From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S266593AbUBLVCY (ORCPT ); Thu, 12 Feb 2004 16:02:24 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S266596AbUBLVAp (ORCPT ); Thu, 12 Feb 2004 16:00:45 -0500 Received: from ss1000-dmz.ms.mff.cuni.cz ([195.113.20.8]:44206 "EHLO ss1000.ms.mff.cuni.cz") by vger.kernel.org with ESMTP id S266593AbUBLU5M (ORCPT ); Thu, 12 Feb 2004 15:57:12 -0500 Date: Thu, 12 Feb 2004 21:57:08 +0100 From: Rudo Thomas To: linux-kernel@vger.kernel.org Subject: bug, or is it? - SCHED_RR and FPU related Message-ID: <20040212205708.GA1679@ss1000.ms.mff.cuni.cz> Mail-Followup-To: linux-kernel@vger.kernel.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.4i-ja.1 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hello. I have stumbled upon a grave bug, I think. I can reproduce a hard lock-up using xmms and a buggy plugin - only SysRq-B helps. I managed to narrow it down to "0.5/NAN"-like operation. It only causes a complete hang when xmms is run with SCHED_RR priority. Otherwise, only xmms hangs. Unfortunately, I was not able to create a working proof-of-concept program. The question is - is this a kernel bug, OR something that cannot be prevented from happening when using SCHED_RR policy? Tried with 2.6.3-rc[12] and glibc-2.3.2 (-r9 gentoo) with nptl support (if that matters). Have a nice day. Rudo.