A guest can trigger unplugging 9pfs server's virtio-pci device via ACPI
eject. As a consequence the device is unrealized, server's internal state
is freed while pending coroutines would still have access to them, causing
a potential heap-use-after-free.

Overview Patches:

 - Patch 1: this is the core fix, that drains all PDUs (i.e. coroutines
   that handle individual pending requests in parallel) before freeing
   server state.

 - Patch 2: fixes a similar identified issue with the Xen transport, even
   though not triggered via ACPI, it is also prone to UAF, plus a resource
   leak.

v2:
  - Patch 1: Make Jia the official author of this patch.
  - Drop prev. patch 2 ("hw/9pfs/virtio: disable hotpluggable property...")
  - Patch 2: defer explict xen_9pfs_disconnect() call from error paths of
    xen_9pfs_pdu_vmarshal() and xen_9pfs_pdu_vunmarshal().

Christian Schoenebeck (1):
  hw/9pfs/xen: drain in-flight PDUs before xen-9p disconnect

Jia Jia (1):
  hw/9pfs/virtio: drain in-flight PDUs before virtio-9p unrealize

 hw/9pfs/virtio-9p-device.c |  1 +
 hw/9pfs/xen-9p-backend.c   | 19 +++++++++++++++++--
 2 files changed, 18 insertions(+), 2 deletions(-)

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2.47.3