diff --git a/src/system/kernel/vm/VMKernelAddressSpace.cpp b/src/system/kernel/vm/VMKernelAddressSpace.cpp
index 00605892f8..5806a1ecda 100644
--- a/src/system/kernel/vm/VMKernelAddressSpace.cpp
+++ b/src/system/kernel/vm/VMKernelAddressSpace.cpp
@@ -196,6 +196,7 @@ VMKernelAddressSpace::InsertArea(VMArea* _area, size_t size,
 	TRACE("VMKernelAddressSpace::InsertArea(%p, %" B_PRIu32 ", %#" B_PRIxSIZE
 		", %p \"%s\")\n", addressRestrictions->address,
 		addressRestrictions->address_specification, size, _area, _area->name);
+	ASSERT_WRITE_LOCKED_RW_LOCK(&fLock);
 
 	VMKernelArea* area = static_cast<VMKernelArea*>(_area);
 
@@ -227,6 +228,7 @@ void
 VMKernelAddressSpace::RemoveArea(VMArea* _area, uint32 allocationFlags)
 {
 	TRACE("VMKernelAddressSpace::RemoveArea(%p)\n", _area);
+	ASSERT_WRITE_LOCKED_RW_LOCK(&fLock);
 
 	VMKernelArea* area = static_cast<VMKernelArea*>(_area);
 
diff --git a/src/system/kernel/vm/VMUserAddressSpace.cpp b/src/system/kernel/vm/VMUserAddressSpace.cpp
index 0317b53f6c..e231171e53 100644
--- a/src/system/kernel/vm/VMUserAddressSpace.cpp
+++ b/src/system/kernel/vm/VMUserAddressSpace.cpp
@@ -164,6 +164,8 @@ VMUserAddressSpace::InsertArea(VMArea* _area, size_t size,
 	const virtual_address_restrictions* addressRestrictions,
 	uint32 allocationFlags, void** _address)
 {
+	ASSERT_WRITE_LOCKED_RW_LOCK(&fLock);
+
 	VMUserArea* area = static_cast<VMUserArea*>(_area);
 
 	addr_t searchBase, searchEnd;
@@ -210,6 +212,8 @@ VMUserAddressSpace::InsertArea(VMArea* _area, size_t size,
 void
 VMUserAddressSpace::RemoveArea(VMArea* _area, uint32 allocationFlags)
 {
+	ASSERT_WRITE_LOCKED_RW_LOCK(&fLock);
+
 	VMUserArea* area = static_cast<VMUserArea*>(_area);
 
 	fAreas.Remove(area);