From: Ingo Molnar <mingo@kernel•org>
To: Timothy Pepper <timothy.c.pepper@linux•intel.com>
Cc: linux-mips@linux-mips•org, linux-sh@vger•kernel.org,
linux-mm@kvack•org, Paul Mackerras <paulus@samba•org>,
"H. Peter Anvin" <hpa@zytor•com>,
sparclinux@vger•kernel.org, Michel Lespinasse <walken@google•com>,
Russell King <linux@arm•linux.org.uk>,
x86@kernel•org, Ingo Molnar <mingo@redhat•com>,
Rik van Riel <riel@redhat•com>, Al Viro <viro@zeniv•linux.org.uk>,
James Morris <james.l.morris@oracle•com>,
Thomas Gleixner <tglx@linutronix•de>,
linux-arm-kernel@lists•infradead.org,
linuxppc-dev@lists•ozlabs.org, Ralf Baechle <ralf@linux-mips•org>,
Paul Mundt <lethal@linux-sh•org>,
Andrew Morton <akpm@linux-foundation•org>,
Linus Torvalds <torvalds@linux-foundation•org>,
"David S. Miller" <davem@davemloft•net>
Subject: Re: mm: insure topdown mmap chooses addresses above security minimum
Date: Wed, 25 Sep 2013 19:44:36 +0200 [thread overview]
Message-ID: <20130925174436.GA14037@gmail.com> (raw)
In-Reply-To: <20130925171243.GA7428@tcpepper-desk.jf.intel.com>
* Timothy Pepper <timothy.c.pepper@linux•intel.com> wrote:
> On Wed 25 Sep at 09:30:49 +0200 mingo@kernel•org said:
> > > info.flags = VM_UNMAPPED_AREA_TOPDOWN;
> > > info.length = len;
> > > - info.low_limit = PAGE_SIZE;
> > > + info.low_limit = max(PAGE_SIZE, PAGE_ALIGN(mmap_min_addr));
> > > info.high_limit = mm->mmap_base;
> > > info.align_mask = filp ? get_align_mask() : 0;
> > > info.align_offset = pgoff << PAGE_SHIFT;
> >
> > There appears to be a lot of repetition in these methods - instead of
> > changing 6 places it would be more future-proof to first factor out the
> > common bits and then to apply the fix to the shared implementation.
>
> Besides that existing redundancy in the multiple somewhat similar
> arch_get_unmapped_area_topdown() functions, I was expecting people might
> question the added redundancy of the six instances of:
>
> max(PAGE_SIZE, PAGE_ALIGN(mmap_min_addr));
That redundancy would be automatically addressed by my suggestion.
Thanks,
Ingo
next prev parent reply other threads:[~2013-09-25 17:44 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-24 21:23 mm: insure topdown mmap chooses addresses above security minimum Timothy Pepper
2013-09-24 21:28 ` Russell King - ARM Linux
2013-09-25 7:30 ` Ingo Molnar
2013-09-25 17:12 ` Timothy Pepper
2013-09-25 17:44 ` Ingo Molnar [this message]
2013-09-27 15:39 ` Timothy Pepper
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