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platform/x86/amd/pmc: Fix RTC reference leak in amd_pmc_verify_czn_rtc()

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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. The matching release is rtc_class_close(), and it is never
called. Every return path after the device has been opened, the ones
that return 0 as well as the ones that report an error, leaves both
references behind, so each S0i3 suspend leaks them.

Release the reference with a __free() cleanup on the declaration,
which covers every return path without adding labels.

rtc_class_close() does not accept a NULL argument, so the cleanup
helper has to guard against one: rtc_class_open() may fail and the
declaration still has to be cleaned up.

Found by code review.

Fixes: 59348401eb ("platform/x86: amd-pmc: Add special handling for timer based S0i3 wakeup")
Cc: stable@vger.kernel.org
Signed-off-by: Ma Ke <make_ruc2021@163.com>
Reviewed-by: Mario Limonciello (AMD) <superm1@kernel.org>
Link: https://patch.msgid.link/20261011121759.3267678-1-make_ruc2021@163.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
This commit is contained in:
Ma Ke 2026-10-11 20:17:58 +08:00 committed by Alexandre Belloni
parent 3784706c87
commit 22b9306f1f
2 changed files with 5 additions and 2 deletions
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5
drivers/platform/x86/amd/pmc/pmc.c
View File

@ -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>
@ -648,7 +649,6 @@ static int amd_pmc_wa_irq1(struct amd_pmc_dev *pdev)
static int amd_pmc_verify_czn_rtc(struct amd_pmc_dev *pdev, u32 *arg)
{
struct rtc_device *rtc_device;
time64_t then, now, duration;
struct rtc_wkalrm alarm;
struct rtc_time tm;
@ -664,7 +664,8 @@ static int amd_pmc_verify_czn_rtc(struct amd_pmc_dev *pdev, u32 *arg)
if (pdev->major < 64 || (pdev->major == 64 && pdev->minor < 53))
return 0;
rtc_device = rtc_class_open("rtc0");
struct rtc_device *rtc_device __free(rtc_class_close) =
rtc_class_open("rtc0");
if (!rtc_device)
return 0;
rc = rtc_read_next_alarm(rtc_device, &alarm);

2
include/linux/rtc.h
View File

@ -13,6 +13,7 @@
#define _LINUX_RTC_H_
#include <linux/cleanup.h>
#include <linux/types.h>
#include <linux/interrupt.h>
#include <linux/nvmem-provider.h>
@ -201,6 +202,7 @@ extern void rtc_update_irq(struct rtc_device *rtc,
extern struct rtc_device *rtc_class_open(const char *name);
extern void rtc_class_close(struct rtc_device *rtc);
DEFINE_FREE(rtc_class_close, struct rtc_device *, if (_T) rtc_class_close(_T));
extern int rtc_irq_set_state(struct rtc_device *rtc, int enabled);
extern int rtc_irq_set_freq(struct rtc_device *rtc, int freq);