diff --git a/base-foc/src/base/thread/thread.cc b/base-foc/src/base/thread/thread.cc
index e9ceace89..f569c6fc6 100644
--- a/base-foc/src/base/thread/thread.cc
+++ b/base-foc/src/base/thread/thread.cc
@@ -153,6 +153,12 @@ Thread_base::Context *Thread_base::_alloc_context(size_t stack_size)
 	context->stack_base  = ds_addr;
 	context->ds_cap      = ds_cap;
 
+	/*
+	 * The value at the top of the stack might get interpreted as return
+	 * address of the thread start function by GDB, so we set it to 0.
+	 */
+	*(addr_t*)context->stack_top() = 0;
+
 	return context;
 }
 
diff --git a/base-linux/src/base/thread/thread_linux.cc b/base-linux/src/base/thread/thread_linux.cc
index d28cd76b1..94046d1e1 100644
--- a/base-linux/src/base/thread/thread_linux.cc
+++ b/base-linux/src/base/thread/thread_linux.cc
@@ -122,9 +122,7 @@ void Thread_base::start()
 		threadlib_initialized = true;
 	}
 
-	/* align initial stack to 16 byte boundary */
-	void *thread_sp = (void *)((addr_t)(stack_top()) & ~0xf);
-	_tid.tid = lx_create_thread(Thread_base::_thread_start, thread_sp, this);
+	_tid.tid = lx_create_thread(Thread_base::_thread_start, stack_top(), this);
 	_tid.pid = lx_getpid();
 
 	/* wait until the 'thread_start' function got entered */
diff --git a/base-linux/src/platform/x86_32/lx_clone.S b/base-linux/src/platform/x86_32/lx_clone.S
index cc290f656..e162e718b 100644
--- a/base-linux/src/platform/x86_32/lx_clone.S
+++ b/base-linux/src/platform/x86_32/lx_clone.S
@@ -83,8 +83,7 @@ L(thread_start):
     .cfi_startproc;
     /* Clearing frame pointer is insufficient, use CFI.  */
     .cfi_undefined %eip;
-    /* Note: %esi is zero.  */
-    movl    %esi,%ebp   /* terminate the stack frame */
+    xorl    %ebp,%ebp   /* terminate the stack frame */
     call    *%ebx
 #ifdef PIC
     call    L(here)
diff --git a/base-linux/src/platform/x86_64/lx_clone.S b/base-linux/src/platform/x86_64/lx_clone.S
index 8edeea931..35f81b2d9 100644
--- a/base-linux/src/platform/x86_64/lx_clone.S
+++ b/base-linux/src/platform/x86_64/lx_clone.S
@@ -17,6 +17,9 @@
 lx_clone:
 	.cfi_startproc
 
+	/* Align the new stack pointer to 16 bytes. */
+	andq    $0xfffffffffffffff0, %rsi
+
 	/* Insert the argument onto the new stack.  */
 	subq	$16,%rsi
 	movq	%rcx,8(%rsi)
@@ -51,7 +54,7 @@ L(thread_start):
 
 	/* Clear the frame pointer.  The ABI suggests this be done, to mark 
 	   the outermost frame obviously.  */
-	xorl	%ebp, %ebp
+	xorq	%rbp, %rbp
 
 	/* Set up arguments for the function call.  */
 	popq	%rax	/* Function to call.  */
diff --git a/base/include/base/thread.h b/base/include/base/thread.h
index 3dd4f3839..47db0df41 100644
--- a/base/include/base/thread.h
+++ b/base/include/base/thread.h
@@ -100,11 +100,16 @@ namespace Genode {
 				public:
 
 				/**
-				 * Top of stack aligned to 16 byte
+				 * Top of stack
 				 *
-				 * The alignment is also sufficient for the AMD64 ABI.
+				 * The alignment matches an initial stack frame, which is
+				 * sufficient for the AMD64 ABI (stack top + 8 is 16-byte
+				 * aligned).
 				 */
-				addr_t stack_top() const { return (addr_t)_stack & ~0xf; }
+				addr_t stack_top() const
+				{
+					return ((addr_t)_stack & ~0xf) - sizeof(addr_t);
+				}
 
 				/**
 				 * Virtual address of the start of the stack
diff --git a/base/src/base/thread/thread.cc b/base/src/base/thread/thread.cc
index 868b339d2..8c9092689 100644
--- a/base/src/base/thread/thread.cc
+++ b/base/src/base/thread/thread.cc
@@ -153,6 +153,12 @@ Thread_base::Context *Thread_base::_alloc_context(size_t stack_size)
 	context->stack_base  = ds_addr;
 	context->ds_cap      = ds_cap;
 
+	/*
+	 * The value at the top of the stack might get interpreted as return
+	 * address of the thread start function by GDB, so we set it to 0.
+	 */
+	*(addr_t*)context->stack_top() = 0;
+
 	return context;
 }