Re: [PATCH v3 2/2] mm: Add a bounds check in devm_memremap_pages()

[David Hildenbrand]

On 17.09.19 03:07, Alastair D'Silva wrote:
> From: Alastair D'Silva <alastair@xxxxxxxxxxx>
> 
> The call to check_hotplug_memory_addressable() validates that the memory
> is fully addressable.
> 
> Without this call, it is possible that we may remap pages that is
> not physically addressable, resulting in bogus section numbers
> being returned from __section_nr().
> 
> Signed-off-by: Alastair D'Silva <alastair@xxxxxxxxxxx>
> ---
>  mm/memremap.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/mm/memremap.c b/mm/memremap.c
> index 86432650f829..de2b67586401 100644
> --- a/mm/memremap.c
> +++ b/mm/memremap.c
> @@ -175,6 +175,11 @@ void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap)
>  	int error, nid, is_ram;
>  	bool need_devmap_managed = true;
>  
> +	error = check_hotplug_memory_addressable(res->start,
> +						 resource_size(res));
> +	if (error)
> +		return ERR_PTR(error);
> +
>  	switch (pgmap->type) {
>  	case MEMORY_DEVICE_PRIVATE:
>  		if (!IS_ENABLED(CONFIG_DEVICE_PRIVATE)) {
> 

Acked-by: David Hildenbrand <david@xxxxxxxxxx>

-- 

Thanks,

David / dhildenb