fix: allow double dealloc for now(which only occur in drop Frame

discord9 · discord9 · commit f7cf34878151 · 2022-10-20T17:05:27.000+08:00
diff --git a/vm/src/intern.rs b/vm/src/intern.rs
@@ -2,7 +2,8 @@ use crate::{
     builtins::{PyStr, PyStrInterned, PyTypeRef},
     common::lock::PyRwLock,
     convert::ToPyObject,
-    AsObject, Py, PyExact, PyObject, PyObjectRef, PyPayload, PyRef, PyRefExact, VirtualMachine, object::gc::GcObjPtr,
+    object::gc::GcObjPtr,
+    AsObject, Py, PyExact, PyObject, PyObjectRef, PyPayload, PyRef, PyRefExact, VirtualMachine,
 };
 use std::{
     borrow::{Borrow, ToOwned},
diff --git a/vm/src/object/core.rs b/vm/src/object/core.rs
@@ -1083,7 +1083,17 @@ impl PyObject {
         // sanity check
         #[cfg(feature = "gc")]
         {
-            debug_assert!(!ptr.as_ref().header().is_dealloc());
+            if ptr.as_ref().header().is_dealloc() {
+                // it seems dropping a Frame results in double dropping a object
+                error!("is_leaked: {}", ptr.as_ref().header().is_leaked());
+                error!(
+                    "Dropping a already deallocated object!: {:?}",
+                    PyObjectRef { ptr }
+                );
+                error!("{:?}", ptr.as_ref().0.header());
+                error!("Current backtrace: {:?}", backtrace::Backtrace::new());
+            }
+            // debug_assert!(!ptr.as_ref().header().is_dealloc());
 
             if !ptr.as_ref().header().check_set_drop_dealloc() {
                 return;
diff --git a/vm/src/object/gc/collector_sync.rs b/vm/src/object/gc/collector_sync.rs
@@ -153,7 +153,6 @@ impl CcSync {
     }
     pub fn increment(&self, obj: GcObjRef) {
         if obj.header().is_leaked() {
-            // by define a leaked object's rc should not change?
             return;
         }
         obj.header().do_pausing();
@@ -169,13 +168,13 @@ impl CcSync {
             // a leaked object should always keep
             return GcStatus::ShouldKeep;
         }
+
+        // acquire exclusive access to obj's header
+        #[cfg(feature = "threading")]
+        let _lock = obj.header().exclusive.lock();
         // prevent RAII Drop to drop below zero
         if obj.header().rc() > 0 {
             obj.header().do_pausing();
-            // acquire exclusive access to obj's header
-            #[cfg(feature = "threading")]
-            let _lock = obj.header().exclusive.lock();
-
             let rc = obj.header().dec();
             if rc == 0 {
                 self.release(obj)
