Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
From:   "Rafael J. Wysocki" <rjw@rjwysocki.net>
To:     Alexandre Belloni <alexandre.belloni@bootlin.com>,
        linux-rtc@vger.kernel.org
Cc:     Linux ACPI <linux-acpi@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Linux PM <linux-pm@vger.kernel.org>,
        Zhang Rui <rui.zhang@intel.com>,
        Alessandro Zummo <a.zummo@towertech.it>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        Bjorn Helgaas <helgaas@kernel.org>
Subject: [PATCH v2 5/5] rtc: rtc-cmos: Disable ACPI RTC event on removal
Date:   Wed, 09 Nov 2022 13:15:36 +0100
Message-ID: <2224609.iZASKD2KPV@kreacher>
In-Reply-To: <5640233.DvuYhMxLoT@kreacher>
References: <5640233.DvuYhMxLoT@kreacher>
MIME-Version: 1.0
Content-Transfer-Encoding: 7Bit
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

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@intel.com>
---

v1 -> v2:
   * Do not clear the driver data pointer (the driver core does that) (Andy)
   * Adjust the code pattern in acpi_rtc_event_cleanup() (Andy)
   * Drop inline from the full definition of acpi_rtc_event_cleanup()

---
 drivers/rtc/rtc-cmos.c |   15 +++++++++++++++
 1 file changed, 15 insertions(+)

Index: linux-pm/drivers/rtc/rtc-cmos.c
===================================================================
--- linux-pm.orig/drivers/rtc/rtc-cmos.c
+++ linux-pm/drivers/rtc/rtc-cmos.c
@@ -798,6 +798,14 @@ static void acpi_rtc_event_setup(struct
 	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);
@@ -884,6 +892,10 @@ static inline void acpi_rtc_event_setup(
 {
 }
 
+static inline void acpi_rtc_event_cleanup(void)
+{
+}
+
 static inline void acpi_cmos_wake_setup(struct device *dev)
 {
 }
@@ -1138,6 +1150,9 @@ static void cmos_do_remove(struct device
 			hpet_unregister_irq_handler(cmos_interrupt);
 	}
 
+	if (!dev_get_platdata(dev))
+		acpi_rtc_event_cleanup();
+
 	cmos->rtc = NULL;
 
 	ports = cmos->iomem;