Re: [PATCH v4 21/21] mm: on remap assert that input range within the proposed VMA

On 3/20/26 23:39, Lorenzo Stoakes (Oracle) wrote:
> Now we have range_in_vma_desc(), update remap_pfn_range_prepare() to check
> whether the input range in contained within the specified VMA, so we can
> fail at prepare time if an invalid range is specified.
> 
> This covers the I/O remap mmap actions also which ultimately call into
> this function, and other mmap action types either already span the full
> VMA or check this already.
> 
> Reviewed-by: Suren Baghdasaryan <[email protected]>
> Signed-off-by: Lorenzo Stoakes (Oracle) <[email protected]>

Acked-by: Vlastimil Babka (SUSE) <[email protected]>

> ---
>  mm/memory.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/mm/memory.c b/mm/memory.c
> index 53ef8ef3d04a..68cc592ff0ba 100644
> --- a/mm/memory.c
> +++ b/mm/memory.c
> @@ -3142,6 +3142,9 @@ int remap_pfn_range_prepare(struct vm_area_desc *desc)
>  	const bool is_cow = vma_desc_is_cow_mapping(desc);
>  	int err;
>  
> +	if (!range_in_vma_desc(desc, start, end))
> +		return -EFAULT;
> +
>  	err = get_remap_pgoff(is_cow, start, end, desc->start, desc->end, pfn,
>  			      &desc->pgoff);
>  	if (err)