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

KVM: SVM: Flush pages under kvm->lock to fix UAF in svm_register_enc_region()

Do the cache flush of converted pages in svm_register_enc_region() before
dropping kvm->lock to fix use-after-free issues where region and/or its
array of pages could be freed by a different task, e.g. if userspace has
__unregister_enc_region_locked() already queued up for the region.

Note, the "obvious" alternative of using local variables doesn't fully
resolve the bug, as region->pages is also dynamically allocated.  I.e. the
region structure itself would be fine, but region->pages could be freed.

Flushing multiple pages under kvm->lock is unfortunate, but the entire
flow is a rare slow path, and the manual flush is only needed on CPUs that
lack coherency for encrypted memory.

kernel.org https://git.kernel.org/stable/c/12f8e32a5a389a5d58afc67728c76e61beee1ad4 [No types assigned]

kernel.org https://git.kernel.org/stable/c/2d13b79640b147bd77c34a5998533b2021a4122d [No types assigned]

kernel.org https://git.kernel.org/stable/c/4868c0ecdb6cfde7c70cf478c46e06bb9c7e5865 [No types assigned]

kernel.org https://git.kernel.org/stable/c/5ef1d8c1ddbf696e47b226e11888eaf8d9e8e807 [No types assigned]

kernel.org https://git.kernel.org/stable/c/e126b508ed2e616d679d85fca2fbe77bb48bbdd7 [No types assigned]

kernel.org https://git.kernel.org/stable/c/f6d53d8a2617dd58c89171a6b9610c470ebda38a [No types assigned]