From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755395Ab2F1WDp (ORCPT ); Thu, 28 Jun 2012 18:03:45 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:42194 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753877Ab2F1WDn (ORCPT ); Thu, 28 Jun 2012 18:03:43 -0400 Date: Thu, 28 Jun 2012 15:03:42 -0700 From: Andrew Morton To: Robin Holt Cc: Dan Carpenter , linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org, Jack Steiner Subject: Re: [patch] sgi-xp: nested calls to spin_lock_irqsave() Message-Id: <20120628150342.aaa4ad2d.akpm@linux-foundation.org> In-Reply-To: <20120627135155.GA3464@sgi.com> References: <20120627135155.GA3464@sgi.com> X-Mailer: Sylpheed 3.0.2 (GTK+ 2.20.1; x86_64-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 List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 27 Jun 2012 08:51:55 -0500 Robin Holt wrote: > The code here has a nested spin_lock_irqsave(). It's not needed since > IRQs are already disabled and it causes a problem because it means that > IRQs won't be enabled again at the end. The second call to > spin_lock_irqsave() will overwrite the value of irq_flags and we can't > restore the proper settings. Please find large crayon and write on forehead "when fixing a bug, be sure to describe the end-user impact of that bug". Then others will have a chance of deciding whether the fix should be backported. > Signed-off-by: Dan Carpenter > Signed-off-by: Robin Holt I'm wondering if there should have been a Reported-by:dan in there. He's like that.