--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c

@@ -60,6 +60,14 @@ static pud_t bm_pud[PTRS_PER_PUD] __page_aligned_bss __maybe_unused;
 
 static DEFINE_SPINLOCK(swapper_pgdir_lock);
 
+/*
+ * This represents if vmalloc and vmemmap address range overlap with
+ * each other on an intermediate level kernel page table entry which
+ * in turn helps in deciding whether empty kernel page table pages
+ * if any can be freed during memory hotplug operation.
+ */
+static bool vmalloc_vmemmap_overlap;

@@ -770,6 +1022,28 @@ int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node,
 void vmemmap_free(unsigned long start, unsigned long end,
 		struct vmem_altmap *altmap)
 {
+#ifdef CONFIG_MEMORY_HOTPLUG
+	/*
+	 * FIXME: We should have called remove_pagetable(start, end, true).
+	 * vmemmap and vmalloc virtual range might share intermediate kernel
+	 * page table entries. Removing vmemmap range page table pages here
+	 * can potentially conflict with a concurrent vmalloc() allocation.
+	 *
+	 * This is primarily because vmalloc() does not take init_mm ptl for
+	 * the entire page table walk and it's modification. Instead it just
+	 * takes the lock while allocating and installing page table pages
+	 * via [p4d|pud|pmd|pte]_alloc(). A concurrently vanishing page table
+	 * entry via memory hot remove can cause vmalloc() kernel page table
+	 * walk pointers to be invalid on the fly which can cause corruption
+	 * or worst, a crash.
+	 *
+	 * So free_empty_tables() gets called where vmalloc and vmemmap range
+	 * do not overlap at any intermediate level kernel page table entry.
+	 */
+	unmap_hotplug_range(start, end, true);
+	if (!vmalloc_vmemmap_overlap)
+		free_empty_tables(start, end);
+#endif
 }

@@ -1048,10 +1322,18 @@ int p4d_free_pud_page(p4d_t *p4d, unsigned long addr)
 }
 
 #ifdef CONFIG_MEMORY_HOTPLUG
+static void __remove_pgd_mapping(pgd_t *pgdir, unsigned long start, u64 size)
+{
+	unsigned long end = start + size;
+
+	WARN_ON(pgdir != init_mm.pgd);
+	remove_pagetable(start, end, false);
+}