[PATCH 0/3] KVM: kvm_create_vm() bug fixes and cleanup

From: Sean Christopherson
Date: Tue Aug 16 2022 - 04:29:02 EST


Fix two (embarassing) bugs in kvm_create_vm() where KVM fails to properly
unwind VM creation, which most often manifests as a not-present page fault
due to use-after-free when walking the global vm_list (VM is added and
freed, but never removed from the list). Patch 3 is a loosely related
clean up.

I discovered the try_get_module() bug by inspection[*]. syzkaller found
the debugfs around the same time.

The try_get_module() bug is especially bad/amusing. The "rmmod --wait"
behavior KVM is trying to handle was removed ~9 years ago...

[*] https://lore.kernel.org/all/YvU+6fdkHaqQiKxp@xxxxxxxxxx

Sean Christopherson (3):
KVM: Properly unwind VM creation if creating debugfs fails
KVM: Unconditionally get a ref to /dev/kvm module when creating a VM
KVM: Move coalesced MMIO initialization (back) into kvm_create_vm()

virt/kvm/kvm_main.c | 39 +++++++++++++++++----------------------
1 file changed, 17 insertions(+), 22 deletions(-)


base-commit: 19a7cc817a380f7a412d7d76e145e9e2bc47e52f
--
2.37.1.595.g718a3a8f04-goog