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=-7.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 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 4A2C6C433E0 for ; Fri, 5 Jun 2020 09:18:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 257722075B for ; Fri, 5 Jun 2020 09:18:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726257AbgFEJSj (ORCPT ); Fri, 5 Jun 2020 05:18:39 -0400 Received: from mx2.suse.de ([195.135.220.15]:36746 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726144AbgFEJSi (ORCPT ); Fri, 5 Jun 2020 05:18:38 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 55BAEAEE7; Fri, 5 Jun 2020 09:18:40 +0000 (UTC) Subject: Re: 5.7.0 / BUG: kernel NULL pointer dereference / setup_cpu_watcher To: Christian Kujau , linux-kernel@vger.kernel.org Cc: xen-devel@lists.xenproject.org References: From: =?UTF-8?B?SsO8cmdlbiBHcm/Dnw==?= Message-ID: <7e2dec0c-8e27-6454-7793-d1246262283d@suse.com> Date: Fri, 5 Jun 2020 11:18:36 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.8.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 05.06.20 10:36, Christian Kujau wrote: > Hi, > > I'm running a small Xen PVH domain and upgrading from vanilla 5.6.0 to > 5.7.0 caused the splat below, really early during boot. The configuration > has not changed, all new "make oldconfig" prompts have been answered with > "N". Old and new config, dmesg are here: > > http://nerdbynature.de/bits/5.7.0/ > > Searching the interwebs for similar reports didn't return much: > > * drm_sched_get_cleanup_job: BUG: kernel NULL pointer dereference > https://bugzilla.redhat.com/show_bug.cgi?id=1822984 -- but this > appears to be really DRM related. - https://lkml.org/lkml/2020/4/10/545 > > * A recent mm/vmstat patch, mentioning "device_offline" in its output > https://patchwork.kernel.org/patch/11563009/ > > But other than a few overlapping strings, I guess all of that is totally > unrelated :( Do you happen to start the guest with vcpus < maxvcpus? If yes there is already a patch pending for 5.8: https://git.kernel.org/pub/scm/linux/kernel/git/xen/tip.git/commit/?h=for-linus-5.8&id=c54b071c192dfe8061336f650ceaf358e6386e0b Juergen > > Thanks, > Christian. > > > Note: that "Xen Platform PCI: unrecognised magic value" on the top appears > in 5.6 kernels as well, but no ill effects so far. > > --------------------------------------------------------------- > Xen Platform PCI: unrecognised magic value > ACPI: No IOAPIC entries present > BUG: kernel NULL pointer dereference, address: 00000000000002d0 > #PF: supervisor read access in kernel mode > #PF: error_code(0x0000) - not-present page > PGD 0 P4D 0 > Oops: 0000 [#1] SMP PTI > CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.7.0 #2 > RIP: 0010:device_offline+0x8/0xf0 > Code: 48 89 e7 e8 3a ee f3 ff 4c 89 e0 48 83 c4 10 5b 41 5c c3 45 31 e4 48 83 c4 10 4c 89 e0 5b 41 5c c3 90 41 54 55 53 48 83 ec 10 87 d0 02 00 00 01 0f 85 ca 00 00 00 48 89 fb 48 8b 7f 48 48 85 > RSP: 0000:ffffbd9100013e78 EFLAGS: 00010286 > RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00000000820001fa > RDX: ffff9c9c3dd00000 RSI: 00000000820001fa RDI: 0000000000000000 > RBP: 0000000000000002 R08: 0000000000000001 R09: 0000000000000000 > R10: ffff9c9c3d5072a8 R11: 0000000000000000 R12: ffff9c9c3d594720 > R13: ffffffff8a57e5a8 R14: 0000000000000000 R15: 0000000000000000 > FS: 0000000000000000(0000) GS:ffff9c9c3dc00000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 00000000000002d0 CR3: 000000006b00a001 CR4: 00000000001606b0 > Call Trace: > setup_cpu_watcher+0x44/0x60 > ? plt_clk_driver_init+0xe/0xe > setup_vcpu_hotplug_event+0x23/0x26 > do_one_initcall+0x47/0x180 > kernel_init_freeable+0x13b/0x19d > ? rest_init+0x95/0x95 > kernel_init+0x5/0xeb > ret_from_fork+0x35/0x40 > Modules linked in: > CR2: 00000000000002d0 > ---[ end trace b0cc587db609787f ]--- >