From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756423AbYIKAAc (ORCPT ); Wed, 10 Sep 2008 20:00:32 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752591AbYIKAAV (ORCPT ); Wed, 10 Sep 2008 20:00:21 -0400 Received: from gateway-1237.mvista.com ([63.81.120.158]:17544 "EHLO gateway-1237.mvista.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752582AbYIKAAU (ORCPT ); Wed, 10 Sep 2008 20:00:20 -0400 Message-ID: <48C85F93.9020602@ct.jp.nec.com> Date: Wed, 10 Sep 2008 17:00:19 -0700 From: Hiroshi Shimamoto User-Agent: Thunderbird 2.0.0.16 (Windows/20080708) MIME-Version: 1.0 To: ronne@list.ru, mingo@elte.hu Cc: rml@tech9.net, linux-kernel@vger.kernel.org Subject: Re: deadlock in setting schedule parameters References: <48C838F9.1050607@list.ru> In-Reply-To: <48C838F9.1050607@list.ru> Content-Type: text/plain; charset=KOI8-R Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Andrei Gusev wrote: > Hello! > > I played witch scheduler settings. After doing something like: > echo -n 1000000 >sched_rt_period_us > > command is looked. I found in kernel.log > Sep 11 00:39:34 zaratustra > Sep 11 00:39:34 zaratustra Pid: 4495, comm: bash Tainted: G W > (2.6.26.3 #12) > Sep 11 00:39:34 zaratustra EIP: 0060:[] EFLAGS: 00210246 CPU: 0 > Sep 11 00:39:34 zaratustra EIP is at div64_u64+0x57/0x80 > Sep 11 00:39:34 zaratustra EAX: 0000389f EBX: 00000000 ECX: 00000000 > EDX: 00000000 > Sep 11 00:39:34 zaratustra ESI: d9800000 EDI: d9800000 EBP: 0000389f > ESP: ea7a6edc > Sep 11 00:39:34 zaratustra DS: 007b ES: 007b FS: 0000 GS: 0033 SS: 0068 > Sep 11 00:39:34 zaratustra Process bash (pid: 4495, ti=ea7a6000 > task=ea744000 task.ti=ea7a6000) > Sep 11 00:39:34 zaratustra Stack: 00000000 000003e8 d9800000 0000389f > c0119042 00000000 00000000 00000001 > Sep 11 00:39:34 zaratustra 00000000 00000000 ea7a6f54 00010000 00000000 > c04d2e80 00000001 000e7ef0 > Sep 11 00:39:34 zaratustra c01191a3 00000000 00000000 ea7a6fa0 00000001 > ffffffff c04d2e80 ea5b2480 > Sep 11 00:39:34 zaratustra Call Trace: > Sep 11 00:39:34 zaratustra [] __rt_schedulable+0x52/0x130 > Sep 11 00:39:34 zaratustra [] sched_rt_handler+0x83/0x120 > Sep 11 00:39:34 zaratustra [] proc_sys_call_handler+0xb6/0xd0 > Sep 11 00:39:34 zaratustra [] proc_sys_write+0x0/0x20 > Sep 11 00:39:34 zaratustra [] proc_sys_write+0x19/0x20 > Sep 11 00:39:34 zaratustra [] vfs_write+0xa8/0x140 > Sep 11 00:39:34 zaratustra [] sys_write+0x41/0x80 > Sep 11 00:39:34 zaratustra [] sysenter_past_esp+0x6a/0x91 > Sep 11 00:39:34 zaratustra ======================= > Sep 11 00:39:34 zaratustra Code: c8 41 0f ad f3 d3 ee f6 c1 20 0f 45 de > 31 f6 0f ad ef d3 ed f6 c1 20 0f 45 fd 0f 45 ee 31 c9 39 eb 89 fe 89 ea > 77 08 89 e8 31 d2 f3 89 c1 89 f0 8b 7c 24 08 f7 f3 8b 74 24 04 89 > ca 8b 1c 24 > Sep 11 00:39:34 zaratustra EIP: [] div64_u64+0x57/0x80 SS:ESP > 0068:ea7a6edc > Sep 11 00:39:34 zaratustra ---[ end trace 4eaa2a86a8e2da22 ]--- Hi, I'm not sure this patch really addresses the issue. But the kernel locks after changing sysctl_sched_rt_period=0. This patch is against -tip. I think it's needed to -stable too. --------> From: Hiroshi Shimamoto Subject: [PATCH] sched: do not allow sysctl_sched_rt_period=0 sysctl_sched_rt_period=0 makes exception at to_ratio(). Signed-off-by: Hiroshi Shimamoto --- kernel/sched.c | 6 ++++++ 1 files changed, 6 insertions(+), 0 deletions(-) diff --git a/kernel/sched.c b/kernel/sched.c index 8f4af55..32d56d6 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -8971,6 +8971,9 @@ static int sched_rt_global_constraints(void) u64 rt_runtime, rt_period; int ret = 0; + if (sysctl_sched_rt_period <= 0) + return -EINVAL; + rt_period = ktime_to_ns(tg->rt_bandwidth.rt_period); rt_runtime = tg->rt_bandwidth.rt_runtime; @@ -8988,6 +8991,9 @@ static int sched_rt_global_constraints(void) unsigned long flags; int i; + if (sysctl_sched_rt_period <= 0) + return -EINVAL; + spin_lock_irqsave(&def_rt_bandwidth.rt_runtime_lock, flags); for_each_possible_cpu(i) { struct rt_rq *rt_rq = &cpu_rq(i)->rt; -- 1.5.6