From: Kees Cook <kees@outflux.net>
To: "H. Peter Anvin" <hpa@zytor.com>
Cc: "Yan, Zheng" <zheng.z.yan@intel.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>,
linux-kernel@vger.kernel.org
Subject: RW and executable hole in page tables on x86_64
Date: Fri, 25 Oct 2013 06:34:54 -0700 [thread overview]
Message-ID: <20131025133454.GC4994@outflux.net> (raw)
Hi,
I've noticed there's a chunk of kernel memory still marked RW and x. See
0xffffffff82956000 below...
---[ High Kernel Mapping ]---
0xffffffff80000000-0xffffffff81000000 16M pmd
0xffffffff81000000-0xffffffff81a00000 10M ro PSE GLB x pmd
0xffffffff81a00000-0xffffffff81e00000 4M ro PSE GLB NX pmd
0xffffffff81e00000-0xffffffff82200000 4M RW GLB NX pte
0xffffffff82200000-0xffffffff82800000 6M RW PSE GLB NX pmd
0xffffffff82800000-0xffffffff82956000 1368K RW GLB NX pte
0xffffffff82956000-0xffffffff82a00000 680K RW GLB x pte
0xffffffff82a00000-0xffffffffa0000000 470M pmd
HPA looked at it for a bit, but it wasn't obvious what was going on. It's
after the end of bss. I do note that the two adjacent regions add up to
2MiB. Is this some kind of leftover mapping? What is this region? Is there
a sensible place to clean it up?
Thanks,
-Kees
--
Kees Cook @outflux.net
next reply other threads:[~2013-10-25 13:35 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-10-25 13:34 Kees Cook [this message]
2013-10-25 14:59 ` RW and executable hole in page tables on x86_64 H. Peter Anvin
2014-11-14 19:02 ` Kees Cook
2014-11-14 20:04 ` Thomas Gleixner
2014-11-14 20:15 ` Kees Cook
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