In the Linux kernel, the following vulnerability has been resolved:

driver core: Fix wait_for_device_probe() & deferred_probe_timeout interaction

Mounting NFS rootfs was timing out when deferred_probe_timeout was
non-zero [1].  This was because ip_auto_config() initcall times out
waiting for the network interfaces to show up when
deferred_probe_timeout was non-zero. While ip_auto_config() calls
wait_for_device_probe() to make sure any currently running deferred
probe work or asynchronous probe finishes, that wasn't sufficient to
account for devices being deferred until deferred_probe_timeout.

Commit 35a672363ab3 ("driver core: Ensure wait_for_device_probe() waits
until the deferred_probe_timeout fires") tried to fix that by making
sure wait_for_device_probe() waits for deferred_probe_timeout to expire
before returning.

However, if wait_for_device_probe() is called from the kernel_init()
context:

- Before deferred_probe_initcall() [2], it causes the boot process to
  hang due to a deadlock.

- After deferred_probe_initcall() [3], it blocks kernel_init() from
  continuing till deferred_probe_timeout expires and beats the point of
  deferred_probe_timeout that's trying to wait for userspace to load
  modules.

Neither of this is good. So revert the changes to
wait_for_device_probe().

[1] - https://lore.kernel.org/lkml/TYAPR01MB45443DF63B9EF29054F7C41FD8C60@TYAPR01MB4544.jpnprd01.prod.outlook.com/
[2] - https://lore.kernel.org/lkml/[email protected]/
[3] - https://lore.kernel.org/lkml/[email protected]/

https://git.kernel.org/stable/c/29357883a89193863f3cc6a2c5e0b42ceb022761

https://git.kernel.org/stable/c/4ad6af07efcca85369c21e4897b3020cff2c170b

https://git.kernel.org/stable/c/528229474e1cbb1b3451cb713d94aecb5f6ee264

https://git.kernel.org/stable/c/5ee76c256e928455212ab759c51d198fedbe7523

https://git.kernel.org/stable/c/71cbce75031aed26c72c2dc8a83111d181685f1b