From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932067AbbHMSuL (ORCPT ); Thu, 13 Aug 2015 14:50:11 -0400 Received: from aserp1040.oracle.com ([141.146.126.69]:48320 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751517AbbHMSuJ (ORCPT ); Thu, 13 Aug 2015 14:50:09 -0400 Message-ID: <55CCE638.3030907@oracle.com> Date: Thu, 13 Aug 2015 14:47:20 -0400 From: Sasha Levin User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.7.0 MIME-Version: 1.0 To: hpa@zytor.com, torvalds@linux-foundation.org, efault@gmx.de, tglx@linutronix.de, peterz@infradead.org, linux-kernel@vger.kernel.org, mingo@kernel.org, linux-tip-commits@vger.kernel.org Subject: Re: [tip:sched/core] sched: Change the sched_class::set_cpus_allowed( ) calling context References: <20150515154833.667516139@infradead.org> In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-Source-IP: userv0022.oracle.com [156.151.31.74] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 08/12/2015 08:38 AM, tip-bot for Peter Zijlstra wrote: > Commit-ID: 6c37067e27867db172b988cc11b9ff921175dee5 > Gitweb: http://git.kernel.org/tip/6c37067e27867db172b988cc11b9ff921175dee5 > Author: Peter Zijlstra > AuthorDate: Fri, 15 May 2015 17:43:36 +0200 > Committer: Ingo Molnar > CommitDate: Wed, 12 Aug 2015 12:06:10 +0200 > > sched: Change the sched_class::set_cpus_allowed() calling context > > Change the calling context of sched_class::set_cpus_allowed() such > that we can assume the task is inactive. > > This allows us to easily make changes that affect accounting done by > enqueue/dequeue. This does in fact completely remove > set_cpus_allowed_rt() and greatly reduces set_cpus_allowed_dl(). > > Signed-off-by: Peter Zijlstra (Intel) > Cc: Linus Torvalds > Cc: Mike Galbraith > Cc: Peter Zijlstra > Cc: Thomas Gleixner > Cc: dedekind1@gmail.com > Cc: juri.lelli@arm.com > Cc: mgorman@suse.de > Cc: riel@redhat.com > Cc: rostedt@goodmis.org > Link: http://lkml.kernel.org/r/20150515154833.667516139@infradead.org > Signed-off-by: Ingo Molnar Hey Peter, This patch breaks boot inside my VM: [79817.224383] bad: scheduling from the idle thread! [79817.224900] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.2.0-rc6-next-20150813-sasha-00040-g059fd6d #2431 [79817.225709] ffffffffae0c6320 ffff880051b77c00 ffffffffade7f739 ffff8800a69e15c0 [79817.226419] ffff880051b77c18 ffffffffa43c4ed3 ffff880051be8000 ffff880051b77c48 [79817.227122] ffffffffa43a7ffb ffff880051be8000 ffff8800a69e15c0 ffffffffae094d40 [79817.227806] Call Trace: [79817.228039] dump_stack (lib/dump_stack.c:52) [79817.228503] dequeue_task_idle (kernel/sched/idle_task.c:45) [79817.229005] dequeue_task (kernel/sched/core.c:839) [79817.229485] do_set_cpus_allowed (kernel/sched/core.c:1178 (discriminator 9)) [79817.230006] init_idle (kernel/sched/core.c:4937) [79817.230467] idle_thread_get (kernel/smpboot.c:35) [79817.230945] ? cpu_up (kernel/cpu.c:569) [79817.231374] _cpu_up (kernel/cpu.c:513) [79817.231801] ? cpu_down (kernel/cpu.c:500) [79817.232254] ? fork_idle (kernel/fork.c:1688) [79817.232731] ? find_next_bit (lib/find_bit.c:65) [79817.233216] ? idle_threads_init (include/linux/cpumask.h:189 kernel/smpboot.c:71) [79817.233715] cpu_up (kernel/cpu.c:574) [79817.234132] smp_init (kernel/smp.c:578) [79817.234557] kernel_init_freeable (init/main.c:690 init/main.c:884 init/main.c:1009) [79817.235095] ? start_kernel (init/main.c:979) [79817.235575] ? finish_task_switch (kernel/sched/sched.h:1087 kernel/sched/core.c:2526) [79817.236106] ? rest_init (init/main.c:934) [79817.236567] kernel_init (init/main.c:939) [79817.237020] ? rest_init (init/main.c:934) [79817.237496] ret_from_fork (arch/x86/entry/entry_64.S:473) [79817.237994] ? rest_init (init/main.c:934) [79817.238477] BUG: unable to handle kernel NULL pointer dereference at (null) [79817.239170] IP: [< (null)>] null) (??:?) [79817.239608] PGD 0 [79817.239802] Oops: 0010 [#1] SMP DEBUG_PAGEALLOC KASAN [79817.240295] Dumping ftrace buffer: [79817.240593] (ftrace buffer empty) [79817.240899] Modules linked in: [79817.241180] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.2.0-rc6-next-20150813-sasha-00040-g059fd6d #2431 [79817.241957] task: ffff880278228000 ti: ffff880051b70000 task.ti: ffff880051b70000 [79817.242573] RIP: [< (null)>] null) (??:?) [79817.243203] RSP: 0000:ffff880051b77c18 EFLAGS: 00010046 [79817.243646] RAX: dffffc0000000000 RBX: ffff880051be8000 RCX: 0000000000000004 [79817.244229] RDX: 0000000000000000 RSI: ffff880051be8000 RDI: ffff8800a69e15c0 [79817.244815] RBP: ffff880051b77c48 R08: 0000000000000001 R09: 0000000000000004 [79817.245404] R10: ffffed00ff815e03 R11: ffffed00ff815e01 R12: ffff8800a69e15c0 [79817.245987] R13: ffffffffae0c6320 R14: 0000000000000000 R15: 00004897e6254646 [79817.246577] FS: 0000000000000000(0000) GS:ffff880052600000(0000) knlGS:0000000000000000 [79817.247243] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b [79817.247723] CR2: 0000000000000000 CR3: 0000000030a2d000 CR4: 00000000000006b0 [79817.248319] Stack: [79817.248496] ffffffffa43a7d9b ffff880051be8000 ffff8800a69e15c0 ffffffffae0c6320 [79817.249176] ffff880051be8058 0000000000000001 ffff880051b77c88 ffffffffa43aab66 [79817.249850] ffff880051be8000 ffff8800a69e15c0 0000000000000001 0000000000000001 [79817.250521] Call Trace: [79817.250735] ? enqueue_task (kernel/sched/core.c:832) [79817.251211] do_set_cpus_allowed (kernel/sched/core.c:1189) [79817.251720] init_idle (kernel/sched/core.c:4937) [79817.252153] idle_thread_get (kernel/smpboot.c:35) [79817.252623] ? cpu_up (kernel/cpu.c:569) [79817.253045] _cpu_up (kernel/cpu.c:513) [79817.253471] ? cpu_down (kernel/cpu.c:500) [79817.253902] ? fork_idle (kernel/fork.c:1688) [79817.254354] ? find_next_bit (lib/find_bit.c:65) [79817.254820] ? idle_threads_init (include/linux/cpumask.h:189 kernel/smpboot.c:71) [79817.255326] cpu_up (kernel/cpu.c:574) [79817.255729] smp_init (kernel/smp.c:578) [79817.256158] kernel_init_freeable (init/main.c:690 init/main.c:884 init/main.c:1009) [79817.256675] ? start_kernel (init/main.c:979) [79817.257158] ? finish_task_switch (kernel/sched/sched.h:1087 kernel/sched/core.c:2526) [79817.257677] ? rest_init (init/main.c:934) [79817.258143] kernel_init (init/main.c:939) [79817.258604] ? rest_init (init/main.c:934) [79817.259094] ret_from_fork (arch/x86/entry/entry_64.S:473) [79817.259558] ? rest_init (init/main.c:934) [79817.260021] Code: Bad RIP value. Code starting with the faulting instruction =========================================== [79817.260342] RIP [< (null)>] null) (??:?) [79817.260791] RSP [79817.261098] CR2: 0000000000000000 [79817.261415] ---[ end trace eddc979a4104e4f3 ]--- [79817.261818] Kernel panic - not syncing: Fatal exception Thanks, Sasha