linux-kernel - Re: [RFC] mm: Change the data type of huge page size from unsigned long to u64

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 for Android: free password hash cracker in your pocket

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

Message-Id: <cc71f567-918d-ea01-e262-0a4458b5cfee@linux.vnet.ibm.com>
Date:   Tue, 13 Sep 2016 21:08:33 +0800
From:   Rui Teng <rui.teng@...ux.vnet.ibm.com>
To:     "Kirill A. Shutemov" <kirill@...temov.name>
Cc:     linux-kernel@...r.kernel.org, linux-mm@...ck.org,
        Andrew Morton <akpm@...ux-foundation.org>,
        Michal Hocko <mhocko@...e.com>,
        Naoya Horiguchi <n-horiguchi@...jp.nec.com>,
        Chen Gang <chengang@...ndsoft.com.cn>,
        "Kirill A . Shutemov" <kirill.shutemov@...ux.intel.com>,
        Vlastimil Babka <vbabka@...e.cz>,
        "Aneesh Kumar K . V" <aneesh.kumar@...ux.vnet.ibm.com>,
        hejianet@...ux.vnet.ibm.com
Subject: Re: [RFC] mm: Change the data type of huge page size from unsigned
 long to u64

On 9/13/16 7:40 PM, Kirill A. Shutemov wrote:
> On Tue, Sep 13, 2016 at 07:21:07PM +0800, Rui Teng wrote:
>> On 9/13/16 5:32 PM, Kirill A. Shutemov wrote:
>>> On Tue, Sep 13, 2016 at 05:26:05PM +0800, Rui Teng wrote:
>>>> The huge page size could be 16G(0x400000000) on ppc64 architecture, and it will
>>>> cause an overflow on unsigned long data type(0xFFFFFFFF).
>>>
>>> Huh? ppc64 is 64-bit system and sizeof(void *) is equal to
>>> sizeof(unsigned long) on Linux (LP64 model).
>>>
>>> So where your 0xFFFFFFFF comes from?
>>>
>> The size of unsigned long data type is 4 bytes
>
> No, it's not.
>
Sorry, my fault!
I print the unsigned long with "%ul" instead of "%lu" and got the wrong
result. Sorry!