From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2992656AbXCGWMc (ORCPT ); Wed, 7 Mar 2007 17:12:32 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S2992654AbXCGWMc (ORCPT ); Wed, 7 Mar 2007 17:12:32 -0500 Received: from e32.co.us.ibm.com ([32.97.110.150]:50199 "EHLO e32.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2992656AbXCGWMa (ORCPT ); Wed, 7 Mar 2007 17:12:30 -0500 Subject: Re: 2.6.21-rc2-mm2 hang From: Dave Hansen To: Andrew Morton Cc: linux-kernel@vger.kernel.org, Ingo Molnar , Suresh Siddha , Thomas Gleixner , Nick Piggin In-Reply-To: <20070306004408.d3f6434d.akpm@linux-foundation.org> References: <20070306004408.d3f6434d.akpm@linux-foundation.org> Content-Type: text/plain Date: Wed, 07 Mar 2007 14:12:16 -0800 Message-Id: <1173305536.868.8.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Evolution 2.6.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org I'm seeing weird hangs running ltp on 2.6.21-rc2-mm2. It manifests itself by the waitpid06 test in LTP hanging. This is very, very reproducible in about 5 seconds by adding '-s wait' to the ltp command line. I see 4 waitpid06 processes on my 4-way machine spinning in userspace. But, the weird part is that I can't ssh in once this happens, but I can log in to the console. I've bisected it down to: sched-fix-idle-load-balancing-in-softirqd-context http://sr71.net/~dave/linux/elm3b82-config sysrq-t: bash S 00000001 0 1670 1667 1676 (NOTLB) f761ff18 00000086 00000000 00000001 f7afb3ac c16f5f6c f761ff1c c0146eb5 e93d3067 fffb8000 f761ff20 c2d922e0 f7ec4030 f7ec413c 00006db1 1457ab10 00000025 c038eb60 fffffe00 f7ec4030 f7ec40e4 f761ff88 c011bc38 c014800d Call Trace: [] do_wait+0x271/0x316 [] sys_wait4+0x2f/0x31 [] sys_waitpid+0x27/0x2c [] syscall_call+0x7/0xb ======================= runltp S 00000001 0 1676 1670 1780 (NOTLB) f7625f18 00000082 00000000 00000001 f7adf3ac c16f5bec f7625f1c c0146eb5 e8cf4067 fffab000 f7625f20 c2d9a2e0 c30ee050 c30ee15c 00007d8f 3c8acf22 00000025 c309e560 fffffe00 c30ee050 c30ee104 f7625f88 c011bc38 c014800d Call Trace: [] do_wait+0x271/0x316 [] sys_wait4+0x2f/0x31 [] sys_waitpid+0x27/0x2c [] syscall_call+0x7/0xb ======================= pan S 00000000 0 1780 1676 1831 (NOTLB) f7639f30 00000086 00000000 00000000 00000000 00000246 f7ad095c f7f0e760 00000000 f7639f0c c0162748 c2d922e0 f7a0aab0 f7a0abbc 0000edaf abaf1d13 00000026 c038eb60 fffffe00 f7a0aab0 f7a0ab64 f7639fa0 c011bc38 e97e7065 Call Trace: [] do_wait+0x271/0x316 [] sys_wait4+0x2f/0x31 [] syscall_call+0x7/0xb ======================= waitpid06 S 00000001 0 1831 1780 1832 (NOTLB) f7637f18 00000082 00000000 00000001 f769b134 c16ed36c f7637f1c c0146eb5 f7a38c80 00000000 f7bce030 c2d9a2e0 f7e78030 f7e7813c 00000f64 abdcd3a1 00000026 f7bce030 fffffe00 f7e78030 f7e780e4 f7637f88 c011bc38 c014800d Call Trace: [] do_wait+0x271/0x316 [] sys_wait4+0x2f/0x31 [] sys_waitpid+0x27/0x2c [] syscall_call+0x7/0xb ======================= -- Dave