From d939cd96b9df6dcde1605fab23bbd6307e11f930 Mon Sep 17 00:00:00 2001 From: Hans de Goede Date: Sun, 21 Mar 2021 12:58:55 +0100 Subject: [PATCH] platform/x86: dell-wmi-sysman: Fix crash caused by calling kset_unregister twice 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 Cc: Mario Limonciello Signed-off-by: Hans de Goede Link: https://lore.kernel.org/r/20210321115901.35072-2-hdegoede@redhat.com --- drivers/platform/x86/dell/dell-wmi-sysman/sysman.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/platform/x86/dell/dell-wmi-sysman/sysman.c b/drivers/platform/x86/dell/dell-wmi-sysman/sysman.c index cb81010ba1a2..c1997db74cca 100644 --- a/drivers/platform/x86/dell/dell-wmi-sysman/sysman.c +++ b/drivers/platform/x86/dell/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); -- 2.11.0