diff --git a/xen/arch/x86/domain.c b/xen/arch/x86/domain.c
index 8d579e2cf9..93cda1ccdd 100644
--- a/xen/arch/x86/domain.c
+++ b/xen/arch/x86/domain.c
@@ -995,13 +995,13 @@ int arch_set_info_guest(
             {
                 struct page_info *page = page_list_remove_head(&d->page_list);
 
-                if ( page_lock(page) )
+                if ( page_lock(page, 1) )
                 {
                     if ( (page->u.inuse.type_info & PGT_type_mask) ==
                          PGT_l4_page_table )
                         done = !fill_ro_mpt(page_to_mfn(page));
 
-                    page_unlock(page);
+                    page_unlock(page, 1);
                 }
 
                 page_list_add_tail(page, &d->page_list);
diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c
index a88cd9ce7c..ff734e362c 100644
--- a/xen/arch/x86/mm.c
+++ b/xen/arch/x86/mm.c
@@ -2030,11 +2030,12 @@ static inline bool current_locked_page_ne_check(struct page_info *page) {
 #define current_locked_page_ne_check(x) true
 #endif
 
-int page_lock(struct page_info *page)
+int page_lock(struct page_info *page, bool lock_check)
 {
     unsigned long x, nx;
 
-    ASSERT(current_locked_page_check(NULL));
+    if ( lock_check )
+        ASSERT(current_locked_page_check(NULL));
 
     do {
         while ( (x = page->u.inuse.type_info) & PGT_locked )
@@ -2051,11 +2052,12 @@ int page_lock(struct page_info *page)
     return 1;
 }
 
-void page_unlock(struct page_info *page)
+void page_unlock(struct page_info *page, bool lock_check)
 {
     unsigned long x, nx, y = page->u.inuse.type_info;
 
-    ASSERT(current_locked_page_check(page));
+    if ( lock_check )
+        ASSERT(current_locked_page_check(page));
 
     do {
         x = y;
@@ -3897,7 +3899,7 @@ long do_mmu_update(
             }
             va = _p(((unsigned long)va & PAGE_MASK) + (req.ptr & ~PAGE_MASK));
 
-            if ( page_lock(page) )
+            if ( page_lock(page, 1) )
             {
                 switch ( page->u.inuse.type_info & PGT_type_mask )
                 {
@@ -3954,7 +3956,7 @@ long do_mmu_update(
                         rc = 0;
                     break;
                 }
-                page_unlock(page);
+                page_unlock(page, 1);
                 if ( rc == -EINTR )
                     rc = -ERESTART;
             }
@@ -4247,7 +4249,7 @@ static int __do_update_va_mapping(
     if ( unlikely(!gl1pg) )
         goto out;
 
-    if ( !page_lock(gl1pg) )
+    if ( !page_lock(gl1pg, 1) )
     {
         put_page(gl1pg);
         goto out;
@@ -4255,7 +4257,7 @@ static int __do_update_va_mapping(
 
     if ( (gl1pg->u.inuse.type_info & PGT_type_mask) != PGT_l1_page_table )
     {
-        page_unlock(gl1pg);
+        page_unlock(gl1pg, 1);
         put_page(gl1pg);
         goto out;
     }
@@ -4263,7 +4265,7 @@ static int __do_update_va_mapping(
     rc = mod_l1_entry(pl1e, val, mfn_x(gl1mfn), MMU_NORMAL_PT_UPDATE, v,
                       pg_owner);
 
-    page_unlock(gl1pg);
+    page_unlock(gl1pg, 1);
     put_page(gl1pg);
 
  out:
diff --git a/xen/arch/x86/mm/mem_sharing.c b/xen/arch/x86/mm/mem_sharing.c
index 345a1778f9..777af7f7c7 100644
--- a/xen/arch/x86/mm/mem_sharing.c
+++ b/xen/arch/x86/mm/mem_sharing.c
@@ -118,7 +118,7 @@ static inline int mem_sharing_page_lock(struct page_info *pg)
     pg_lock_data_t *pld = &(this_cpu(__pld));
 
     page_sharing_mm_pre_lock();
-    rc = page_lock(pg);
+    rc = page_lock(pg, 0);
     if ( rc )
     {
         preempt_disable();
@@ -135,7 +135,7 @@ static inline void mem_sharing_page_unlock(struct page_info *pg)
     page_sharing_mm_unlock(pld->mm_unlock_level, 
                            &pld->recurse_count);
     preempt_enable();
-    page_unlock(pg);
+    page_unlock(pg, 0);
 }
 
 static inline shr_handle_t get_next_handle(void)
diff --git a/xen/arch/x86/pv/grant_table.c b/xen/arch/x86/pv/grant_table.c
index 5180334f42..be9bbe7c4c 100644
--- a/xen/arch/x86/pv/grant_table.c
+++ b/xen/arch/x86/pv/grant_table.c
@@ -101,7 +101,7 @@ int create_grant_pv_mapping(uint64_t addr, mfn_t frame,
             goto out_unmap;
     }
 
