This is a reland of commit 77688e305d
Tests are ignored on some architectures due to the single thread test
issues b/258371694
Original change's description:
> base: unix: add fork_process
>
> The vmm-swap feature will fork a process to run monitoring userfaultfd.
>
> crosvm uses minijail to fork device processes `ProxyDevice::new()`.
>
> Minijail panics on fork if there are any other threads running. The test
> must be executed in a single thread.
>
> design document: go/tanooki-phase1-dd
>
> BUG=b:215093219
> TEST=cargo test -p base -- --test-threads=1
>
> Change-Id: I408dbfa4d606cbe7b2218096b414512710d60100
> Reviewed-on: https://chromium-review.googlesource.com/c/crosvm/crosvm/+/3935683
> Reviewed-by: David Stevens <stevensd@chromium.org>
Bug: b:215093219
Change-Id: I94b912b04947cada3e3332861f18988873dfcf81
Reviewed-on: https://chromium-review.googlesource.com/c/crosvm/crosvm/+/4015626
Reviewed-by: David Stevens <stevensd@chromium.org>
Commit-Queue: David Stevens <stevensd@chromium.org>
Auto-Submit: Shin Kawamura <kawasin@google.com>
741c7cceeb