platform/x86: dell-wmi-sysman: Make it safe to call exit_foo_attributes() multiple...

During some of the error-exit paths it is possible that
release_attributes_data() will get called multiple times,
which results in exit_foo_attributes() getting called multiple
times.

Make it safe to call exit_foo_attributes() multiple times,
avoiding double-free()s in this case.

Note that release_attributes_data() really should only be called
once during error-exit paths. This will be fixed in a separate patch
and it is good to have the exit_foo_attributes() functions modified
this way regardless.

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/20210321115901.35072-4-hdegoede@redhat.com

diff --git a/drivers/platform/x86/dell/dell-wmi-sysman/enum-attributes.c b/drivers/platform/x86/dell/dell-wmi-sysman/enum-attributes.c
index 80f4b77..091e48c 100644 (file)
--- a/drivers/platform/x86/dell/dell-wmi-sysman/enum-attributes.c
+++ b/drivers/platform/x86/dell/dell-wmi-sysman/enum-attributes.c
@@ -185,5 +185,8 @@ void exit_enum_attributes(void)
                        sysfs_remove_group(wmi_priv.enumeration_data[instance_id].attr_name_kobj,
                                                                &enumeration_attr_group);
        }
+       wmi_priv.enumeration_instances_count = 0;
+
        kfree(wmi_priv.enumeration_data);
+       wmi_priv.enumeration_data = NULL;
 }

diff --git a/drivers/platform/x86/dell/dell-wmi-sysman/int-attributes.c b/drivers/platform/x86/dell/dell-wmi-sysman/int-attributes.c
index 75aedbb..8a49ba6 100644 (file)
--- a/drivers/platform/x86/dell/dell-wmi-sysman/int-attributes.c
+++ b/drivers/platform/x86/dell/dell-wmi-sysman/int-attributes.c
@@ -175,5 +175,8 @@ void exit_int_attributes(void)
                        sysfs_remove_group(wmi_priv.integer_data[instance_id].attr_name_kobj,
                                                                &integer_attr_group);
        }
+       wmi_priv.integer_instances_count = 0;
+
        kfree(wmi_priv.integer_data);
+       wmi_priv.integer_data = NULL;
 }

diff --git a/drivers/platform/x86/dell/dell-wmi-sysman/passobj-attributes.c b/drivers/platform/x86/dell/dell-wmi-sysman/passobj-attributes.c
index 3abcd95..834b3e8 100644 (file)
--- a/drivers/platform/x86/dell/dell-wmi-sysman/passobj-attributes.c
+++ b/drivers/platform/x86/dell/dell-wmi-sysman/passobj-attributes.c
@@ -183,5 +183,8 @@ void exit_po_attributes(void)
                        sysfs_remove_group(wmi_priv.po_data[instance_id].attr_name_kobj,
                                                                &po_attr_group);
        }
+       wmi_priv.po_instances_count = 0;
+
        kfree(wmi_priv.po_data);
+       wmi_priv.po_data = NULL;
 }

diff --git a/drivers/platform/x86/dell/dell-wmi-sysman/string-attributes.c b/drivers/platform/x86/dell/dell-wmi-sysman/string-attributes.c
index ac75dce..5525378 100644 (file)
--- a/drivers/platform/x86/dell/dell-wmi-sysman/string-attributes.c
+++ b/drivers/platform/x86/dell/dell-wmi-sysman/string-attributes.c
@@ -155,5 +155,8 @@ void exit_str_attributes(void)
                        sysfs_remove_group(wmi_priv.str_data[instance_id].attr_name_kobj,
                                                                &str_attr_group);
        }
+       wmi_priv.str_instances_count = 0;
+
        kfree(wmi_priv.str_data);
+       wmi_priv.str_data = NULL;
 }