-    if ( !page_lock(page) )
+    if ( !page_lock(page, 1) )
         goto out_put;
 
     if ( (page->u.inuse.type_info & PGT_type_mask) != PGT_l1_page_table )
@@ -112,7 +112,7 @@ int create_grant_pv_mapping(uint64_t addr, mfn_t frame,
         rc = GNTST_okay;
 
  out_unlock:
-    page_unlock(page);
+    page_unlock(page, 1);
  out_put:
     put_page(page);
  out_unmap:
@@ -158,7 +158,7 @@ static bool steal_linear_address(unsigned long linear, l1_pgentry_t *out)
     if ( !page )
         goto out_unmap;
 
-    if ( !page_lock(page) )
+    if ( !page_lock(page, 1) )
         goto out_put;
 
     if ( (page->u.inuse.type_info & PGT_type_mask) != PGT_l1_page_table )
@@ -171,7 +171,7 @@ static bool steal_linear_address(unsigned long linear, l1_pgentry_t *out)
         *out = ol1e;
 
  out_unlock:
-    page_unlock(page);
+    page_unlock(page, 1);
  out_put:
     put_page(page);
  out_unmap:
@@ -264,7 +264,7 @@ int replace_grant_pv_mapping(uint64_t addr, mfn_t frame,
             goto out_unmap;
     }
 
-    if ( !page_lock(page) )
+    if ( !page_lock(page, 1) )
         goto out_put;
 
     if ( (page->u.inuse.type_info & PGT_type_mask) != PGT_l1_page_table )
@@ -297,7 +297,7 @@ int replace_grant_pv_mapping(uint64_t addr, mfn_t frame,
         rc = GNTST_okay;
 
  out_unlock:
-    page_unlock(page);
+    page_unlock(page, 1);
  out_put:
     put_page(page);
  out_unmap:
diff --git a/xen/arch/x86/pv/ro-page-fault.c b/xen/arch/x86/pv/ro-page-fault.c
index e7a7179dda..8e90e82f0b 100644
--- a/xen/arch/x86/pv/ro-page-fault.c
+++ b/xen/arch/x86/pv/ro-page-fault.c
@@ -277,7 +277,7 @@ static int ptwr_do_page_fault(struct x86_emulate_ctxt *ctxt,
     if ( !page )
         return X86EMUL_UNHANDLEABLE;
 
-    if ( !page_lock(page) )
+    if ( !page_lock(page, 1) )
     {
         put_page(page);
         return X86EMUL_UNHANDLEABLE;
@@ -285,7 +285,7 @@ static int ptwr_do_page_fault(struct x86_emulate_ctxt *ctxt,
 
     if ( (page->u.inuse.type_info & PGT_type_mask) != PGT_l1_page_table )
     {
-        page_unlock(page);
+        page_unlock(page, 1);
         put_page(page);
         return X86EMUL_UNHANDLEABLE;
     }
@@ -293,7 +293,7 @@ static int ptwr_do_page_fault(struct x86_emulate_ctxt *ctxt,
     ctxt->data = &ptwr_ctxt;
     rc = x86_emulate(ctxt, &ptwr_emulate_ops);
 
-    page_unlock(page);
+    page_unlock(page, 1);
     put_page(page);
 
     return rc;
diff --git a/xen/include/asm-x86/mm.h b/xen/include/asm-x86/mm.h
index 6faa563167..dae52e8880 100644
--- a/xen/include/asm-x86/mm.h
+++ b/xen/include/asm-x86/mm.h
@@ -375,8 +375,8 @@ const struct platform_bad_page *get_platform_badpages(unsigned int *array_size);
  * These two users (pte serialization and memory sharing) do not collide, since
  * sharing is only supported for hvm guests, which do not perform pv pte updates.
  */
-int page_lock(struct page_info *page);
-void page_unlock(struct page_info *page);
+int page_lock(struct page_info *page, bool lock_check);
+void page_unlock(struct page_info *page, bool lock_check);
 
 void put_page_type(struct page_info *page);
 int  get_page_type(struct page_info *page, unsigned long type);
