linux-kernel - Re: 4.4-rc5: ugly warn on: 5 W+X pages found

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Message-ID: <20151214202627.GA15104@amd>
Date:	Mon, 14 Dec 2015 21:26:27 +0100
From:	Pavel Machek <pavel@....cz>
To:	Linus Torvalds <torvalds@...ux-foundation.org>
Cc:	Borislav Petkov <bp@...en8.de>,
	kernel list <linux-kernel@...r.kernel.org>,
	Stephen Smalley <sds@...ho.nsa.gov>,
	Andy Lutomirski <luto@...capital.net>,
	Arjan van de Ven <arjan@...ux.intel.com>,
	Brian Gerst <brgerst@...il.com>,
	Denys Vlasenko <dvlasenk@...hat.com>,
	Peter Anvin <hpa@...or.com>, Mike Galbraith <efault@....de>,
	Peter Zijlstra <peterz@...radead.org>,
	Thomas Gleixner <tglx@...utronix.de>
Subject: Re: 4.4-rc5: ugly warn on: 5 W+X pages found

Hi!

> > I know. But either someone cares, and it should be fixes, or noone
> > cares, and the check should be removed.
> 
> Someone cares, and it should be scheduled to be fixed for 4.5. The EFI
> mapping changes that were required to avoid the warning were much too
> big and late to make 4.4.
> 
> So for now, don't enable CONFIG_DEBUG_WX for now. Unless you want to
> actively debug the EFI mapping changes, that is. Which I heartily
> recommend people doing.

Ok, good, except... This is thinkpad X60. Good old BIOS. It should
have no EFI.

pavel@duo:~$ dmesg | grep EFI
pavel@duo:~$

>From the messages I got:

> [    3.285993] x86/mm: Found insecure W+X mapping at address
> ffe69000/0xffe69000

---[ Persisent kmap() Area ]---
0xffc00000-0xffd28000        1184K                               pte
0xffd28000-0xffddd000         724K     RW                 GLB NX pte
0xffddd000-0xffe69000         560K                               pte
0xffe69000-0xffe6e000          20K     RW                 GLB x  pte
0xffe6e000-0xffe6f000           4K                               pte
---[ Fixmap Area ]---

That is not EFI, right?

Thanks,
									Pavel


-- 
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