CVE-2024-42319 Information

Description

In the Linux kernel the following vulnerability has been resolved:

mailbox: mtk-cmdq: Move devm_mbox_controller_register() after devm_pm_runtime_enable()

When mtk-cmdq unbinds a WARN_ON message with condition pm_runtime_get_sync() < 0 occurs.

According to the call tracei below: cmdq_mbox_shutdown mbox_free_channel mbox_controller_unregister __devm_mbox_controller_unregister …

The root cause can be deduced to be calling pm_runtime_get_sync() after calling pm_runtime_disable() as observed below:

1. CMDQ driver uses devm_mbox_controller_register() in cmdq_probe() to bind the cmdq device to the mbox_controller so devm_mbox_controller_unregister() will automatically unregister the device bound to the mailbox controller when the device-managed resource is removed. That means devm_mbox_controller_unregister() and cmdq_mbox_shoutdown() will be called after cmdq_remove().
2. CMDQ driver also uses devm_pm_runtime_enable() in cmdq_probe() after devm_mbox_controller_register() so that devm_pm_runtime_disable() will be called after cmdq_remove() but before devm_mbox_controller_unregister().

To fix this problem cmdq_probe() needs to move devm_mbox_controller_register() after devm_pm_runtime_enable() to make devm_pm_runtime_disable() be called after devm_mbox_controller_unregister().

Reference

https://git.kernel.org/stable/c/11fa625b45faf0649118b9deaf2d31c86ac41911 https://git.kernel.org/stable/c/a8bd68e4329f9a0ad1b878733e0f80be6a971649