linux-kernel - Re: [RFC PATCH v2 2/2] Architecture defined limit on memory region random shift.

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

Message-Id: <548B6BB8-FD6F-4F8D-B67F-2809305C617D@gmail.com>
Date:   Fri, 23 Mar 2018 20:49:03 +0300
From:   Ilya Smith <blackzert@...il.com>
To:     Andrew Morton <akpm@...ux-foundation.org>
Cc:     rth@...ddle.net, ink@...assic.park.msu.ru, mattst88@...il.com,
        vgupta@...opsys.com, linux@...linux.org.uk, tony.luck@...el.com,
        fenghua.yu@...el.com, jhogan@...nel.org, ralf@...ux-mips.org,
        jejb@...isc-linux.org, deller@....de, benh@...nel.crashing.org,
        paulus@...ba.org, mpe@...erman.id.au, schwidefsky@...ibm.com,
        heiko.carstens@...ibm.com, ysato@...rs.sourceforge.jp,
        dalias@...c.org, davem@...emloft.net, tglx@...utronix.de,
        mingo@...hat.com, hpa@...or.com, x86@...nel.org,
        nyc@...omorphy.com, viro@...iv.linux.org.uk, arnd@...db.de,
        gregkh@...uxfoundation.org, deepa.kernel@...il.com,
        mhocko@...e.com, hughd@...gle.com, kstewart@...uxfoundation.org,
        pombredanne@...b.com, steve.capper@....com, punit.agrawal@....com,
        paul.burton@...s.com, aneesh.kumar@...ux.vnet.ibm.com,
        npiggin@...il.com, keescook@...omium.org, bhsharma@...hat.com,
        riel@...hat.com, nitin.m.gupta@...cle.com,
        kirill.shutemov@...ux.intel.com, dan.j.williams@...el.com,
        jack@...e.cz, ross.zwisler@...ux.intel.com, jglisse@...hat.com,
        willy@...radead.org, aarcange@...hat.com, oleg@...hat.com,
        linux-alpha@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-snps-arc@...ts.infradead.org,
        linux-arm-kernel@...ts.infradead.org, linux-ia64@...r.kernel.org,
        linux-metag@...r.kernel.org, linux-mips@...ux-mips.org,
        linux-parisc@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org,
        linux-s390@...r.kernel.org, linux-sh@...r.kernel.org,
        sparclinux@...r.kernel.org, linux-mm@...ck.org
Subject: Re: [RFC PATCH v2 2/2] Architecture defined limit on memory region
 random shift.


> On 22 Mar 2018, at 23:54, Andrew Morton <akpm@...ux-foundation.org> wrote:
> 
> 
> Please add changelogs.  An explanation of what a "limit on memory
> region random shift" is would be nice ;) Why does it exist, why are we
> doing this, etc.  Surely there's something to be said - at present this
> is just a lump of random code?
> 
> 
> 
Sorry, my bad. The main idea of this limit is to decrease possible memory 
fragmentation. This is not so big problem on 64bit process, but really big for 
32 bit processes since may cause failure memory allocation. To control memory 
fragmentation and protect 32 bit systems (or architectures) this limit was 
introduce by this patch. It could be also moved to CONFIG_ as well.