From: Jeff Dike <jdike@addtoit.com>
To: Tom Spink <tspink@gmail.com>
Cc: LKML <linux-kernel@vger.kernel.org>
Subject: Re: UML fails to locate address space
Date: Tue, 20 May 2008 12:10:47 -0400 [thread overview]
Message-ID: <20080520161047.GA9598@c2.user-mode-linux.org> (raw)
In-Reply-To: <7b9198260805200659p6ed28403t9b0b0ea995f158d5@mail.gmail.com>
On Tue, May 20, 2008 at 02:59:14PM +0100, Tom Spink wrote:
> Attached. I guess the line of interest is:
>
> mmap2(NULL, 4096, PROT_READ|PROT_WRITE,
> MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = -1 EACCES (Permission
> denied)
Yup.
Can you try three things:
check the maps file for any arbitrary process
(i.e. /proc/$$/maps) and see if there's anything mapped at 0
gdb UML, stop it at that mmap, check its maps file and see if
there's anything mapped at 0
send me a pointer to the patches that Ubuntu has applied on
top of the stock kernel - I'm suspicious that they special-cased page
zero in order to ensure that NULL pointer dereferences cause faults.
You can test this last theory by initializing bottom to 4096 instead
of 0.
Jeff
--
Work email - jdike at linux dot intel dot com
next prev parent reply other threads:[~2008-05-20 16:16 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-05-20 11:08 UML fails to locate address space Tom Spink
2008-05-20 13:52 ` Jeff Dike
2008-05-20 13:59 ` Tom Spink
2008-05-20 16:10 ` Jeff Dike [this message]
2008-05-20 16:43 ` Tom Spink
2008-05-20 17:56 ` Jeff Dike
2008-05-20 18:01 ` Tom Spink
2008-05-20 19:24 ` Jeff Dike
2008-05-20 19:42 ` Tom Spink
2008-05-20 21:27 ` Jeff Dike
2008-05-20 22:03 ` Tom Spink
2008-05-20 23:57 ` Tom Spink
2008-05-21 1:58 ` Jeff Dike
2008-05-20 15:22 ` linux-os (Dick Johnson)
2008-05-20 17:35 ` Jeff Dike
2008-05-20 21:54 ` linux-os (Dick Johnson)
2008-05-21 2:15 ` Jeff Dike
2008-05-21 12:02 ` Tom Spink
2008-05-21 12:04 ` Tom Spink
2008-05-21 17:58 ` Jeff Dike
2008-05-21 19:01 ` Tom Spink
2008-05-20 21:58 ` linux-os (Dick Johnson)
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