CVE-2022-49313 Information

Description

In the Linux kernel the following vulnerability has been resolved:

drivers: usb: host: Fix deadlock in oxu_bus_suspend()

There is a deadlock in oxu_bus_suspend() which is shown below:

(Thread 1) | (Thread 2) | timer_action() oxu_bus_suspend() | mod_timer() spin_lock_irq() //(1) | (wait a time) … | oxu_watchdog() del_timer_sync() | spin_lock_irq() //(2) (wait timer to stop) | …

We hold oxu->lock in position (1) of thread 1 and use del_timer_sync() to wait timer to stop but timer handler also need oxu->lock in position (2) of thread 2. As a result oxu_bus_suspend() will block forever.

This patch extracts del_timer_sync() from the protection of spin_lock_irq() which could let timer handler to obtain the needed lock.

Reference

https://git.kernel.org/stable/c/2dcec0bc142be2096af71a5703d63237127db204 https://git.kernel.org/stable/c/4187b291a76664a3c03d3f0d9bfadc8322881868 https://git.kernel.org/stable/c/4d378f2ae58138d4c55684e1d274e7dd94aa6524 https://git.kernel.org/stable/c/9b58d255f27b0ed6a2e43208960864d67579db58 https://git.kernel.org/stable/c/a3d380188bde8900c3f604e82b56572896499124 https://git.kernel.org/stable/c/b97aae8b43b718314012e8170b7e03dbfd2e7677 https://git.kernel.org/stable/c/d888753872190abd18f68a7d77b9c7c367f0a7ab https://git.kernel.org/stable/c/f8242044c91cafbba9e320b0fb31abf2429a3221 https://git.kernel.org/stable/c/ffe9440d698274c6462d2e304562c6ddfc8c84df