virtio-devices, vmm: Shutdown VMM on virtio thread panic

Shutdown the VMM in the virtio (or VMM side of vhost-user) thread
panics.

See: #3031

Signed-off-by: Rob Bradford <robert.bradford@intel.com>

virtio-devices/src/thread_helper.rs

@@ -8,13 +8,18 @@ use crate::{
     ActivateError,
 };
 use seccompiler::{apply_filter, SeccompAction};
-use std::thread::{self, JoinHandle};
+use std::{
+    panic::AssertUnwindSafe,
+    thread::{self, JoinHandle},
+};
+use vmm_sys_util::eventfd::EventFd;
 
 pub(crate) fn spawn_virtio_thread<F>(
     name: &str,
     seccomp_action: &SeccompAction,
     thread_type: Thread,
     epoll_threads: &mut Vec<JoinHandle<()>>,
+    exit_evt: &EventFd,
     f: F,
 ) -> Result<(), ActivateError>
 where
@@ -24,20 +29,31 @@ where
     let seccomp_filter = get_seccomp_filter(seccomp_action, thread_type)
         .map_err(ActivateError::CreateSeccompFilter)?;
 
+    let thread_exit_evt = exit_evt
+        .try_clone()
+        .map_err(ActivateError::CloneExitEventFd)?;
+    let thread_name = name.to_string();
+
     thread::Builder::new()
         .name(name.to_string())
         .spawn(move || {
             if !seccomp_filter.is_empty() {
                 if let Err(e) = apply_filter(&seccomp_filter) {
                     error!("Error applying seccomp filter: {:?}", e);
+                    thread_exit_evt.write(1).ok();
                     return;
                 }
             }
-            f()
+            std::panic::catch_unwind(AssertUnwindSafe(move || f()))
+                .or_else(|_| {
+                    error!("{} thread panicked", thread_name);
+                    thread_exit_evt.write(1)
+                })
+                .ok();
         })
         .map(|thread| epoll_threads.push(thread))
         .map_err(|e| {
             error!("Failed to spawn thread for {}: {}", name, e);
-            ActivateError::BadActivate
+            ActivateError::ThreadSpawn(e)
         })
 }