2022-09-01 17:47:48

by Suren Baghdasaryan

Subject: [RFC PATCH RESEND 12/28] mm/mremap: mark VMA as locked while remapping it to a new address range

Mark VMA as locked before copying it and when copy_vma produces a new VMA.

Signed-off-by: Suren Baghdasaryan <[email protected]>
---
mm/mmap.c | 1 +
mm/mremap.c | 1 +
2 files changed, 2 insertions(+)

diff --git a/mm/mmap.c b/mm/mmap.c
index ade3909c89b4..121544fd90de 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -3248,6 +3248,7 @@ struct vm_area_struct *copy_vma(struct vm_area_struct **vmap,
get_file(new_vma->vm_file);
if (new_vma->vm_ops && new_vma->vm_ops->open)
new_vma->vm_ops->open(new_vma);
+ vma_mark_locked(new_vma);
vma_link(mm, new_vma, prev, rb_link, rb_parent);
*need_rmap_locks = false;
}
diff --git a/mm/mremap.c b/mm/mremap.c
index b522cd0259a0..bdbf96254e43 100644
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -620,6 +620,7 @@ static unsigned long move_vma(struct vm_area_struct *vma,
return -ENOMEM;
}

+ vma_mark_locked(vma);
new_pgoff = vma->vm_pgoff + ((old_addr - vma->vm_start) >> PAGE_SHIFT);
new_vma = copy_vma(&vma, new_addr, new_len, new_pgoff,
&need_rmap_locks);
--
2.37.2.789.g6183377224-goog

2022-09-06 17:00:16

by Laurent Dufour

Subject: Re: [RFC PATCH RESEND 12/28] mm/mremap: mark VMA as locked while remapping it to a new address range

Le 01/09/2022 à 19:35, Suren Baghdasaryan a écrit :
> Mark VMA as locked before copying it and when copy_vma produces a new VMA.
>
> Signed-off-by: Suren Baghdasaryan <[email protected]>
> ---
> mm/mmap.c | 1 +
> mm/mremap.c | 1 +
> 2 files changed, 2 insertions(+)
>
> diff --git a/mm/mmap.c b/mm/mmap.c
> index ade3909c89b4..121544fd90de 100644
> --- a/mm/mmap.c
> +++ b/mm/mmap.c
> @@ -3248,6 +3248,7 @@ struct vm_area_struct *copy_vma(struct vm_area_struct **vmap,
> get_file(new_vma->vm_file);
> if (new_vma->vm_ops && new_vma->vm_ops->open)
> new_vma->vm_ops->open(new_vma);
> + vma_mark_locked(new_vma);
> vma_link(mm, new_vma, prev, rb_link, rb_parent);
> *need_rmap_locks = false;
> }

Sounds good in the both case the returned new_vma is locked, either in
copy_vma() or in vma_merge().

> diff --git a/mm/mremap.c b/mm/mremap.c
> index b522cd0259a0..bdbf96254e43 100644
> --- a/mm/mremap.c
> +++ b/mm/mremap.c
> @@ -620,6 +620,7 @@ static unsigned long move_vma(struct vm_area_struct *vma,
> return -ENOMEM;
> }
>
> + vma_mark_locked(vma);
> new_pgoff = vma->vm_pgoff + ((old_addr - vma->vm_start) >> PAGE_SHIFT);
> new_vma = copy_vma(&vma, new_addr, new_len, new_pgoff,
> &need_rmap_locks);

Reviewed-by: Laurent Dufour <[email protected]>