Patch "rtc: cmos: Disable ACPI RTC event on removal" has been added to the 5.4-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    rtc: cmos: Disable ACPI RTC event on removal

to the 5.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     rtc-cmos-disable-acpi-rtc-event-on-removal.patch
and it can be found in the queue-5.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 206c1090d35d5c5f0e864b6d690149560273c0ab
Author: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
Date:   Wed Nov 9 13:15:36 2022 +0100

    rtc: cmos: Disable ACPI RTC event on removal
    
    [ Upstream commit 83ebb7b3036d151ee39a4a752018665648fc3bd4 ]
    
    Make cmos_do_remove() drop the ACPI RTC fixed event handler so as to
    prevent it from operating on stale data in case the event triggers
    after driver removal.
    
    Fixes: 311ee9c151ad ("rtc: cmos: allow using ACPI for RTC alarm instead of HPET")
    Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
    Reviewed-by: Zhang Rui <rui.zhang@xxxxxxxxx>
    Tested-by: Zhang Rui <rui.zhang@xxxxxxxxx>
    Reviewed-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
    Link: https://lore.kernel.org/r/2224609.iZASKD2KPV@kreacher
    Signed-off-by: Alexandre Belloni <alexandre.belloni@xxxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/rtc/rtc-cmos.c b/drivers/rtc/rtc-cmos.c
index 203f41afe8c1..636d6ef45481 100644
--- a/drivers/rtc/rtc-cmos.c
+++ b/drivers/rtc/rtc-cmos.c
@@ -752,6 +752,14 @@ static void acpi_rtc_event_setup(struct device *dev)
 	acpi_disable_event(ACPI_EVENT_RTC, 0);
 }
 
+static void acpi_rtc_event_cleanup(void)
+{
+	if (acpi_disabled)
+		return;
+
+	acpi_remove_fixed_event_handler(ACPI_EVENT_RTC, rtc_handler);
+}
+
 static void rtc_wake_on(struct device *dev)
 {
 	acpi_clear_event(ACPI_EVENT_RTC);
@@ -838,6 +846,10 @@ static inline void acpi_rtc_event_setup(struct device *dev)
 {
 }
 
+static inline void acpi_rtc_event_cleanup(void)
+{
+}
+
 static inline void acpi_cmos_wake_setup(struct device *dev)
 {
 }
@@ -1085,6 +1097,9 @@ static void cmos_do_remove(struct device *dev)
 			hpet_unregister_irq_handler(cmos_interrupt);
 	}
 
+	if (!dev_get_platdata(dev))
+		acpi_rtc_event_cleanup();
+
 	cmos->rtc = NULL;
 
 	ports = cmos->iomem;