[PATCH v6 04/16] mm/nommu: fix the last places where vma is not locked before being attached

Suren Baghdasaryan
2024-12-16T19:24:36Z

nommu configuration has two places where vma gets attached to the vma tree
without write-locking it. Add the missing locks to ensure vma is always
locked before it's attached.

Signed-off-by: Suren Baghdasaryan <surenb@google.com>
---
mm/nommu.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/mm/nommu.c b/mm/nommu.c
index 9cb6e99215e2..248392ef4048 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -1189,6 +1189,7 @@ unsigned long do_mmap(struct file *file,
goto error_just_free;

setup_vma_to_mm(vma, current->mm);
+ vma_start_write(vma);
current->mm->map_count++;
/* add the VMA to the tree */
vma_iter_store(&vmi, vma);
@@ -1356,6 +1357,7 @@ static int split_vma(struct vma_iterator *vmi, struct vm_area_struct *vma,

setup_vma_to_mm(vma, mm);
setup_vma_to_mm(new, mm);
+ vma_start_write(new);
vma_iter_store(vmi, new);
mm->map_count++;
return 0;
--
2.47.1.613.gc27f4b7a9f-goog