commit f18e116c007d054f83ca5bf261c48696556f329a
author David Brazdil <dbrazdil@google.com> Sun Dec 18 18:27:23 2022 +0000
committer David Brazdil <dbrazdil@google.com> Sun Dec 18 23:13:44 2022 +0000
tree c7df0e74582724fdac39f0b62c875f64adba9df4
parent 146bfc12f94aaf87ea8a01e00aad49404a453fbe

virtualizationservice: Fix race in monitor_vm_exit

monitor_vm_exit() runs in a detached thread, waiting for an instance of
crosvm to exit. When it does, it cleans up after it and submits
telemetry to statsd.

However, there is currently no guarantee that the thread will get to
complete its task. If exit() is called, eg. because there are no
remaining clients of the service, the thread is interrupted and
terminated together with the rest of the process. Whether it completes
its job or not therefore can depend on the delay between the last
VirtualMachine reference is dropped and LazyServiceGuard terminating
the process.

Fix this race by joining the monitor_vm_exit as the VirtualMachine
object is dropped. This prevents the process from exiting until the
thread has completed.

Bug: 245727626
Test: atest -p packages/modules/Virtualization:avf-presubmit
Change-Id: Iefbd4181a8ca95bbb3a4fed0f85d9929d081ff73