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From: David Hildenbrand <david@redhat.com>
To: Alastair D'Silva <alastair@au1.ibm.com>, alastair@d-silva.org
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Oscar Salvador <osalvador@suse.com>,
	Michal Hocko <mhocko@suse.com>,
	Pavel Tatashin <pasha.tatashin@soleen.com>,
	Dan Williams <dan.j.williams@intel.com>,
	Wei Yang <richard.weiyang@gmail.com>, Qian Cai <cai@lca.pw>,
	Jason Gunthorpe <jgg@ziepe.ca>,
	Logan Gunthorpe <logang@deltatee.com>,
	Ira Weiny <ira.weiny@intel.com>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/2] mm: Add a bounds check in devm_memremap_pages()
Date: Tue, 10 Sep 2019 09:38:57 +0200	[thread overview]
Message-ID: <6ca671a0-8b00-e974-7de9-a574ad9b77ec@redhat.com> (raw)
In-Reply-To: <20190910025225.25904-3-alastair@au1.ibm.com>

On 10.09.19 04:52, Alastair D'Silva wrote:
> From: Alastair D'Silva <alastair@d-silva.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@d-silva.org>
> ---
>  mm/memremap.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/mm/memremap.c b/mm/memremap.c
> index 86432650f829..fd00993caa3e 100644
> --- a/mm/memremap.c
> +++ b/mm/memremap.c
> @@ -269,6 +269,13 @@ void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap)
>  
>  	mem_hotplug_begin();
>  
> +	error = check_hotplug_memory_addressable(res->start,
> +						 resource_size(res));
> +	if (error) {
> +		mem_hotplug_done();
> +		goto err_checkrange;
> +	}
> +

No need to check under the memory hotplug lock.

>  	/*
>  	 * For device private memory we call add_pages() as we only need to
>  	 * allocate and initialize struct page for the device memory. More-
> @@ -324,6 +331,7 @@ void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap)
>  
>   err_add_memory:
>  	kasan_remove_zero_shadow(__va(res->start), resource_size(res));
> + err_checkrange:
>   err_kasan:
>  	untrack_pfn(NULL, PHYS_PFN(res->start), resource_size(res));
>   err_pfn_remap:
> 


-- 

Thanks,

David / dhildenb

  reply	other threads:[~2019-09-10  7:39 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-10  2:52 [PATCH 0/2] Add bounds check for Hotplugged memory Alastair D'Silva
2019-09-10  2:52 ` [PATCH 1/2] memory_hotplug: Add a bounds check to check_hotplug_memory_range() Alastair D'Silva
2019-09-10  7:45   ` David Hildenbrand
2019-09-10 10:26     ` Alastair D'Silva
2019-09-10  7:45   ` David Hildenbrand
2019-09-10 10:15   ` Kirill A. Shutemov
2019-09-10 10:28     ` Alastair D'Silva
2019-09-10  2:52 ` [PATCH 2/2] mm: Add a bounds check in devm_memremap_pages() Alastair D'Silva
2019-09-10  7:38   ` David Hildenbrand [this message]
2019-09-10 10:24     ` Alastair D'Silva

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