Write-lock all VMAs which might be affected by a merge, split, expand
or shrink operations. All these operations use vma_prepare() before
making the modifications, therefore it provides a centralized place to
perform VMA locking.
Signed-off-by: Suren Baghdasaryan <surenb@xxxxxxxxxx>
---
mm/mmap.c | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/mm/mmap.c b/mm/mmap.c
index 92893d86c0af..e73fbb84ce12 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -502,6 +502,16 @@ static inline void init_vma_prep(struct vma_prepare *vp,
*/
static inline void vma_prepare(struct vma_prepare *vp)
{
+ if (vp->vma)
+ vma_start_write(vp->vma);
+ if (vp->adj_next)
+ vma_start_write(vp->adj_next);
+ /* vp->insert is always a newly created VMA, no need for locking */
+ if (vp->remove)
+ vma_start_write(vp->remove);
+ if (vp->remove2)
+ vma_start_write(vp->remove2);
+
if (vp->file) {
uprobe_munmap(vp->vma, vp->vma->vm_start, vp->vma->vm_end);
--
2.39.2.722.g9855ee24e9-goog
