On Sat, 22 Feb 2025 16:19:52 +0000 Lorenzo Stoakes lorenzo.stoakes@oracle.com 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); _