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

Reapply "drm/qxl: simplify qxl_fence_wait"

This reverts commit 07ed11afb68d94eadd4ffc082b97c2331307c5ea.

Stephen Rostedt reports:
 "I went to run my tests on my VMs and the tests hung on boot up.
  Unfortunately, the most I ever got out was:

  [   93.607888] Testing event system initcall: OK
  [   93.667730] Running tests on all trace events:
  [   93.669757] Testing all events: OK
  [   95.631064] ------------[ cut here ]------------
  Timed out after 60 seconds"

and further debugging points to a possible circular locking dependency
between the console_owner locking and the worker pool locking.

Reverting the commit allows Steve's VM to boot to completion again.

[ This may obviously result in the "[TTM] Buffer eviction failed"
  messages again, which was the reason for that original revert. But at
  this point this seems preferable to a non-booting system... ]

kernel.org https://git.kernel.org/stable/c/148ed8b4d64f94ab079c8f0d88c3f444db97ba97 [No types assigned]

kernel.org https://git.kernel.org/stable/c/3628e0383dd349f02f882e612ab6184e4bb3dc10 [No types assigned]

kernel.org https://git.kernel.org/stable/c/3dfe35d8683daf9ba69278643efbabe40000bbf6 [No types assigned]

kernel.org https://git.kernel.org/stable/c/4a89ac4b0921c4ea21eb1b4cf3a469a91bacfcea [No types assigned]

kernel.org https://git.kernel.org/stable/c/b548c53bc3ab83dc6fc86c8e840f013b2032267a [No types assigned]