2022-11-22 12:36:20

by Xiongfeng Wang

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

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 <[email protected]>
---
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

2022-11-23 16:33:19

by Guenter Roeck

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

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 <[email protected]>

Reviewed-by: Guenter Roeck <[email protected]>

> ---
> 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
>