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.

References

• https://nvd.nist.gov/vuln/detail/CVE-2022-49313
• 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