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-rw-r--r--mm/madvise.c8
1 files changed, 7 insertions, 1 deletions
diff --git a/mm/madvise.c b/mm/madvise.c
index 1f2693dccf7b..38d0f515d548 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -131,6 +131,8 @@ static int replace_anon_vma_name(struct vm_area_struct *vma,
/*
* Update the vm_flags on region of a vma, splitting it or merging it as
* necessary. Must be called with mmap_sem held for writing;
+ * Caller should ensure anon_name stability by raising its refcount even when
+ * anon_name belongs to a valid vma because this function might free that vma.
*/
static int madvise_update_vma(struct vm_area_struct *vma,
struct vm_area_struct **prev, unsigned long start,
@@ -945,6 +947,7 @@ static int madvise_vma_behavior(struct vm_area_struct *vma,
unsigned long behavior)
{
int error;
+ struct anon_vma_name *anon_name;
unsigned long new_flags = vma->vm_flags;
switch (behavior) {
@@ -1010,8 +1013,11 @@ static int madvise_vma_behavior(struct vm_area_struct *vma,
break;
}
+ anon_name = anon_vma_name(vma);
+ anon_vma_name_get(anon_name);
error = madvise_update_vma(vma, prev, start, end, new_flags,
- anon_vma_name(vma));
+ anon_name);
+ anon_vma_name_put(anon_name);
out:
/*