From 3a53587423d25c87af4b4126a806a0575104b45e Mon Sep 17 00:00:00 2001
From: Hans de Goede <hdegoede@redhat.com>
Date: Tue, 18 May 2021 14:50:27 +0200
Subject: [PATCH] platform/x86: dell-smbios-wmi: Fix oops on rmmod dell_smbios
Git-commit: 3a53587423d25c87af4b4126a806a0575104b45e
References: git-fixes
Patch-mainline: v5.13-rc3

init_dell_smbios_wmi() only registers the dell_smbios_wmi_driver on systems
where the Dell WMI interface is supported. While exit_dell_smbios_wmi()
unregisters it unconditionally, this leads to the following oops:

[  175.722921] ------------[ cut here ]------------
[  175.722925] Unexpected driver unregister!
[  175.722939] WARNING: CPU: 1 PID: 3630 at drivers/base/driver.c:194 driver_unregister+0x38/0x40
...
[  175.723089] Call Trace:
[  175.723094]  cleanup_module+0x5/0xedd [dell_smbios]
...
[  175.723148] ---[ end trace 064c34e1ad49509d ]---

Make the unregister happen on the same condition the register happens
to fix this.

Cc: Mario Limonciello <mario.limonciello@outlook.com>
Fixes: 1a258e670434 ("platform/x86: dell-smbios-wmi: Add new WMI dispatcher driver")
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Mario Limonciello <mario.limonciello@outlook.com>
Reviewed-by: Mark Gross <mgross@linux.intel.com>
Link: https://lore.kernel.org/r/20210518125027.21824-1-hdegoede@redhat.com
Signed-off-by: Oliver Neukum <oneukum@suse.com>
---
 drivers/platform/x86/dell-smbios-wmi.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/drivers/platform/x86/dell-smbios-wmi.c
+++ b/drivers/platform/x86/dell-smbios-wmi.c
@@ -274,7 +274,8 @@ int init_dell_smbios_wmi(void)
 
 void exit_dell_smbios_wmi(void)
 {
-	wmi_driver_unregister(&dell_smbios_wmi_driver);
+	if (wmi_supported)
+		wmi_driver_unregister(&dell_smbios_wmi_driver);
 }
 
 MODULE_ALIAS("wmi:" DELL_WMI_SMBIOS_GUID);