handling in npcm_i2c_init()

[Yuan Can]

A problem about i2c-npcm7xx create debugfs failed is triggered with the
following log given:

 [  173.827310] debugfs: Directory 'npcm_i2c' with parent '/' already present!

The reason is that npcm_i2c_init() returns platform_driver_register()
directly without checking its return value, if platform_driver_register()
failed, it returns without destroy the newly created debugfs, resulting
the debugfs of npcm_i2c can never be created later.

 npcm_i2c_init()
   debugfs_create_dir() # create debugfs directory
   platform_driver_register()
     driver_register()
       bus_add_driver()
         priv = kzalloc(...) # OOM happened
   # return without destroy debugfs directory

Fix by removing debugfs when platform_driver_register() returns error.

Fixes: 56a1485b102e ("i2c: npcm7xx: Add Nuvoton NPCM I2C controller driver")
Signed-off-by: Yuan Can <yuancan@huawei.com>
---
 drivers/i2c/busses/i2c-npcm7xx.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/drivers/i2c/busses/i2c-npcm7xx.c b/drivers/i2c/busses/i2c-npcm7xx.c
index 0c365b57d957..83457359ec45 100644
--- a/drivers/i2c/busses/i2c-npcm7xx.c
+++ b/drivers/i2c/busses/i2c-npcm7xx.c
@@ -2393,8 +2393,17 @@ static struct platform_driver npcm_i2c_bus_driver = {
 
 static int __init npcm_i2c_init(void)
 {
+	int ret;
+
 	npcm_i2c_debugfs_dir = debugfs_create_dir("npcm_i2c", NULL);
-	return platform_driver_register(&npcm_i2c_bus_driver);
+
+	ret = platform_driver_register(&npcm_i2c_bus_driver);
+	if (ret) {
+		debugfs_remove_recursive(npcm_i2c_debugfs_dir);
+		return ret;
+	}
+
+	return 0;
 }
 module_init(npcm_i2c_init);
 
-- 
2.17.1

Re: [PATCH] i2c: npcm7xx: Fix error handling in npcm_i2c_init()

[Tali Perry]

On Wed, Nov 9, 2022 at 1:24 PM Yuan Can <yuancan@huawei.com> wrote:
>
> A problem about i2c-npcm7xx create debugfs failed is triggered with the
> following log given:
>
>  [  173.827310] debugfs: Directory 'npcm_i2c' with parent '/' already present!
>
> The reason is that npcm_i2c_init() returns platform_driver_register()
> directly without checking its return value, if platform_driver_register()
> failed, it returns without destroy the newly created debugfs, resulting
> the debugfs of npcm_i2c can never be created later.
>
>  npcm_i2c_init()
>    debugfs_create_dir() # create debugfs directory
>    platform_driver_register()
>      driver_register()
>        bus_add_driver()
>          priv = kzalloc(...) # OOM happened
>    # return without destroy debugfs directory
>
> Fix by removing debugfs when platform_driver_register() returns error.
>
> Fixes: 56a1485b102e ("i2c: npcm7xx: Add Nuvoton NPCM I2C controller driver")
> Signed-off-by: Yuan Can <yuancan@huawei.com>
> ---
>  drivers/i2c/busses/i2c-npcm7xx.c | 11 ++++++++++-
>  1 file changed, 10 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/i2c/busses/i2c-npcm7xx.c b/drivers/i2c/busses/i2c-npcm7xx.c
> index 0c365b57d957..83457359ec45 100644
> --- a/drivers/i2c/busses/i2c-npcm7xx.c
> +++ b/drivers/i2c/busses/i2c-npcm7xx.c
> @@ -2393,8 +2393,17 @@ static struct platform_driver npcm_i2c_bus_driver = {
>
>  static int __init npcm_i2c_init(void)
>  {
> +       int ret;
> +
>         npcm_i2c_debugfs_dir = debugfs_create_dir("npcm_i2c", NULL);
> -       return platform_driver_register(&npcm_i2c_bus_driver);
> +
> +       ret = platform_driver_register(&npcm_i2c_bus_driver);
> +       if (ret) {
> +               debugfs_remove_recursive(npcm_i2c_debugfs_dir);
> +               return ret;
> +       }
> +
> +       return 0;
>  }
>  module_init(npcm_i2c_init);
>
> --
> 2.17.1
>

Thanks Yuan!

Reviewed-by: Tali Perry <tali.perry@nuvoton.com>

Re: [PATCH] i2c: npcm7xx: Fix error handling in npcm_i2c_init()

[Wolfram Sang]

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On Wed, Nov 09, 2022 at 11:22:50AM +0000, Yuan Can wrote:
> A problem about i2c-npcm7xx create debugfs failed is triggered with the
> following log given:
> 
>  [  173.827310] debugfs: Directory 'npcm_i2c' with parent '/' already present!
> 
> The reason is that npcm_i2c_init() returns platform_driver_register()
> directly without checking its return value, if platform_driver_register()
> failed, it returns without destroy the newly created debugfs, resulting
> the debugfs of npcm_i2c can never be created later.
> 
>  npcm_i2c_init()
>    debugfs_create_dir() # create debugfs directory
>    platform_driver_register()
>      driver_register()
>        bus_add_driver()
>          priv = kzalloc(...) # OOM happened
>    # return without destroy debugfs directory
> 
> Fix by removing debugfs when platform_driver_register() returns error.
> 
> Fixes: 56a1485b102e ("i2c: npcm7xx: Add Nuvoton NPCM I2C controller driver")
> Signed-off-by: Yuan Can <yuancan@huawei.com>

Applied to for-current, thanks!


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