]> git.proxmox.com Git - mirror_ubuntu-kernels.git/commit
KVM: kvm_io_bus_unregister_dev() should never fail
authorDavid Hildenbrand <david@redhat.com>
Thu, 23 Mar 2017 17:24:19 +0000 (18:24 +0100)
committerPaolo Bonzini <pbonzini@redhat.com>
Thu, 23 Mar 2017 18:02:25 +0000 (19:02 +0100)
commit90db10434b163e46da413d34db8d0e77404cc645
tree601dc6a684ee2cefe60dcf57ce13dc8472f2511e
parent08d839c4b134b8328ec42f2157a9ca4b93227c03
KVM: kvm_io_bus_unregister_dev() should never fail

No caller currently checks the return value of
kvm_io_bus_unregister_dev(). This is evil, as all callers silently go on
freeing their device. A stale reference will remain in the io_bus,
getting at least used again, when the iobus gets teared down on
kvm_destroy_vm() - leading to use after free errors.

There is nothing the callers could do, except retrying over and over
again.

So let's simply remove the bus altogether, print an error and make
sure no one can access this broken bus again (returning -ENOMEM on any
attempt to access it).

Fixes: e93f8a0f821e ("KVM: convert io_bus to SRCU")
Cc: stable@vger.kernel.org # 3.4+
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
include/linux/kvm_host.h
virt/kvm/eventfd.c
virt/kvm/kvm_main.c