Re: [PATCH mm-hotfixes] mm/mseal: update VMA end correctly on merge

[Andrew Morton]

On Fri, 27 Mar 2026 09:06:40 +0000 "Lorenzo Stoakes (Oracle)" <ljs@xxxxxxxxxx> wrote:

> --- a/mm/mseal.c
> +++ b/mm/mseal.c
> @@ -66,7 +66,7 @@ static int mseal_apply(struct mm_struct *mm,
>  		prev = vma;
> 
>  	for_each_vma_range(vmi, vma, end) {
> -		const unsigned long curr_end = MIN(vma->vm_end, end);
> +		unsigned long curr_end = MIN(vma->vm_end, end);
> 
>  		if (!(vma->vm_flags & VM_SEALED)) {
>  			vm_flags_t vm_flags = vma->vm_flags | VM_SEALED;
> @@ -76,6 +76,7 @@ static int mseal_apply(struct mm_struct *mm,
>  			if (IS_ERR(vma))
>  				return PTR_ERR(vma);
>  			vm_flags_set(vma, VM_SEALED);
> +			curr_end = vma->vm_end; /* Merge may have updated. */
>  		}
> 
>  		prev = vma;

This led to some rework in your "mm/vma: convert
vma_modify_flags[_uffd]() to use vma_flags_t".  Please check my
handiwork.

reject:

--- mm/mseal.c~mm-vma-convert-vma_modify_flags-to-use-vma_flags_t
+++ mm/mseal.c
@@ -68,14 +68,17 @@ static int mseal_apply(struct mm_struct
 	for_each_vma_range(vmi, vma, end) {
 		const unsigned long curr_end = MIN(vma->vm_end, end);
 
-		if (!(vma->vm_flags & VM_SEALED)) {
-			vm_flags_t vm_flags = vma->vm_flags | VM_SEALED;
+		if (!vma_test(vma, VMA_SEALED_BIT)) {
+			vma_flags_t vma_flags = vma->flags;
+
+			vma_flags_set(&vma_flags, VMA_SEALED_BIT);
 
 			vma = vma_modify_flags(&vmi, prev, vma, curr_start,
-					       curr_end, &vm_flags);
+					       curr_end, &vma_flags);
 			if (IS_ERR(vma))
 				return PTR_ERR(vma);
-			vm_flags_set(vma, VM_SEALED);
+			vma_start_write(vma);
+			vma_set_flags(vma, VMA_SEALED_BIT);
 		}
 
 		prev = vma;

resolution:

static int mseal_apply(struct mm_struct *mm,
		unsigned long start, unsigned long end)
{
	struct vm_area_struct *vma, *prev;
	unsigned long curr_start = start;
	VMA_ITERATOR(vmi, mm, start);

	/* We know there are no gaps so this will be non-NULL. */
	vma = vma_iter_load(&vmi);
	prev = vma_prev(&vmi);
	if (start > vma->vm_start)
		prev = vma;

	for_each_vma_range(vmi, vma, end) {
		unsigned long curr_end = MIN(vma->vm_end, end);

		if (!vma_test(vma, VMA_SEALED_BIT)) {
			vma_flags_t vma_flags = vma->flags;

			vma_flags_set(&vma_flags, VMA_SEALED_BIT);

			vma = vma_modify_flags(&vmi, prev, vma, curr_start,
					       curr_end, &vma_flags);
			if (IS_ERR(vma))
				return PTR_ERR(vma);
			vma_start_write(vma);
			vma_set_flags(vma, VMA_SEALED_BIT);
			curr_end = vma->vm_end; /* Merge may have updated. */
		}

		prev = vma;
		curr_start = curr_end;
	}

	return 0;
}