5 files changed, 30 insertions, 28 deletions
diff --git a/src/qml/jsruntime/qv4context.cpp b/src/qml/jsruntime/qv4context.cpp
index 27c3a31d95..36b1512b63 100644
--- a/src/qml/jsruntime/qv4context.cpp
+++ b/src/qml/jsruntime/qv4context.cpp
@@ -91,9 +91,6 @@ CallContext *ExecutionContext::newCallContext(FunctionObject *function, CallData
 
     c->strictMode = function->strictMode;
     c->outer = function->scope;
-#ifndef QT_NO_DEBUG
-    assert(c->outer->next != (ExecutionContext *)0x1);
-#endif
 
     c->activation = 0;
 
@@ -237,9 +234,6 @@ CallContext::CallContext(ExecutionEngine *engine, ObjectRef qml, FunctionObject
 
     strictMode = true;
     outer = function->scope;
-#ifndef QT_NO_DEBUG
-    assert(outer->next != (ExecutionContext *)0x1);
-#endif
 
     activation = qml.getPointer();
 
diff --git a/src/qml/jsruntime/qv4context_p.h b/src/qml/jsruntime/qv4context_p.h
index 851f024a60..a0930a577e 100644
--- a/src/qml/jsruntime/qv4context_p.h
+++ b/src/qml/jsruntime/qv4context_p.h
@@ -110,7 +110,6 @@ struct Q_QML_EXPORT ExecutionContext : public Managed
     ExecutionContext *outer;
     Lookup *lookups;
     CompiledData::CompilationUnit *compilationUnit;
-    ExecutionContext *next; // used in the GC
 
     struct EvalCode
     {
diff --git a/src/qml/jsruntime/qv4engine.cpp b/src/qml/jsruntime/qv4engine.cpp
index 384254f896..5de8e0de44 100644
--- a/src/qml/jsruntime/qv4engine.cpp
+++ b/src/qml/jsruntime/qv4engine.cpp
@@ -109,21 +109,28 @@ quintptr getStackLimit()
 #  else
     void* stackBottom = 0;
     pthread_attr_t attr;
-    pthread_getattr_np(pthread_self(), &attr);
-    size_t stackSize = 0;
-    pthread_attr_getstack(&attr, &stackBottom, &stackSize);
-    pthread_attr_destroy(&attr);
-
-#    if defined(Q_OS_ANDROID)
-    // Bionic pretends that the main thread has a tiny stack; work around it
-    if (gettid() == getpid()) {
-        rlimit limit;
-        getrlimit(RLIMIT_STACK, &limit);
-        stackBottom = reinterpret_cast<void*>(reinterpret_cast<quintptr>(stackBottom) + stackSize - limit.rlim_cur);
+    if (pthread_getattr_np(pthread_self(), &attr) == 0) {
+        size_t stackSize = 0;
+        pthread_attr_getstack(&attr, &stackBottom, &stackSize);
+        pthread_attr_destroy(&attr);
+
+#        if defined(Q_OS_ANDROID)
+        // Bionic pretends that the main thread has a tiny stack; work around it
+        if (gettid() == getpid()) {
+            rlimit limit;
+            getrlimit(RLIMIT_STACK, &limit);
+            stackBottom = reinterpret_cast<void*>(reinterpret_cast<quintptr>(stackBottom) + stackSize - limit.rlim_cur);
+        }
+#       endif
+
+        stackLimit = reinterpret_cast<quintptr>(stackBottom);
+    } else {
+        int dummy;
+        // this is inexact, as part of the stack is used when being called here,
+        // but let's simply default to 1MB from where the stack is right now
+        stackLimit = reinterpret_cast<qintptr>(&dummy) - 1024*1024;
     }
-#    endif
 
-    stackLimit = reinterpret_cast<quintptr>(stackBottom);
 #  endif
 // This is wrong. StackLimit is the currently committed stack size, not the real end.
 // only way to get that limit is apparently by using VirtualQuery (Yuck)
diff --git a/src/qml/jsruntime/qv4functionobject.cpp b/src/qml/jsruntime/qv4functionobject.cpp
index a1673dfc2a..daa3d5b0de 100644
--- a/src/qml/jsruntime/qv4functionobject.cpp
+++ b/src/qml/jsruntime/qv4functionobject.cpp
@@ -131,9 +131,6 @@ void FunctionObject::init(const StringRef n, bool createProto)
 
     needsActivation = true;
     strictMode = false;
-#ifndef QT_NO_DEBUG
-     assert(scope->next != (ExecutionContext *)0x1);
-#endif
 
     if (createProto) {
         Scoped<Object> proto(s, scope->engine->newObject(scope->engine->protoClass));
diff --git a/src/qml/jsruntime/qv4mm.cpp b/src/qml/jsruntime/qv4mm.cpp
index 625e34de07..d55ddead89 100644
--- a/src/qml/jsruntime/qv4mm.cpp
+++ b/src/qml/jsruntime/qv4mm.cpp
@@ -234,12 +234,17 @@ MemoryManager::MemoryManager()
 #  else
     void* stackBottom = 0;
     pthread_attr_t attr;
-    pthread_getattr_np(pthread_self(), &attr);
-    size_t stackSize = 0;
-    pthread_attr_getstack(&attr, &stackBottom, &stackSize);
-    pthread_attr_destroy(&attr);
+    if (pthread_getattr_np(pthread_self(), &attr) == 0) {
+        size_t stackSize = 0;
+        pthread_attr_getstack(&attr, &stackBottom, &stackSize);
+        pthread_attr_destroy(&attr);
 
-    m_d->stackTop = static_cast<quintptr *>(stackBottom) + stackSize/sizeof(quintptr);
+        m_d->stackTop = static_cast<quintptr *>(stackBottom) + stackSize/sizeof(quintptr);
+    } else {
+        // can't scan the native stack so have to rely on exact gc
+        m_d->stackTop = 0;
+        m_d->exactGC = true;
+    }
 #  endif
 #elif OS(WINCE)
     if (false && g_stackBase) {