Fix deadlock involving mmap_sem and memory_range_lock

Change-Id: I187246271163e708af6542c057d0a8dfde5b211e
Fujitsu: TEMP_FIX_1
Refs: #986

kernel/include/process.h

@@ -715,6 +715,8 @@ struct process_vm {
     // 2. addition of process page table (allocate_pages, update_process_page_table)
     // note that physical memory allocator (ihk_mc_alloc_pages, ihk_pagealloc_alloc)
     // is protected by its own lock (see ihk/manycore/generic/page_alloc.c)
+	unsigned long is_memory_range_lock_taken;
+	/* #986: Fix deadlock between do_page_fault_process_vm() and set_host_vma() */
 
 	ihk_atomic_t refcount;
 	int exiting;