Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755925AbXJXCMU (ORCPT ); Tue, 23 Oct 2007 22:12:20 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753084AbXJXCMJ (ORCPT ); Tue, 23 Oct 2007 22:12:09 -0400 Received: from srv5.dvmed.net ([207.36.208.214]:45927 "EHLO mail.dvmed.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752803AbXJXCMG (ORCPT ); Tue, 23 Oct 2007 22:12:06 -0400 Message-ID: <471EA9D6.9000004@garzik.org> Date: Tue, 23 Oct 2007 22:11:34 -0400 From: Jeff Garzik User-Agent: Thunderbird 2.0.0.5 (X11/20070727) MIME-Version: 1.0 To: Herbert Xu CC: akpm@linux-foundation.org, torvalds@linux-foundation.org, matthew@wil.cx, arnd@arndb.de, ralf@linux-mips.org, adobriyan@gmail.com, viro@ftp.linux.org.uk, viro@zeniv.linux.org.uk, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org Subject: Re: [PATCH 1/2] irq_flags_t: intro and core annotations References: In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Spam-Score: -4.4 (----) X-Spam-Report: SpamAssassin version 3.1.9 on srv5.dvmed.net summary: Content analysis details: (-4.4 points, 5.0 required) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1164 Lines: 34 Herbert Xu wrote: > Jeff Garzik wrote: >> Let me add to the chorus of voices: I continually see two cases where >> real bugs crop up: >> >> 1) hacker uses spin_lock_irq() in incorrect context (where it is not >> safe to do a blind enable/disable) >> >> 2) hacker uses spin_lock_irq() correctly, but the surrounding code >> changes, thus invalidating prior assumptions. >> >> I would even go so far as to support the drastic measure of deleting >> spin_lock_irq(). >> >> spin_lock_irqsave() generates fewer bugs, is more future-proof, and by >> virtue of 'flags' permits architectures a bit more flexibility. > > Could we add a debug option that warned if spin_lock_irq is > executed with IRQs turned off already? Seems reasonable but perhaps arch-specific? Also, I think someone (akpm?) mentioned an effort had been made before, and run into some problems. I don't have details... Jeff - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/