linux-kernel - Re: [PATCH] mm: add VM_STATIC flag to vmalloc and prevent from removing the areas

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: <20170412173151.GA23054@infradead.org>
Date:   Wed, 12 Apr 2017 10:31:51 -0700
From:   Christoph Hellwig <hch@...radead.org>
To:     Hoeun Ryu <hoeun.ryu@...il.com>
Cc:     Christoph Hellwig <hch@...radead.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Andrey Ryabinin <aryabinin@...tuozzo.com>,
        Andreas Dilger <adilger@...ger.ca>,
        Vlastimil Babka <vbabka@...e.cz>,
        Michal Hocko <mhocko@...e.com>,
        Chris Wilson <chris@...is-wilson.co.uk>,
        Ingo Molnar <mingo@...nel.org>, zijun_hu <zijun_hu@....com>,
        Matthew Wilcox <mawilcox@...rosoft.com>,
        Thomas Garnier <thgarnie@...gle.com>,
        "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
        linux-arch@...r.kernel.org, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] mm: add VM_STATIC flag to vmalloc and prevent from
 removing the areas

On Wed, Apr 12, 2017 at 08:42:08PM +0900, Hoeun Ryu wrote:
> 
> > On Apr 12, 2017, at 3:02 PM, Christoph Hellwig <hch@...radead.org> wrote:
> > 
> >> On Wed, Apr 12, 2017 at 02:01:59PM +0900, Hoeun Ryu wrote:
> >> vm_area_add_early/vm_area_register_early() are used to reserve vmalloc area
> >> during boot process and those virtually mapped areas are never unmapped.
> >> So `OR` VM_STATIC flag to the areas in vmalloc_init() when importing
> >> existing vmlist entries and prevent those areas from being removed from the
> >> rbtree by accident.
> > 
> > How would they be removed "by accident"?
> 
> I don't mean actual use-cases, but I just want to make it robust against like programming errors.

Oh, ok.  The patch makes sense then, although the changelog could use
a little update.