diff --git a/include/asm-powerpc/processor.h b/include/asm-powerpc/processor.h
index cf83f2d7e2a5dea90b550861b3b0502c54853551..a1deed85f31d087dd87f9f2bc8b8269e73c2d308 100644
--- a/include/asm-powerpc/processor.h
+++ b/include/asm-powerpc/processor.h
@@ -81,6 +81,10 @@ extern struct task_struct *last_task_used_altivec;
 extern struct task_struct *last_task_used_spe;
 
 #ifdef CONFIG_PPC32
+
+#if CONFIG_TASK_SIZE > CONFIG_KERNEL_START
+#error User TASK_SIZE overlaps with KERNEL_START address
+#endif
 #define TASK_SIZE	(CONFIG_TASK_SIZE)
 
 /* This decides where the kernel will search for a free chunk of vm