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=-4.0 required=3.0 tests=MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_PASS,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 F3D25C04AA7 for ; Mon, 13 May 2019 20:19:29 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 43A7D2085A for ; Mon, 13 May 2019 20:19:28 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 43A7D2085A Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=bugzilla.kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 452sbx6M8BzDqKh for ; Tue, 14 May 2019 06:19:25 +1000 (AEST) Authentication-Results: lists.ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=bugzilla.kernel.org (client-ip=198.145.29.98; helo=mail.wl.linuxfoundation.org; envelope-from=bugzilla-daemon@bugzilla.kernel.org; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=bugzilla.kernel.org Received: from mail.wl.linuxfoundation.org (mail.wl.linuxfoundation.org [198.145.29.98]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 452sZR5HQWzDqBX for ; Tue, 14 May 2019 06:18:07 +1000 (AEST) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 764662845C for ; Mon, 13 May 2019 20:18:04 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 6B0B02843C; Mon, 13 May 2019 20:18:04 +0000 (UTC) From: bugzilla-daemon@bugzilla.kernel.org To: linuxppc-dev@lists.ozlabs.org Subject: [Bug 203597] New: kernel 4.9.175 fails to boot on a PowerMac G4 3,6 at early stage Date: Mon, 13 May 2019 20:18:03 +0000 X-Bugzilla-Reason: None X-Bugzilla-Type: new X-Bugzilla-Watch-Reason: AssignedTo platform_ppc-32@kernel-bugs.osdl.org X-Bugzilla-Product: Platform Specific/Hardware X-Bugzilla-Component: PPC-32 X-Bugzilla-Version: 2.5 X-Bugzilla-Keywords: X-Bugzilla-Severity: normal X-Bugzilla-Who: erhard_f@mailbox.org X-Bugzilla-Status: NEW X-Bugzilla-Resolution: X-Bugzilla-Priority: P1 X-Bugzilla-Assigned-To: platform_ppc-32@kernel-bugs.osdl.org X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: bug_id short_desc product version cf_kernel_version rep_platform op_sys cf_tree bug_status bug_severity priority component assigned_to reporter cf_regression attachments.created Message-ID: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Bugzilla-URL: https://bugzilla.kernel.org/ Auto-Submitted: auto-generated MIME-Version: 1.0 X-Virus-Scanned: ClamAV using ClamSMTP X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" https://bugzilla.kernel.org/show_bug.cgi?id=3D203597 Bug ID: 203597 Summary: kernel 4.9.175 fails to boot on a PowerMac G4 3,6 at early stage Product: Platform Specific/Hardware Version: 2.5 Kernel Version: 4.9.175 Hardware: PPC-32 OS: Linux Tree: Mainline Status: NEW Severity: normal Priority: P1 Component: PPC-32 Assignee: platform_ppc-32@kernel-bugs.osdl.org Reporter: erhard_f@mailbox.org Regression: No Created attachment 282743 --> https://bugzilla.kernel.org/attachment.cgi?id=3D282743&action=3Dedit kernel .config (PowerMac G4 MDD) Trying out older kernels on the G4 MDD I noticed recent 4.9.x freeze the machine. Only message displayed in black letters on a white screen: done found display : /pco@f0000000/ATY,AlteracParent@10/ATY,Alterac_B@1, opening... It's a hard freeze, RCU_CPU_STALL_TIMEOUT does not kick in. Tried other stable kernels, which all worked: 4.19.37 4.14.114=20 4.4.179 So I suppose it's only a 4.9.x issue. Last working 4.9.x kernel I had in service was 4.9.161. First one I spotted freezing was 4.9.171. A bisect gav= e me the following commit: 1c38a84d45862be06ac418618981631eddbda741 is the first bad commit commit 1c38a84d45862be06ac418618981631eddbda741 Author: Michael Neuling Date: Thu Apr 11 21:45:59 2019 +1000 powerpc: Avoid code patching freed init sections commit 51c3c62b58b357e8d35e4cc32f7b4ec907426fe3 upstream. This stops us from doing code patching in init sections after they've been freed. In this chain: kvm_guest_init() -> kvm_use_magic_page() -> fault_in_pages_readable() -> __get_user() -> __get_user_nocheck() -> barrier_nospec(); We have a code patching location at barrier_nospec() and kvm_guest_init() is an init function. This whole chain gets inlined, so when we free the init section (hence kvm_guest_init()), this code goes away and hence should no longer be patched. We seen this as userspace memory corruption when using a memory checker while doing partition migration testing on powervm (this starts the code patching post migration via /sys/kernel/mobility/migration). In theory, it could also happen when using /sys/kernel/debug/powerpc/barrier_nospec. Cc: stable@vger.kernel.org # 4.13+ Signed-off-by: Michael Neuling Reviewed-by: Nicholas Piggin Reviewed-by: Christophe Leroy Signed-off-by: Michael Ellerman Signed-off-by: Sasha Levin --=20 You are receiving this mail because: You are watching the assignee of the bug.=