From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner+willy=40w.ods.org@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
	id S264132AbUAUVfo (ORCPT <rfc822;willy@w.ods.org>);
	Wed, 21 Jan 2004 16:35:44 -0500
Received: (majordomo@vger.kernel.org) by vger.kernel.org id S264163AbUAUVfo
	(ORCPT <rfc822;linux-kernel-outgoing>);
	Wed, 21 Jan 2004 16:35:44 -0500
Received: from fw.osdl.org ([65.172.181.6]:21380 "EHLO mail.osdl.org")
	by vger.kernel.org with ESMTP id S264132AbUAUVfe (ORCPT
	<rfc822;linux-kernel@vger.kernel.org>);
	Wed, 21 Jan 2004 16:35:34 -0500
Date: Wed, 21 Jan 2004 13:36:52 -0800
From: Andrew Morton <akpm@osdl.org>
To: Rui Saraiva <rmps@joel.ist.utl.pt>
Cc: linux-kernel@vger.kernel.org, acpi-devel@lists.sourceforge.net
Subject: Re: [2.6.2-rc1] sleep called from invalid context (8250/ACPI
 related?)
Message-Id: <20040121133652.04e02a13.akpm@osdl.org>
In-Reply-To: <Pine.LNX.4.58.0401211139001.13077@joel.ist.utl.pt>
References: <Pine.LNX.4.58.0401211139001.13077@joel.ist.utl.pt>
X-Mailer: Sylpheed version 0.9.7 (GTK+ 1.2.10; i586-pc-linux-gnu)
Mime-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
X-Mailing-List: linux-kernel@vger.kernel.org

Rui Saraiva <rmps@joel.ist.utl.pt> wrote:
>
> --------------------------------------------------------------------------------|
> 	Hello,
> 
> 	I've found this message in my logs while investigating some kernel Oops
> (in other message). If you need more info, please ask.
> 
> 	Regards,
> 		Rui Saraiva
> 
> 
> Debug: sleeping function called from invalid context at include/asm/semaphore.h:119
> in_atomic():1, irqs_disabled():0
> Call Trace:
>  [<c0122ddb>] __might_sleep+0xab/0xd0
>  [<d1bd2df6>] uart_unregister_port+0x76/0xa9 [serial_core]
>  [<d1bd9559>] unregister_serial+0x19/0x20 [8250]
>  [<d1bcb2de>] acpi_serial_remove+0x2e/0x50 [8250_acpi]
>  [<c02523f0>] acpi_driver_detach+0xcc/0x184
>  [<c0252621>] acpi_bus_unregister_driver+0x18/0x168
>  [<d1bcb312>] acpi_serial_exit+0x12/0x14 [8250_acpi]
>  [<c014510f>] sys_delete_module+0x13f/0x160
>  [<c0166307>] sys_munmap+0x57/0x80
>  [<c010a14f>] syscall_call+0x7/0xb

acpi_driver_detach is calling the acpi_driver.remove() method under
the acpi_device_lock spinlock.

uart_unregister_port() happens to be using a semaphore for its locking.

I do think that it would be better if ACPI were to permit this.  From a
quick peek it appears that acpi_device_lock can simply become a semaphore?