This is a note to let you know that I've just added the patch titled platform/x86: dell-wmi-sysman: Fix crash caused by calling kset_unregister twice to the 5.11-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: platform-x86-dell-wmi-sysman-fix-crash-caused-by-cal.patch and it can be found in the queue-5.11 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 3ebf30cff473c347db169374502cb6938f3b22c7 Author: Hans de Goede <hdegoede@xxxxxxxxxx> Date: Sun Mar 21 12:58:55 2021 +0100 platform/x86: dell-wmi-sysman: Fix crash caused by calling kset_unregister twice [ Upstream commit d939cd96b9df6dcde1605fab23bbd6307e11f930 ] On some system the WMI GUIDs used by dell-wmi-sysman are present but there are no enum type attributes, this causes init_bios_attributes() to return -ENODEV, after which sysman_init() does a "goto fail_create_group" and then calls release_attributes_data(). release_attributes_data() calls kset_unregister(wmi_priv.main_dir_kset); but before this commit it was missing a "wmi_priv.main_dir_kset = NULL;" statement; and after calling release_attributes_data() the sysman_init() error handling does this: if (wmi_priv.main_dir_kset) { kset_unregister(wmi_priv.main_dir_kset); wmi_priv.main_dir_kset = NULL; } Which causes a second kset_unregister(wmi_priv.main_dir_kset), leading to a double-free, which causes a crash. Add the missing "wmi_priv.main_dir_kset = NULL;" statement to release_attributes_data() to fix this double-free crash. Fixes: e8a60aa7404b ("platform/x86: Introduce support for Systems Management Driver over WMI for Dell Systems") Cc: Divya Bharathi <Divya_Bharathi@xxxxxxxx> Cc: Mario Limonciello <mario.limonciello@xxxxxxxx> Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx> Link: https://lore.kernel.org/r/20210321115901.35072-2-hdegoede@xxxxxxxxxx Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/platform/x86/dell-wmi-sysman/sysman.c b/drivers/platform/x86/dell-wmi-sysman/sysman.c index cb81010ba1a2..c1997db74cca 100644 --- a/drivers/platform/x86/dell-wmi-sysman/sysman.c +++ b/drivers/platform/x86/dell-wmi-sysman/sysman.c @@ -388,6 +388,7 @@ static void release_attributes_data(void) if (wmi_priv.main_dir_kset) { destroy_attribute_objs(wmi_priv.main_dir_kset); kset_unregister(wmi_priv.main_dir_kset); + wmi_priv.main_dir_kset = NULL; } mutex_unlock(&wmi_priv.mutex);