[PATCH 22/41] mm/mremap: write-lock VMA while remapping it to a new address range

[Suren Baghdasaryan]

Write-lock VMA as locked before copying it and when copy_vma produces
a new VMA.

Signed-off-by: Suren Baghdasaryan <sur...@google.com>
Reviewed-by: Laurent Dufour <laurent.duf...@fr.ibm.com>
---
 mm/mmap.c   | 1 +
 mm/mremap.c | 1 +
 2 files changed, 2 insertions(+)

diff --git a/mm/mmap.c b/mm/mmap.c
index ff02cb51e7e7..da1908730828 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -3261,6 +3261,7 @@ struct vm_area_struct *copy_vma(struct vm_area_struct 
**vmap,
                        get_file(new_vma->vm_file);
                if (new_vma->vm_ops && new_vma->vm_ops->open)
                        new_vma->vm_ops->open(new_vma);
+               vma_write_lock(new_vma);
                if (vma_link(mm, new_vma))
                        goto out_vma_link;
                *need_rmap_locks = false;
diff --git a/mm/mremap.c b/mm/mremap.c
index 2ccdd1561f5b..d24a79bcb1a1 100644
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -622,6 +622,7 @@ static unsigned long move_vma(struct vm_area_struct *vma,
                        return -ENOMEM;
        }
 
+       vma_write_lock(vma);
        new_pgoff = vma->vm_pgoff + ((old_addr - vma->vm_start) >> PAGE_SHIFT);
        new_vma = copy_vma(&vma, new_addr, new_len, new_pgoff,
                           &need_rmap_locks);
-- 
2.39.0