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Since you've not sent the PR to Linus yet maybe you could squash this > > in? Otherwise obviously one for 6.15-rc1. > > > > I've tested against the repro and confirm it fixes it, also the fix is > > 'obvious' as is the cause. I have replied to [0] with an explanation there > > also inline. > > > > Apologies for missing this before! > > > > Thanks, Lorenzo > > > > [0]: https://lore.kernel.org/linux-mm/Z+lcvEIHMLiKVR1i@ly-workstation/ > > > > ----8<---- > > From 3709f42feb30e2cfe2f39527d4cd8c74a9e8b724 Mon Sep 17 00:00:00 2001 > > From: Lorenzo Stoakes > > Date: Sun, 30 Mar 2025 17:20:48 +0100 > > Subject: [PATCH] mm/mremap: do not set vrm->vma NULL immediately prior to > > checking it > > > > This seems rather unwise. If we cannot merge, extend, then we need to > > recall the original VMA to see if we need to uncharge. > > > > If we do need to, do so. > > > > Signed-off-by: Lorenzo Stoakes > > Acked-by: Vlastimil Babka > > Can we get a testcase that hits this path? :) Ack, will add! > > > > > --- > > mm/mremap.c | 3 ++- > > 1 file changed, 2 insertions(+), 1 deletion(-) > > > > diff --git a/mm/mremap.c b/mm/mremap.c > > index 0865387531ed..7db9da609c84 100644 > > --- a/mm/mremap.c > > +++ b/mm/mremap.c > > @@ -1561,11 +1561,12 @@ static unsigned long expand_vma_in_place(struct vma_remap_struct *vrm) > > * adjacent to the expanded vma and otherwise > > * compatible. > > */ > > - vma = vrm->vma = vma_merge_extend(&vmi, vma, vrm->delta); > > + vma = vma_merge_extend(&vmi, vma, vrm->delta); > > if (!vma) { > > vrm_uncharge(vrm); > > return -ENOMEM; > > } > > + vrm->vma = vma; > > > > vrm_stat_account(vrm, vrm->delta); > > > > -- > > 2.49.0 >