3 files changed, 22 insertions, 10 deletions

diff --git a/arch/x86/include/asm/pgtable_64.h b/arch/x86/include/asm/pgtable_64.h
index 5be9063545d2..809abb335627 100644
--- a/arch/x86/include/asm/pgtable_64.h
+++ b/arch/x86/include/asm/pgtable_64.h
@@ -115,7 +115,8 @@ static inline void native_pgd_clear(pgd_t *pgd)
         native_set_pgd(pgd, native_make_pgd(0));
 }
 
-extern void sync_global_pgds(unsigned long start, unsigned long end);
+extern void sync_global_pgds(unsigned long start, unsigned long end,
+                             int removed);
 
 /*
  * Conversion functions: convert a page and protection to a page entry,
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index a24194681513..d393ac669cc0 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -350,7 +350,7 @@ out:
 
 void vmalloc_sync_all(void)
 {
-        sync_global_pgds(VMALLOC_START & PGDIR_MASK, VMALLOC_END);
+        sync_global_pgds(VMALLOC_START & PGDIR_MASK, VMALLOC_END, 0);
 }
 
 /*
diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index 0e996c0a7eff..529625118ff6 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -178,7 +178,7 @@ __setup("noexec32=", nonx32_setup);
  * When memory was added/removed make sure all the processes MM have
  * suitable PGD entries in the local PGD level page.
  */
-void sync_global_pgds(unsigned long start, unsigned long end)
+void sync_global_pgds(unsigned long start, unsigned long end, int removed)
 {
         unsigned long address;
 
@@ -186,7 +186,12 @@ void sync_global_pgds(unsigned long start, unsigned long end)
                 const pgd_t *pgd_ref = pgd_offset_k(address);
                 struct page *page;
 
-                if (pgd_none(*pgd_ref))
+                /*
+                 * When it is called after memory hot remove, pgd_none()
+                 * returns true. In this case (removed == 1), we must clear
+                 * the PGD entries in the local PGD level page.
+                 */
+                if (pgd_none(*pgd_ref) && !removed)
                         continue;
 
                 spin_lock(&pgd_lock);
@@ -199,12 +204,18 @@ void sync_global_pgds(unsigned long start, unsigned long end)
                         pgt_lock = &pgd_page_get_mm(page)->page_table_lock;
                         spin_lock(pgt_lock);
 
-                        if (pgd_none(*pgd))
-                                set_pgd(pgd, *pgd_ref);
-                        else
+                        if (!pgd_none(*pgd_ref) && !pgd_none(*pgd))
                                 BUG_ON(pgd_page_vaddr(*pgd)
                                        != pgd_page_vaddr(*pgd_ref));
 
+                        if (removed) {
+                                if (pgd_none(*pgd_ref) && !pgd_none(*pgd))
+                                        pgd_clear(pgd);
+                        } else {
+                                if (pgd_none(*pgd))
+                                        set_pgd(pgd, *pgd_ref);
+                        }
+
                         spin_unlock(pgt_lock);
                 }
                 spin_unlock(&pgd_lock);
@@ -633,7 +644,7 @@ kernel_physical_mapping_init(unsigned long start,
         }
 
         if (pgd_changed)
-                sync_global_pgds(addr, end - 1);
+                sync_global_pgds(addr, end - 1, 0);
 
         __flush_tlb_all();
 
@@ -995,7 +1006,7 @@ remove_pagetable(unsigned long start, unsigned long end, bool direct)
         }
 
         if (pgd_changed)
-                sync_global_pgds(start, end - 1);
+                sync_global_pgds(start, end - 1, 1);
 
         flush_tlb_all();
 }
@@ -1342,7 +1353,7 @@ int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node)
         else
                 err = vmemmap_populate_basepages(start, end, node);
         if (!err)
-                sync_global_pgds(start, end - 1);
+                sync_global_pgds(start, end - 1, 0);
         return err;
 }