From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934152AbXC0Sb3 (ORCPT ); Tue, 27 Mar 2007 14:31:29 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S934157AbXC0SbA (ORCPT ); Tue, 27 Mar 2007 14:31:00 -0400 Received: from [198.99.130.12] ([198.99.130.12]:45434 "EHLO saraswathi.solana.com" rhost-flags-FAIL-FAIL-OK-OK) by vger.kernel.org with ESMTP id S934163AbXC0Saz (ORCPT ); Tue, 27 Mar 2007 14:30:55 -0400 Date: Tue, 27 Mar 2007 14:27:49 -0400 From: Jeff Dike To: Andrew Morton Cc: LKML , uml-devel Subject: [PATCH 5/6] UML - irq locking fixes Message-ID: <20070327182749.GA8416@c2.user-mode-linux.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.4.2.2i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org As the comment immediately preceding this points out, this list is changed in irq context, so it needs to be protected with spin_lock_irqsave in process context when it is processed. Sometimes, gcc should just compile the comments and forget the code. The IRQ side of this was better, in the sense that it blocked and unblocked interrupts, but it still should have saved and restored them. Signed-off-by: Jeff Dike -- arch/um/drivers/chan_kern.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) Index: linux-2.6.21-mm/arch/um/drivers/chan_kern.c =================================================================== --- linux-2.6.21-mm.orig/arch/um/drivers/chan_kern.c 2007-03-27 12:25:09.000000000 -0400 +++ linux-2.6.21-mm/arch/um/drivers/chan_kern.c 2007-03-27 12:56:21.000000000 -0400 @@ -235,11 +235,11 @@ void free_irqs(void) struct chan *chan; LIST_HEAD(list); struct list_head *ele; + unsigned long flags; - spin_lock_irq(&irqs_to_free_lock); + spin_lock_irqsave(&irqs_to_free_lock, flags); list_splice_init(&irqs_to_free, &list); - INIT_LIST_HEAD(&irqs_to_free); - spin_unlock_irq(&irqs_to_free_lock); + spin_unlock_irqrestore(&irqs_to_free_lock, flags); list_for_each(ele, &list){ chan = list_entry(ele, struct chan, free_list); @@ -254,13 +254,15 @@ void free_irqs(void) static void close_one_chan(struct chan *chan, int delay_free_irq) { + unsigned long flags; + if(!chan->opened) return; if(delay_free_irq){ - spin_lock_irq(&irqs_to_free_lock); + spin_lock_irqsave(&irqs_to_free_lock, flags); list_add(&chan->free_list, &irqs_to_free); - spin_unlock_irq(&irqs_to_free_lock); + spin_unlock_irqrestore(&irqs_to_free_lock, flags); } else { if(chan->input)