linux-kernel - [PATCH 5.11 191/254] platform/x86: dell-wmi-sysman: Make it safe to call exit_foo

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Date:   Mon, 29 Mar 2021 09:58:27 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Divya Bharathi <Divya_Bharathi@...l.com>,
        Mario Limonciello <mario.limonciello@...l.com>,
        Hans de Goede <hdegoede@...hat.com>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 5.11 191/254] platform/x86: dell-wmi-sysman: Make it safe to call exit_foo_attributes() multiple times

From: Hans de Goede <hdegoede@...hat.com>

[ Upstream commit 2d0c418c91d8c86a1b9fb254dda842ada9919513 ]

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@...l.com>
Cc: Mario Limonciello <mario.limonciello@...l.com>
Signed-off-by: Hans de Goede <hdegoede@...hat.com>
Link: https://lore.kernel.org/r/20210321115901.35072-4-hdegoede@redhat.com
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/platform/x86/dell-wmi-sysman/enum-attributes.c    | 3 +++
 drivers/platform/x86/dell-wmi-sysman/int-attributes.c     | 3 +++
 drivers/platform/x86/dell-wmi-sysman/passobj-attributes.c | 3 +++
 drivers/platform/x86/dell-wmi-sysman/string-attributes.c  | 3 +++
 4 files changed, 12 insertions(+)

diff --git a/drivers/platform/x86/dell-wmi-sysman/enum-attributes.c b/drivers/platform/x86/dell-wmi-sysman/enum-attributes.c
index 80f4b7785c6c..091e48c217ed 100644
--- a/drivers/platform/x86/dell-wmi-sysman/enum-attributes.c
+++ b/drivers/platform/x86/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-wmi-sysman/int-attributes.c b/drivers/platform/x86/dell-wmi-sysman/int-attributes.c
index 75aedbb733be..8a49ba6e44f9 100644
--- a/drivers/platform/x86/dell-wmi-sysman/int-attributes.c
+++ b/drivers/platform/x86/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-wmi-sysman/passobj-attributes.c b/drivers/platform/x86/dell-wmi-sysman/passobj-attributes.c
index 3abcd95477c0..834b3e82ad9f 100644
--- a/drivers/platform/x86/dell-wmi-sysman/passobj-attributes.c
+++ b/drivers/platform/x86/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-wmi-sysman/string-attributes.c b/drivers/platform/x86/dell-wmi-sysman/string-attributes.c
index ac75dce88a4c..552537852459 100644
--- a/drivers/platform/x86/dell-wmi-sysman/string-attributes.c
+++ b/drivers/platform/x86/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;
 }
-- 
2.30.1