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platform/x86: dell-wmi-sysman: Fix crash caused by calling kset_unregister twice

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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@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
This commit is contained in:
Hans de Goede 2021-03-21 12:58:55 +01:00
parent ec0e8fc416
commit d939cd96b9
1 changed files with 1 additions and 0 deletions
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drivers/platform/x86/dell/dell-wmi-sysman/sysman.c
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@ -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);