Merge branch 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git...

[platform/kernel/linux-starfive.git] / mm / mremap.c

diff --git a/mm/mremap.c b/mm/mremap.c
index d6959cb..87bb839 100644 (file)
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -221,6 +221,15 @@ static unsigned long move_vma(struct vm_area_struct *vma,
        moved_len = move_page_tables(vma, old_addr, new_vma, new_addr, old_len);
        if (moved_len < old_len) {
                /*
+                * Before moving the page tables from the new vma to
+                * the old vma, we need to be sure the old vma is
+                * queued after new vma in the same_anon_vma list to
+                * prevent SMP races with rmap_walk (that could lead
+                * rmap_walk to miss some page table).
+                */
+               anon_vma_moveto_tail(vma);
+
+               /*
                 * On error, move entries back from new area to old,
                 * which will succeed since page tables still there,
                 * and then proceed to unmap new area instead of old.