1 files changed, 5 insertions, 2 deletions

diff --git a/mm/mmap.c b/mm/mmap.c
index cfc0cdca421e..918c9ec5043f 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -390,8 +390,9 @@ static long vma_compute_subtree_gap(struct vm_area_struct *vma)
 }
 
 #ifdef CONFIG_DEBUG_VM_RB
-static int browse_rb(struct rb_root *root)
+static int browse_rb(struct mm_struct *mm)
 {
+        struct rb_root *root = &mm->mm_rb;
         int i = 0, j, bug = 0;
         struct rb_node *nd, *pn = NULL;
         unsigned long prev = 0, pend = 0;
@@ -414,12 +415,14 @@ static int browse_rb(struct rb_root *root)
                                   vma->vm_start, vma->vm_end);
                         bug = 1;
                 }
+                spin_lock(&mm->page_table_lock);
                 if (vma->rb_subtree_gap != vma_compute_subtree_gap(vma)) {
                         pr_emerg("free gap %lx, correct %lx\n",
                                vma->rb_subtree_gap,
                                vma_compute_subtree_gap(vma));
                         bug = 1;
                 }
+                spin_unlock(&mm->page_table_lock);
                 i++;
                 pn = nd;
                 prev = vma->vm_start;
@@ -475,7 +478,7 @@ static void validate_mm(struct mm_struct *mm)
                           mm->highest_vm_end, highest_address);
                 bug = 1;
         }
-        i = browse_rb(&mm->mm_rb);
+        i = browse_rb(mm);
         if (i != mm->map_count) {
                 if (i != -1)
                         pr_emerg("map_count %d rb %d\n", mm->map_count, i);