[PATCH] watchdog: sp5100_tco: Fix PCI device refcount leak

[PATCH] watchdog: sp5100_tco: Fix PCI device refcount leak

[Xiongfeng Wang]

for_each_pci_dev() is implemented by pci_get_device(). The comment of
pci_get_device() says that it will increase the reference count for the
returned pci_dev and also decrease the reference count for the input
pci_dev @from if it is not NULL.

If we break out for_each_pci_dev() loop with pdev not NULL, we need to
call pci_dev_put() to decrease the reference count. Add the missing
pci_dev_put() in error path of sp5100_tco_init() and also when we unload
module.

Fixes: 15e28bf13008 ("watchdog: Add support for sp5100 chipset TCO")
Signed-off-by: Xiongfeng Wang <wangxiongfeng2@huawei.com>
---
 drivers/watchdog/sp5100_tco.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/watchdog/sp5100_tco.c b/drivers/watchdog/sp5100_tco.c
index fb426b7d81da..f00f26f90444 100644
--- a/drivers/watchdog/sp5100_tco.c
+++ b/drivers/watchdog/sp5100_tco.c
@@ -599,7 +599,7 @@ static int __init sp5100_tco_init(void)
 
 	err = platform_driver_register(&sp5100_tco_driver);
 	if (err)
-		return err;
+		goto put_dev;
 
 	sp5100_tco_platform_device =
 		platform_device_register_simple(TCO_DRIVER_NAME, -1, NULL, 0);
@@ -612,6 +612,8 @@ static int __init sp5100_tco_init(void)
 
 unreg_platform_driver:
 	platform_driver_unregister(&sp5100_tco_driver);
+put_dev:
+	pci_dev_put(sp5100_tco_pci);
 	return err;
 }
 
@@ -619,6 +621,7 @@ static void __exit sp5100_tco_exit(void)
 {
 	platform_device_unregister(sp5100_tco_platform_device);
 	platform_driver_unregister(&sp5100_tco_driver);
+	pci_dev_put(sp5100_tco_pci);
 }
 
 module_init(sp5100_tco_init);
-- 
2.20.1

Re: [PATCH] watchdog: sp5100_tco: Fix PCI device refcount leak

[Guenter Roeck]

On Tue, Nov 22, 2022 at 07:56:51PM +0800, Xiongfeng Wang wrote:
> for_each_pci_dev() is implemented by pci_get_device(). The comment of
> pci_get_device() says that it will increase the reference count for the
> returned pci_dev and also decrease the reference count for the input
> pci_dev @from if it is not NULL.
> 
> If we break out for_each_pci_dev() loop with pdev not NULL, we need to
> call pci_dev_put() to decrease the reference count. Add the missing
> pci_dev_put() in error path of sp5100_tco_init() and also when we unload
> module.
> 
> Fixes: 15e28bf13008 ("watchdog: Add support for sp5100 chipset TCO")
> Signed-off-by: Xiongfeng Wang <wangxiongfeng2@huawei.com>

Reviewed-by: Guenter Roeck <linux@roeck-us.net>

> ---
>  drivers/watchdog/sp5100_tco.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/watchdog/sp5100_tco.c b/drivers/watchdog/sp5100_tco.c
> index fb426b7d81da..f00f26f90444 100644
> --- a/drivers/watchdog/sp5100_tco.c
> +++ b/drivers/watchdog/sp5100_tco.c
> @@ -599,7 +599,7 @@ static int __init sp5100_tco_init(void)
>  
>  	err = platform_driver_register(&sp5100_tco_driver);
>  	if (err)
> -		return err;
> +		goto put_dev;
>  
>  	sp5100_tco_platform_device =
>  		platform_device_register_simple(TCO_DRIVER_NAME, -1, NULL, 0);
> @@ -612,6 +612,8 @@ static int __init sp5100_tco_init(void)
>  
>  unreg_platform_driver:
>  	platform_driver_unregister(&sp5100_tco_driver);
> +put_dev:
> +	pci_dev_put(sp5100_tco_pci);
>  	return err;
>  }
>  
> @@ -619,6 +621,7 @@ static void __exit sp5100_tco_exit(void)
>  {
>  	platform_device_unregister(sp5100_tco_platform_device);
>  	platform_driver_unregister(&sp5100_tco_driver);
> +	pci_dev_put(sp5100_tco_pci);
>  }
>  
>  module_init(sp5100_tco_init);
> -- 
> 2.20.1
>