2 files changed, 14 insertions, 6 deletions
diff --git a/src/thread.cc b/src/thread.cc
index c771c5b173..e1de92d0d0 100644
--- a/src/thread.cc
+++ b/src/thread.cc
@@ -373,7 +373,6 @@ void Thread::InitStackHwm() {
     PLOG(FATAL) << "pthread_getattr_np failed";
   }
 
-  // stack_base is the "lowest addressable byte" of the stack.
   void* stack_base;
   size_t stack_size;
   errno = pthread_attr_getstack(&attributes, &stack_base, &stack_size);
@@ -385,7 +384,15 @@ void Thread::InitStackHwm() {
   if (stack_size <= kStackOverflowReservedBytes) {
     LOG(FATAL) << "attempt to attach a thread with a too-small stack (" << stack_size << " bytes)";
   }
-  stack_hwm_ = reinterpret_cast<byte*>(stack_base) + stack_size - kStackOverflowReservedBytes;
+
+  // stack_base is the "lowest addressable byte" of the stack.
+  // Our stacks grow down, so we want stack_end_ to be near there, but reserving enough room
+  // to throw a StackOverflowError.
+  stack_end_ = reinterpret_cast<byte*>(stack_base) - kStackOverflowReservedBytes;
+
+  // Sanity check.
+  int stack_variable;
+  CHECK_GT(&stack_variable, (void*) stack_end_);
 
   errno = pthread_attr_destroy(&attributes);
   if (errno != 0) {
diff --git a/src/thread.h b/src/thread.h
index b9df711325..6095407b48 100644
--- a/src/thread.h
+++ b/src/thread.h
@@ -410,8 +410,8 @@ class Thread {
     return ThreadOffset(OFFSETOF_MEMBER(Thread, state_));
   }
 
-  static ThreadOffset StackHwmOffset() {
-    return ThreadOffset(OFFSETOF_MEMBER(Thread, stack_hwm_));
+  static ThreadOffset StackEndOffset() {
+    return ThreadOffset(OFFSETOF_MEMBER(Thread, stack_end_));
   }
 
   static ThreadOffset JniEnvOffset() {
@@ -475,8 +475,9 @@ class Thread {
   // FIXME: placeholder for the gc cardTable
   uint32_t card_table_;
 
-  // The high water mark for this thread's stack.
-  byte* stack_hwm_;
+  // The end of this thread's stack. This is the lowest safely-addressable address on the stack.
+  // We leave extra space so there's room for the code that throws StackOverflowError.
+  byte* stack_end_;
 
   // Top of the managed stack, written out prior to the state transition from
   // kRunnable to kNative. Uses include to give the starting point for scanning