On Sat, 22 Feb 2025 16:19:52 +0000 Lorenzo Stoakes <lorenzo.stoakes@xxxxxxxxxx> wrote:
> The remainder of vma_modify() relies upon the vmg state remaining pristine
> after a merge attempt.
>
This patch is against your "mm: simplify vma merge structure and expand
comments", presently in mm-unstable. I tweaked things (simple) so it
applies to mainline:
--- a/mm/vma.c~mm-abort-vma_modify-on-merge-out-of-memory-failure
+++ a/mm/vma.c
@@ -1509,24 +1509,28 @@ int do_vmi_munmap(struct vma_iterator *v
static struct vm_area_struct *vma_modify(struct vma_merge_struct *vmg)
{
struct vm_area_struct *vma = vmg->vma;
+ unsigned long start = vmg->start;
+ unsigned long end = vmg->end;
struct vm_area_struct *merged;
/* First, try to merge. */
merged = vma_merge_existing_range(vmg);
if (merged)
return merged;
+ if (vmg_nomem(vmg))
+ return ERR_PTR(-ENOMEM);
/* Split any preceding portion of the VMA. */
- if (vma->vm_start < vmg->start) {
- int err = split_vma(vmg->vmi, vma, vmg->start, 1);
+ if (vma->vm_start < start) {
+ int err = split_vma(vmg->vmi, vma, start, 1);
if (err)
return ERR_PTR(err);
}
/* Split any trailing portion of the VMA. */
- if (vma->vm_end > vmg->end) {
- int err = split_vma(vmg->vmi, vma, vmg->end, 0);
+ if (vma->vm_end > end) {
+ int err = split_vma(vmg->vmi, vma, end, 0);
if (err)
return ERR_PTR(err);
_
