diff --git a/src/core/thread.d b/src/core/thread.d
index 4f99cbbc31..e050c1c553 100644
--- a/src/core/thread.d
+++ b/src/core/thread.d
@@ -2073,9 +2073,9 @@ extern (C) bool thread_isMainThread() nothrow @nogc
  *
  *       extern (C) void rt_moduleTlsCtor();
  */
-extern (C) Thread thread_attachThis()
+extern (C) Thread thread_attachThis() nothrow
 {
-    GC.disable(); scope(exit) GC.enable();
+    GC.disable(); scope(success) GC.enable();
 
     if (auto t = Thread.getThis())
         return t;
diff --git a/src/gc/impl/conservative/gc.d b/src/gc/impl/conservative/gc.d
index 10726554a0..7582380efa 100644
--- a/src/gc/impl/conservative/gc.d
+++ b/src/gc/impl/conservative/gc.d
@@ -259,12 +259,12 @@ class ConservativeGC : GC
 
     import core.internal.spinlock;
     static gcLock = shared(AlignedSpinLock)(SpinLock.Contention.lengthy);
-    static bool _inFinalizer;
+    static bool _isLocked;
 
     // lock GC, throw InvalidMemoryOperationError on recursive locking during finalization
     static void lockNR() @nogc nothrow
     {
-        if (_inFinalizer)
+        if (_isLocked)
             onInvalidMemoryOperationError();
         gcLock.lock();
     }
@@ -817,7 +817,7 @@ class ConservativeGC : GC
 
     void free(void *p) nothrow
     {
-        if (!p || _inFinalizer)
+        if (!p || _isLocked)
         {
             return;
         }
@@ -1093,7 +1093,7 @@ class ConservativeGC : GC
 
     void removeRange(void *p) nothrow @nogc
     {
-        if (!p)
+        if (!p || _isLocked)
         {
             return;
         }
@@ -1120,7 +1120,7 @@ class ConservativeGC : GC
 
     bool inFinalizer() nothrow
     {
-        return _inFinalizer;
+        return _isLocked;
     }
 
 
@@ -1500,8 +1500,8 @@ struct Gcx
      */
     void runFinalizers(in void[] segment) nothrow
     {
-        ConservativeGC._inFinalizer = true;
-        scope (failure) ConservativeGC._inFinalizer = false;
+        ConservativeGC._isLocked = true;
+        scope (failure) ConservativeGC._isLocked = false;
 
         foreach (pool; pooltable[0 .. npools])
         {
@@ -1518,7 +1518,7 @@ struct Gcx
                 spool.runFinalizers(segment);
             }
         }
-        ConservativeGC._inFinalizer = false;
+        ConservativeGC._isLocked = false;
     }
 
     Pool* findPool(void* p) pure nothrow
@@ -2374,12 +2374,14 @@ struct Gcx
 
         {
             // lock roots and ranges around suspending threads b/c they're not reentrant safe
+            ConservativeGC._isLocked = true;
             rangesLock.lock();
             rootsLock.lock();
             scope (exit)
             {
                 rangesLock.unlock();
                 rootsLock.unlock();
+                ConservativeGC._isLocked = false;
             }
             thread_suspendAll();
 
@@ -2395,6 +2397,7 @@ struct Gcx
             markAll(nostack);
 
             thread_processGCMarks(&isMarked);
+            ConservativeGC._isLocked = false;
             thread_resumeAll();
         }
 
@@ -2408,12 +2411,12 @@ struct Gcx
             start = stop;
         }
 
-        ConservativeGC._inFinalizer = true;
+        ConservativeGC._isLocked = true;
         size_t freedLargePages=void;
         {
-            scope (failure) ConservativeGC._inFinalizer = false;
+            scope (failure) ConservativeGC._isLocked = false;
             freedLargePages = sweep();
-            ConservativeGC._inFinalizer = false;
+            ConservativeGC._isLocked = false;
         }
 
         if (config.profile)