rusticl/queue: add a life check to prevent applications dead locking

Cc: mesa-stable
Reviewed-by: Adam Jackson <ajax@redhat.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/32821>

src/gallium/frontends/rusticl/core/event.rs

@@ -212,6 +212,14 @@ impl Event {
                 .wait_timeout(lock, Duration::from_secs(1))
                 .unwrap()
                 .0;
+
+            if let Some(queue) = &self.queue {
+                // in case the queue worker thread exited abnormally we'll need to stop spinning on
+                // the cv here, because otherwise we'll end up spinning endlessly.
+                if queue.is_dead() {
+                    return CL_OUT_OF_HOST_MEMORY;
+                }
+            }
         }
         lock.status
     }

src/gallium/frontends/rusticl/core/queue.rs

@@ -88,7 +88,7 @@ pub struct Queue {
     pub props: cl_command_queue_properties,
     pub props_v2: Properties<cl_queue_properties>,
     state: Mutex<QueueState>,
-    _thrd: JoinHandle<()>,
+    thrd: JoinHandle<()>,
 }
 
 impl_cl_type_trait!(cl_command_queue, Queue, CL_INVALID_COMMAND_QUEUE);
@@ -122,7 +122,7 @@ impl Queue {
                 last: Weak::new(),
                 chan_in: tx_q,
             }),
-            _thrd: thread::Builder::new()
+            thrd: thread::Builder::new()
                 .name("rusticl queue thread".into())
                 .spawn(move || {
                     // Track the error of all executed events. This is only needed for in-order
@@ -250,6 +250,10 @@ impl Queue {
         Ok(())
     }
 
+    pub fn is_dead(&self) -> bool {
+        self.thrd.is_finished()
+    }
+
     pub fn is_profiling_enabled(&self) -> bool {
         (self.props & (CL_QUEUE_PROFILING_ENABLE as u64)) != 0
     }