[PATCH 5.12 023/127] platform/x86: dell-smbios-wmi: Fix oops on rmmod dell_smbios

Greg Kroah-Hartman
2021-05-24T16:02:15Z

From: Hans de Goede <hdegoede@redhat.com>

[ Upstream commit 3a53587423d25c87af4b4126a806a0575104b45e ]

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: Sasha Levin <sashal@kernel.org>
---
drivers/platform/x86/dell/dell-smbios-wmi.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/platform/x86/dell/dell-smbios-wmi.c b/drivers/platform/x86/dell/dell-smbios-wmi.c
index 27a298b7c541..c97bd4a45242 100644
--- a/drivers/platform/x86/dell/dell-smbios-wmi.c
+++ b/drivers/platform/x86/dell/dell-smbios-wmi.c
@@ -271,7 +271,8 @@ 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_DEVICE_TABLE(wmi, dell_smbios_wmi_id_table);
--
2.30.2