linux-kernel - [PATCH 1/2] thermal: netlink: Improve the initcall ordering

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Message-Id: <20200717164217.18819-1-daniel.lezcano@linaro.org>
Date:   Fri, 17 Jul 2020 18:42:16 +0200
From:   Daniel Lezcano <daniel.lezcano@...aro.org>
To:     daniel.lezcano@...aro.org, rui.zhang@...el.com
Cc:     linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org,
        m.szyprowski@...sung.com, amit.kucheria@...aro.org
Subject: [PATCH 1/2] thermal: netlink: Improve the initcall ordering

The initcalls like to play joke. In our case, the thermal-netlink
initcall is called after the thermal-core initcall but this one sends
a notification before the former is initialzed. No issue was spotted,
but it could lead to a memory corruption, so instead of relying on the
core_initcall for the thermal-netlink, let's initialize directly from
the thermal-core init routine, so we have full control of the init
ordering.

Reported-by: Marek Szyprowski <m.szyprowski@...sung.com>
Tested-by: Marek Szyprowski <m.szyprowski@...sung.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@...aro.org>
---
 drivers/thermal/thermal_core.c    | 4 ++++
 drivers/thermal/thermal_netlink.c | 3 +--
 drivers/thermal/thermal_netlink.h | 6 ++++++
 3 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c
index 25ef29123f72..c2e7d7aaa354 100644
--- a/drivers/thermal/thermal_core.c
+++ b/drivers/thermal/thermal_core.c
@@ -1581,6 +1581,10 @@ static int __init thermal_init(void)
 {
 	int result;
 
+	result = thermal_netlink_init();
+	if (result)
+		goto error;
+
 	mutex_init(&poweroff_lock);
 	result = thermal_register_governors();
 	if (result)
diff --git a/drivers/thermal/thermal_netlink.c b/drivers/thermal/thermal_netlink.c
index dd0a3b889674..42eace7401da 100644
--- a/drivers/thermal/thermal_netlink.c
+++ b/drivers/thermal/thermal_netlink.c
@@ -641,8 +641,7 @@ static struct genl_family thermal_gnl_family __ro_after_init = {
 	.n_mcgrps	= ARRAY_SIZE(thermal_genl_mcgrps),
 };
 
-static int __init thermal_netlink_init(void)
+int __init thermal_netlink_init(void)
 {
 	return genl_register_family(&thermal_gnl_family);
 }
-core_initcall(thermal_netlink_init);
diff --git a/drivers/thermal/thermal_netlink.h b/drivers/thermal/thermal_netlink.h
index 0ec28d105da5..828d1dddfa98 100644
--- a/drivers/thermal/thermal_netlink.h
+++ b/drivers/thermal/thermal_netlink.h
@@ -6,6 +6,7 @@
 
 /* Netlink notification function */
 #ifdef CONFIG_THERMAL_NETLINK
+int __init thermal_netlink_init(void);
 int thermal_notify_tz_create(int tz_id, const char *name);
 int thermal_notify_tz_delete(int tz_id);
 int thermal_notify_tz_enable(int tz_id);
@@ -23,6 +24,11 @@ int thermal_notify_cdev_delete(int cdev_id);
 int thermal_notify_tz_gov_change(int tz_id, const char *name);
 int thermal_genl_sampling_temp(int id, int temp);
 #else
+static inline int thermal_netlink_init(void)
+{
+	return 0;
+}
+
 static inline int thermal_notify_tz_create(int tz_id, const char *name)
 {
 	return 0;
-- 
2.17.1