linux-kernel - Re: [PATCH v13 3/3] mm, powerpc, x86: introduce an additional vma bit for powerpc pkey

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:   Fri, 4 May 2018 21:42:39 -0700
From:   Dave Hansen <dave.hansen@...el.com>
To:     Ram Pai <linuxram@...ibm.com>
Cc:     mpe@...erman.id.au, mingo@...hat.com, akpm@...ux-foundation.org,
        linuxppc-dev@...ts.ozlabs.org, linux-mm@...ck.org, x86@...nel.org,
        linux-arch@...r.kernel.org, linux-kernel@...r.kernel.org,
        benh@...nel.crashing.org, paulus@...ba.org,
        khandual@...ux.vnet.ibm.com, aneesh.kumar@...ux.vnet.ibm.com,
        bsingharora@...il.com, hbabu@...ibm.com, mhocko@...nel.org,
        bauerman@...ux.vnet.ibm.com, ebiederm@...ssion.com, corbet@....net,
        arnd@...db.de
Subject: Re: [PATCH v13 3/3] mm, powerpc, x86: introduce an additional vma bit
 for powerpc pkey

On 05/04/2018 06:12 PM, Ram Pai wrote:
>> That new line boils down to:
>>
>> 		[ilog2(0)]	= "",
>>
>> on x86.  It wasn't *obvious* to me that it is OK to do that.  The other
>> possibly undefined bits (VM_SOFTDIRTY for instance) #ifdef themselves
>> out of this array.
>>
>> I would just be a wee bit worried that this would overwrite the 0 entry
>> ("??") with "".
> Yes it would :-( and could potentially break anything that depends on
> 0th entry being "??"
> 
> Is the following fix acceptable?
> 
> #if VM_PKEY_BIT4
>                 [ilog2(VM_PKEY_BIT4)]   = "",
> #endif

Yep, I think that works for me.