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-rw-r--r--mm/mmap.c12
1 files changed, 12 insertions, 0 deletions
diff --git a/mm/mmap.c b/mm/mmap.c
index 886de799e7d2..10598e5d4757 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -3422,6 +3422,17 @@ static int special_mapping_mremap(struct vm_area_struct *new_vma,
return 0;
}
+static int special_mapping_split(struct vm_area_struct *vma, unsigned long addr)
+{
+ /*
+ * Forbid splitting special mappings - kernel has expectations over
+ * the number of pages in mapping. Together with VM_DONTEXPAND
+ * the size of vma should stay the same over the special mapping's
+ * lifetime.
+ */
+ return -EINVAL;
+}
+
static const struct vm_operations_struct special_mapping_vmops = {
.close = special_mapping_close,
.fault = special_mapping_fault,
@@ -3429,6 +3440,7 @@ static const struct vm_operations_struct special_mapping_vmops = {
.name = special_mapping_name,
/* vDSO code relies that VVAR can't be accessed remotely */
.access = NULL,
+ .may_split = special_mapping_split,
};
static const struct vm_operations_struct legacy_special_mapping_vmops = {

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