From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner+w=401wt.eu-S1753309AbXDIR4L@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
	id S1753309AbXDIR4L (ORCPT <rfc822;w@1wt.eu>);
	Mon, 9 Apr 2007 13:56:11 -0400
Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753313AbXDIR4K
	(ORCPT <rfc822;linux-kernel-outgoing>);
	Mon, 9 Apr 2007 13:56:10 -0400
Received: from waste.org ([66.93.16.53]:55149 "EHLO waste.org"
	rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP
	id S1753309AbXDIR4J (ORCPT <rfc822;linux-kernel@vger.kernel.org>);
	Mon, 9 Apr 2007 13:56:09 -0400
Date: Mon, 9 Apr 2007 12:43:02 -0500
From: Matt Mackall <mpm@selenic.com>
To: Alexey Dobriyan <adobriyan@sw.ru>
Cc: akpm@osdl.org, linux-kernel@vger.kernel.org, devel@openvz.org
Subject: Re: /proc/*/pagemap BUG: sleeping function called from invalid context
Message-ID: <20070409174302.GP4892@waste.org>
References: <20070409082554.GB6532@localhost.sw.ru>
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20070409082554.GB6532@localhost.sw.ru>
User-Agent: Mutt/1.5.9i
Sender: linux-kernel-owner@vger.kernel.org
X-Mailing-List: linux-kernel@vger.kernel.org

On Mon, Apr 09, 2007 at 12:25:54PM +0400, Alexey Dobriyan wrote:
> After
> 	cat /proc/self/pagemap
> 
> BUG: sleeping function called from invalid context at include/asm/uaccess.h:453
> in_atomic():1, irqs_disabled():0
> 1 lock held by cat/14183:
>  #0:  (&mm->mmap_sem){----}, at: [<c017d17b>] pagemap_read+0x11f/0x21b
>  [<c01b7bc7>] copy_to_user+0x37/0x4c
>  [<c017cf92>] add_to_pagemap+0x49/0x6f
>  [<c017d034>] pagemap_pte_range+0x56/0x7e
>  [<c017cfde>] pagemap_pte_range+0x0/0x7e
>  [<c01b481d>] walk_page_range+0xf1/0x1a0
>  [<c017d1e3>] pagemap_read+0x187/0x21b
>  [<c01fdafa>] tty_write+0x1bb/0x1cc
>  [<c017d05c>] pagemap_read+0x0/0x21b
>  [<c01589b0>] vfs_read+0x72/0x95
>  [<c0158cce>] sys_read+0x41/0x67
>  [<c0103d96>] sysenter_past_esp+0x8f/0x99
>  [<c0103d66>] sysenter_past_esp+0x5f/0x99

I'm still waking up but this is odd. mm->mmap_sem is an rwsem,
sleeping inside of it should be perfectly valid.

Oh. You've got CONFIG_HIGHPTE and the note is really about the
kmap_atomic inside pte_offset_map. I'll fix that up.

-- 
Mathematics is the supreme nostalgia of our time.