rt: Take the task lock when dropping port refcounts

Sucks, but otherwise there are races when one task drops the refcount to zero
followed by another bumping it again

1 files changed, 3 insertions, 1 deletions

diff --git a/src/rt/rust_builtin.cpp b/src/rt/rust_builtin.cpp
index 30b915f4e96..e8109ea7a04 100644
--- a/src/rt/rust_builtin.cpp
+++ b/src/rt/rust_builtin.cpp
@@ -471,6 +471,7 @@ extern "C" CDECL void
 del_port(rust_port *port) {
     rust_task *task = rust_scheduler::get_task();
     LOG(task, comm, "del_port(0x%" PRIxPTR ")", (uintptr_t) port);
+    scoped_lock with(task->lock);
     port->deref();
 }
 
@@ -487,11 +488,12 @@ chan_id_send(type_desc *t, rust_task_id target_task_id,
     rust_task *target_task = task->kernel->get_task_by_id(target_task_id);
     if(target_task) {
         rust_port *port = target_task->get_port_by_id(target_port_id);
-        target_task->deref();
         if(port) {
             port->send(sptr);
+            scoped_lock with(target_task->lock);
             port->deref();
         }
+        target_task->deref();
     }
 }