linux-kernel - Re: [RFC 2/4] Deactivate mmap

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]

Message-Id: <e6397c6c-6718-a0f3-0d72-7ad85760fdea@linux.vnet.ibm.com>
Date:   Wed, 19 Apr 2017 15:45:50 +0200
From:   Laurent Dufour <ldufour@...ux.vnet.ibm.com>
To:     Peter Zijlstra <peterz@...radead.org>
Cc:     linux-mm@...ck.org, Davidlohr Bueso <dave@...olabs.net>,
        akpm@...ux-foundation.org, Jan Kara <jack@...e.cz>,
        "Kirill A . Shutemov" <kirill@...temov.name>,
        Michal Hocko <mhocko@...nel.org>,
        Mel Gorman <mgorman@...hsingularity.net>,
        haren@...ux.vnet.ibm.com, aneesh.kumar@...ux.vnet.ibm.com,
        khandual@...ux.vnet.ibm.com, Paul.McKenney@...ibm.com,
        linux-kernel@...r.kernel.org
Subject: Re: [RFC 2/4] Deactivate mmap_sem assert

On 19/04/2017 14:30, Peter Zijlstra wrote:
> On Wed, Apr 19, 2017 at 02:18:25PM +0200, Laurent Dufour wrote:
>> When mmap_sem will be moved to a range lock, some assertion done in
>> the code are no more valid, like the one ensuring mmap_sem is held.
>>
> 
> Why are they no longer valid?

I didn't explain that very well..

When using a range lock we can't check that the lock is simply held, but
if the range we are interesting on is locked or not.

As I mentioned this patch will have to be reverted / reviewed once the
range lock is providing dedicated APIs, but some check might be
difficult to adapt to a range.