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: e8a60aa7 ("platform/x86: Introduce support for Systems Management Driver over WMI for Dell Systems") Cc: Divya Bharathi <Divya_Bharathi@dell.com> Cc: Mario Limonciello <mario.limonciello@dell.com> Signed-off-by:Hans de Goede <hdegoede@redhat.com> Link: https://lore.kernel.org/r/20210321115901.35072-2-hdegoede@redhat.com
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