From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.6 required=3.0 tests=DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,T_DKIM_INVALID, URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5165CC433F5 for ; Wed, 5 Sep 2018 14:47:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 42DFC2077C for ; Wed, 5 Sep 2018 14:47:30 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=aepfle.de header.i=@aepfle.de header.b="rCgt5CGE" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 42DFC2077C Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=aepfle.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727792AbeIETR7 (ORCPT ); Wed, 5 Sep 2018 15:17:59 -0400 Received: from mo4-p00-ob.smtp.rzone.de ([85.215.255.24]:30195 "EHLO mo4-p00-ob.smtp.rzone.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727568AbeIETR7 (ORCPT ); Wed, 5 Sep 2018 15:17:59 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; t=1536158846; s=strato-dkim-0002; d=aepfle.de; h=References:In-Reply-To:Message-ID:Subject:Cc:To:From:Date: X-RZG-CLASS-ID:X-RZG-AUTH:From:Subject:Sender; bh=FTv0CyngqFs6Z+czb9UeIYUqDRo38KSm3DteWX8Kh5M=; b=rCgt5CGERmJI7udzJrNdyeTPg/ZX1Mi0A+werfHGILxWQR/BdxJ8ZpxAtHbmYn+I+d KbFmhl3Jhkicf10uVPYst0zMAMq/Ole3zEb7wlj4mq4ri1rK8XMLGtdrKuWhMyD/5GdD 3cVNVo5F2lWZeKS7mnf8j28RmrGP93dVkdCiYV7rL17NwaML+UrGSuSlT1KpbPF/ed+7 0oYRXKrYyFoD6MoLXAN2n5I+4SCAaOi1f72gU0jP23iyWIEKwlCUVp3AbL/VAML3HVZr 2FF8Wjlph9R7yTKEilavB4ElodSYo4UQbOVYaTycV+z6gYL7BQQUZD3lY7y02dV7NICk qA/A== X-RZG-AUTH: ":P2EQZWCpfu+qG7CngxMFH1J+3q8wa/QED/SSGq+wjGiUC4oc0Nr2ihluivsAQtyRsdRVZ54BGpAypu4eYvjwzPAqxRcXNDW+" X-RZG-CLASS-ID: mo00 Received: from sender by smtp.strato.de (RZmta 44.0 AUTH) with ESMTPSA id L0862bu85ElP6FA (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (curve secp521r1 with 521 ECDH bits, eq. 15360 bits RSA)) (Client did not present a certificate); Wed, 5 Sep 2018 16:47:25 +0200 (CEST) Date: Wed, 5 Sep 2018 16:47:19 +0200 From: Olaf Hering To: Juergen Gross Cc: xen-devel@lists.xenproject.org, Boris Ostrovsky , open list Subject: Re: [PATCH v1] xen: avoid crash in disable_hotplug_cpu Message-ID: <20180905164719.52e02256.olaf@aepfle.de> In-Reply-To: <7630aac8-8588-6e42-0807-f98b66ce37b5@suse.com> References: <20180905104039.13512-1-olaf@aepfle.de> <7630aac8-8588-6e42-0807-f98b66ce37b5@suse.com> X-Mailer: Claws Mail 3.16.1 (GTK+ 2.24.32; x86_64-suse-linux-gnu) MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; boundary="Sig_/LzNz=jnL/Kgv5MAft0yD6Bu"; protocol="application/pgp-signature" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --Sig_/LzNz=jnL/Kgv5MAft0yD6Bu Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable Am Wed, 5 Sep 2018 12:55:58 +0200 schrieb Juergen Gross : > Instead of trying to fight the symptoms, I think avoiding to offline > the last cpu would make more sense. Well, apparently the fix is to leave cpu#0 online because of a backtrace li= ke that: WARNING: CPU: 0 PID: 83 at kernel/sched/cpudeadline.c:159 cpudl_clear+0xa5/= 0xb0 Workqueue: events cpuset_hotplug_workfn RIP: e030:cpudl_clear+0xa5/0xb0 Code: 8b 43 48 c7 44 28 0c ff ff ff ff e8 d5 fd ff ff 48 8d 43 08 f0 4c 0f = ab 20 4c 89 ee 48 89 df 5b 5d 41 5c 41 5d e9 0b 3b 79 00 <0f> 0b e9 76 ff f= f ff 0f 1f 40 00 66 66 66 66 90 41 56 49 89 d6 41 RSP: e02b:ffffc900411cbc40 EFLAGS: 00010086 RAX: ffffffff810d09a0 RBX: ffff880106f1a100 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff880106f1a100 RBP: 0000000000000000 R08: 0000000000000000 R09: ffff8801068989b0 R10: ffff8801068989d0 R11: 0000000000000008 R12: 0000000000000000 R13: ffff8801f3800200 R14: 0000000000000001 R15: ffff8801f3823240 FS: 00007fd40d7f08c0(0000) GS:ffff8801f3800000(0000) knlGS:0000000000000000 CS: e033 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055eff60fe098 CR3: 00000001edf24000 CR4: 0000000000002660 Call Trace: rq_offline_dl+0x36/0x80 set_rq_offline+0x31/0x60 rq_attach_root+0x98/0xc0 cpu_attach_domain+0x107/0x320 partition_sched_domains+0x117/0x347 ? cpus_read_lock+0x2d/0x50 rebuild_sched_domains_locked+0xe4/0x4e0 ? __switch_to_asm+0x40/0x70 ? xen_mc_flush+0x102/0x210 rebuild_sched_domains+0x16/0x30 cpuset_hotplug_workfn+0x45e/0xef0 ? _raw_spin_unlock_irq+0x22/0x40 ? finish_task_switch+0x75/0x250 process_one_work+0x1fd/0x3e0 worker_thread+0x2d/0x3d0 ? rescuer_thread+0x340/0x340 kthread+0x112/0x130 ? kthread_create_worker_on_cpu+0x40/0x40 ret_from_fork+0x3a/0x50 Initially I did not spot it because the kernel was booted with 'quiet'. Olaf --Sig_/LzNz=jnL/Kgv5MAft0yD6Bu Content-Type: application/pgp-signature Content-Description: Digitale Signatur von OpenPGP -----BEGIN PGP SIGNATURE----- iF0EARECAB0WIQSkRyP6Rn//f03pRUBdQqD6ppg2fgUCW4/seAAKCRBdQqD6ppg2 firCAKCurqB2wJM0WzkYjLbfuoLzrMzuCwCgxQbHlvePNXf47mnN3+/vAXBwqwc= =cZSD -----END PGP SIGNATURE----- --Sig_/LzNz=jnL/Kgv5MAft0yD6Bu--