linux-kernel - Re: [PATCH v3 2/2] mm: Add a bounds check in devm_memremap

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Message-ID: <9208cdeb-6f14-6237-c919-a2d31e8d506a@redhat.com>
Date:   Tue, 17 Sep 2019 09:27:26 +0200
From:   David Hildenbrand <david@...hat.com>
To:     Alastair D'Silva <alastair@....ibm.com>, alastair@...ilva.org
Cc:     Andrew Morton <akpm@...ux-foundation.org>,
        Oscar Salvador <osalvador@...e.com>,
        Michal Hocko <mhocko@...e.com>,
        Pavel Tatashin <pasha.tatashin@...een.com>,
        Wei Yang <richard.weiyang@...il.com>,
        Dan Williams <dan.j.williams@...el.com>, Qian Cai <cai@....pw>,
        Jason Gunthorpe <jgg@...pe.ca>,
        Logan Gunthorpe <logang@...tatee.com>,
        Ira Weiny <ira.weiny@...el.com>, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 2/2] mm: Add a bounds check in devm_memremap_pages()

On 17.09.19 03:07, Alastair D'Silva wrote:
> From: Alastair D'Silva <alastair@...ilva.org>
> 
> 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@...ilva.org>
> ---
>  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@...hat.com>

-- 

Thanks,

David / dhildenb