linux-kernel - Re: [PATCH 4/5] mm: gup: fix potential pgmap refcnt leak in __gup_device

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Sun, 8 Aug 2021 14:16:53 -0700
From:   John Hubbard <jhubbard@...dia.com>
To:     Andrew Morton <akpm@...ux-foundation.org>,
        Miaohe Lin <linmiaohe@...wei.com>, <imbrenda@...ux.ibm.com>,
        <kirill.shutemov@...ux.intel.com>, <jack@...e.cz>,
        <linux-mm@...ck.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 4/5] mm: gup: fix potential pgmap refcnt leak in
 __gup_device_huge()

On 8/7/21 11:45 AM, Andrew Morton wrote:
> On Sat, 7 Aug 2021 11:41:12 -0700 Andrew Morton <akpm@...ux-foundation.org> wrote:
> 
>> We can simplify further, and remove the troublesome multiple return points?
>>
> 
> oops.

I sent a reviewed by to the "+" fixup email, but just realized that that did not
hit the main
  mailing list. So:



For the end result of these stacked fixes to this file:



Reviewed-by: John Hubbard <jhubbard@...dia.com>



thanks,

-- 

John Hubbard

NVIDIA
> 
> --- a/mm/gup.c~mm-gup-fix-potential-pgmap-refcnt-leak-in-__gup_device_huge-fix-fix
> +++ a/mm/gup.c
> @@ -2240,6 +2240,7 @@ static int __gup_device_huge(unsigned lo
>   {
>   	int nr_start = *nr;
>   	struct dev_pagemap *pgmap = NULL;
> +	int ret = 1;
>   
>   	do {
>   		struct page *page = pfn_to_page(pfn);
> @@ -2247,12 +2248,14 @@ static int __gup_device_huge(unsigned lo
>   		pgmap = get_dev_pagemap(pfn, pgmap);
>   		if (unlikely(!pgmap)) {
>   			undo_dev_pagemap(nr, nr_start, flags, pages);
> +			ret = 0;
>   			break;
>   		}
>   		SetPageReferenced(page);
>   		pages[*nr] = page;
>   		if (unlikely(!try_grab_page(page, flags))) {
>   			undo_dev_pagemap(nr, nr_start, flags, pages);
> +			ret = 0;
>   			break;
>   		}
>   		(*nr)++;
> @@ -2260,7 +2263,7 @@ static int __gup_device_huge(unsigned lo
>   	} while (addr += PAGE_SIZE, addr != end);
>   
>   	put_dev_pagemap(pgmap);
> -	return 1;
> +	return ret;
>   }
>   
>   static int __gup_device_huge_pmd(pmd_t orig, pmd_t *pmdp, unsigned long addr,
> 
> Not sure if it's worth bothering, really...
>