From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Tue, 20 Nov 2007 19:00:46 +0000 (GMT) Received: from localhost.localdomain ([127.0.0.1]:1231 "EHLO dl5rb.ham-radio-op.net") by ftp.linux-mips.org with ESMTP id S20022090AbXKTTAo (ORCPT ); Tue, 20 Nov 2007 19:00:44 +0000 Received: from denk.linux-mips.net (denk.linux-mips.net [127.0.0.1]) by dl5rb.ham-radio-op.net (8.14.1/8.13.8) with ESMTP id lAKJ0grk028865; Tue, 20 Nov 2007 19:00:42 GMT Received: (from ralf@localhost) by denk.linux-mips.net (8.14.1/8.14.1/Submit) id lAKJ0fYL028864; Tue, 20 Nov 2007 19:00:41 GMT Date: Tue, 20 Nov 2007 19:00:41 +0000 From: Ralf Baechle To: David Daney Cc: Kaz Kylheku , linux-mips@linux-mips.org Subject: Re: futex_wake_op deadlock? Message-ID: <20071120190041.GA18138@linux-mips.org> References: <20071119184837.GA12287@linux-mips.org> <20071120112051.GB30675@linux-mips.org> <4743279B.7070402@avtrex.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4743279B.7070402@avtrex.com> User-Agent: Mutt/1.5.17 (2007-11-01) Return-Path: X-Envelope-To: <"|/home/ecartis/ecartis -s linux-mips"> (uid 0) X-Orcpt: rfc822;linux-mips@linux-mips.org Original-Recipient: rfc822;linux-mips@linux-mips.org X-archive-position: 17555 X-ecartis-version: Ecartis v1.0.0 Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org X-original-sender: ralf@linux-mips.org Precedence: bulk X-list: linux-mips On Tue, Nov 20, 2007 at 10:29:47AM -0800, David Daney wrote: >> Notice the branch at the end of the fixup code, it goes back to the >> SC instruction. The SC instruction took an exception so it will not have >> changed $1 so the loop will continue endless unless by coincidence the >> value to be stored from $1 happened to be zero. >> >> Obviously this one was MIPS specific and may hit all supported ABIs. So >> my initial suspicion this might be the issue David Miller recently >> discovered in the binary compat code isn't true. And it's a local DoS >> probably for all of 2.6.16 and up. >> > > I mostly similar code is in 2.6.15, so I think it is effected as well. > 2.6.12 on the other hand doesn't seem to have futex.h It originally appeared in the lmo kernel for 2.6.14-rc1 and a little after the 2.6.14 release in kernel.org. If I say 2.6.16 then it's simply that I don't ever look at anything that doesn't have a -stable branch. Ralf