diff --git a/kernel/arch/x86_64/PageTable.cpp b/kernel/arch/x86_64/PageTable.cpp
index 11ee3923..df499313 100644
--- a/kernel/arch/x86_64/PageTable.cpp
+++ b/kernel/arch/x86_64/PageTable.cpp
@@ -866,7 +866,7 @@ namespace Kernel
 			last_address -= rem;
 
 		ASSERT(is_canonical(first_address));
-		ASSERT(is_canonical(last_address));
+		ASSERT(is_canonical(last_address - 1));
 		const vaddr_t uc_vaddr_start = uncanonicalize(first_address);
 		const vaddr_t uc_vaddr_end   = uncanonicalize(last_address);
 
@@ -948,7 +948,7 @@ namespace Kernel
 			last_address -= rem;
 
 		ASSERT(is_canonical(first_address));
-		ASSERT(is_canonical(last_address));
+		ASSERT(is_canonical(last_address - 1));
 
 		SpinLockGuard _(m_lock);
 
diff --git a/kernel/include/kernel/Memory/Types.h b/kernel/include/kernel/Memory/Types.h
index acc33320..6a1673d8 100644
--- a/kernel/include/kernel/Memory/Types.h
+++ b/kernel/include/kernel/Memory/Types.h
@@ -4,7 +4,7 @@
 
 #if ARCH(x86_64)
 	#define KERNEL_OFFSET 0xFFFFFFFF80000000
-	#define USERSPACE_END 0xFFFF800000000000
+	#define USERSPACE_END 0x800000000000
 #elif ARCH(i686)
 	#define KERNEL_OFFSET 0xC0000000
 	#define USERSPACE_END 0xC0000000