Re: [PATCH v2] platform/x86/amd/pmc: Fix RTC reference leak in amd_pmc_verify_czn_rtc()

[Ilpo Järvinen]

On Tue, 15 Sep 2026, Ma Ke wrote:

> amd_pmc_verify_czn_rtc() opens the RTC with rtc_class_open(), which
> takes both a device reference and a module reference on the RTC
> driver. rtc_class_close() is the matching release, but it is not
> called.
> 
> Use a __free() to cleanup call on the declaration
> 
> Found by code review.
> 
> Fixes: 59348401ebed ("platform/x86: amd-pmc: Add special handling for timer based S0i3 wakeup")
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Ma Ke <make_ruc2021@xxxxxxx>
> ---
> Changes in v2:
> - modified the patch, thanks for developer's suggestions.
> ---
>  drivers/platform/x86/amd/pmc/pmc.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/platform/x86/amd/pmc/pmc.c b/drivers/platform/x86/amd/pmc/pmc.c
> index 6792aa2c6187..b1ad79b22c07 100644
> --- a/drivers/platform/x86/amd/pmc/pmc.c
> +++ b/drivers/platform/x86/amd/pmc/pmc.c
> @@ -14,6 +14,7 @@
>  #include <linux/array_size.h>
>  #include <linux/bitfield.h>
>  #include <linux/bits.h>
> +#include <linux/cleanup.h>
>  #include <linux/debugfs.h>
>  #include <linux/delay.h>
>  #include <linux/dmi.h>
> @@ -646,9 +647,11 @@ static int amd_pmc_wa_irq1(struct amd_pmc_dev *pdev)
>  	return 0;
>  }
>  
> +DEFINE_FREE(rtc_class_close, struct rtc_device *, rtc_class_close(_T));

I'm sorry, I only now realize this is not a local thing at all so it would 
below to the header defining rtc_class_open/close().

More importantly, rtc_class_close() does not handle NULL inputs so 
this DEFINE_FREE() should have the if (_T) boilerplate.

> +
>  static int amd_pmc_verify_czn_rtc(struct amd_pmc_dev *pdev, u32 *arg)
>  {
> -	struct rtc_device *rtc_device;
> +	struct rtc_device *rtc_device __free(rtc_class_close) = NULL;

Please move this to where the actual assignment to rtc_device occurs as 
explained in the long comment in cleanup.h.

>  	time64_t then, now, duration;
>  	struct rtc_wkalrm alarm;
>  	struct rtc_time tm;
> 

-- 
 i.