From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-1021398-1520488062-2-4556088640792304890 X-Sieve: CMU Sieve 3.0 X-Spam-known-sender: no X-Spam-score: 0.0 X-Spam-hits: BAYES_00 -1.9, HEADER_FROM_DIFFERENT_DOMAINS 0.25, RCVD_IN_DNSWL_HI -5, T_RP_MATCHES_RCVD -0.01, LANGUAGES en, BAYES_USED global, SA_VERSION 3.4.0 X-Spam-source: IP='209.132.180.67', Host='vger.kernel.org', Country='CN', FromHeader='com', MailFrom='org', XOriginatingCountry='US' X-Spam-charsets: plain='iso-8859-1' X-Resolved-to: greg@kroah.com X-Delivered-to: greg@kroah.com X-Mail-from: stable-owner@vger.kernel.org ARC-Seal: i=1; a=rsa-sha256; cv=none; d=messagingengine.com; s=arctest; t=1520488061; b=MmqGXvkfGjhzQem1tA9hPWZ46L7KZFsZIZlZcRc1Y8Ua3fs P12y8O+Z/E/Z+jZcYunuwPBGkYzZ9dZ67M4Ef5IlXxT+BLFtgh5WM5SCLK+D3/z/ 78cwlva/RZaPfigGoEgotb8Oz9FLQGetxBvayP7Mygpiu2K+tkjvd+SPT2WtCID/ bRONV2qFuKQr9Xka8rA74bIz22ptCx+tNOBIIBmyd4QBDAKtikAxPbXDRld0d8WY UuJI6EpqRP4RgSO5tXznD5xjRYdigzSjoMMCkGOQV0Kt9ItZUK3G+h2fznmEPeH4 dzy59fivkednL2CVofQqgywFTo9+L7sXQtgrvXQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=from:to:cc:subject:date:message-id :references:in-reply-to:content-type:content-transfer-encoding :mime-version:sender:list-id; s=arctest; t=1520488061; bh=x/kRyp 3/1HgOOP0BXungOsL3cHHTsjyavIj1VKbT6L4=; b=UBswA+WKCeQym78QAaZcrS ZDaykmI2X0wzqWKKw6dMhnN0fBDnZ5k2szJpwXb7aax/WCHylCbm1EQpAiLfTBqa voTh2hmO18NYzQvNtlwJgHCcLZrQuW1pFQ8hUidd+WzhmUIImp+CvgRqxhyC+OuZ o9KgAZjlc1coZPBu5jljSpVQAOyWZFiHAR4w/cI6Lw9Kyor/TJ0vqfMFElB+vIE5 uN3KIT2m0mFuPXarYeiK1AYQIT3iICpDkS7K3VrBjqLWDHFw8FUB9CIge3G7sgMO yNUMKv8WCGW+XNbgmyadvSTJigNm0lnMbYPU+ymYawmupOWv0u+1Bc3No7YIToRQ == ARC-Authentication-Results: i=1; mx2.messagingengine.com; arc=none (no signatures found); dkim=pass (1024-bit rsa key sha256) header.d=microsoft.com header.i=@microsoft.com header.b=RReXypti x-bits=1024 x-keytype=rsa x-algorithm=sha256 x-selector=selector1; dmarc=pass (p=reject,has-list-id=yes,d=none) header.from=microsoft.com; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-category=clean score=-100 state=0; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=microsoft.com header.result=pass header_is_org_domain=yes Authentication-Results: mx2.messagingengine.com; arc=none (no signatures found); dkim=pass (1024-bit rsa key sha256) header.d=microsoft.com header.i=@microsoft.com header.b=RReXypti x-bits=1024 x-keytype=rsa x-algorithm=sha256 x-selector=selector1; dmarc=pass (p=reject,has-list-id=yes,d=none) header.from=microsoft.com; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-category=clean score=-100 state=0; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=microsoft.com header.result=pass header_is_org_domain=yes Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965787AbeCHFFH (ORCPT ); Thu, 8 Mar 2018 00:05:07 -0500 Received: from mail-by2nam03on0127.outbound.protection.outlook.com ([104.47.42.127]:45712 "EHLO NAM03-BY2-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S935211AbeCHFFE (ORCPT ); Thu, 8 Mar 2018 00:05:04 -0500 From: Sasha Levin To: "linux-kernel@vger.kernel.org" , "stable@vger.kernel.org" CC: Stephen Boyd , Michael Turquette , Shawn Guo , Sasha Levin Subject: [PATCH AUTOSEL for 4.9 187/190] clk: Don't touch hardware when reparenting during registration Thread-Topic: [PATCH AUTOSEL for 4.9 187/190] clk: Don't touch hardware when reparenting during registration Thread-Index: AQHTtppYrQ0nPMAl6EuhPT26L3lLkg== Date: Thu, 8 Mar 2018 05:00:15 +0000 Message-ID: <20180308045810.8041-187-alexander.levin@microsoft.com> References: <20180308045810.8041-1-alexander.levin@microsoft.com> In-Reply-To: <20180308045810.8041-1-alexander.levin@microsoft.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [52.168.54.252] x-ms-publictraffictype: Email x-microsoft-exchange-diagnostics: 1;DM5PR2101MB0981;7:ScrHpI/1cSE9qfSiep123bQhd3Yw4oQ5i0cbamBPVRQ15Ydyv3f+chDv707ru6rU55kEkad7FbTyteuX4dt7hZiSWH+VudYuF5bwODEh3dapXTr/WcvrfSBeDdYXv/oaGVnOKRp/BeYqRPPpFGGMCMmwCCruvDhq8DdgpEmZy9tv1l9E6x+19HOsHQ/i3rw7MdZhnGJ4/z/FEY0uCtidvmoiA9Kr0OIfcNPk6jmo6vbPAenieo3oAHGf3T2IjZEa;20:mBEMbKQb9CZzyhA/A0d8Pzh3u09tbLzj0qLs11v+I49ZQuPziX3ComQxOiDFVJZpLNFIeF1aAsEwZDeKQEbSxes+X4OoSDLw3mENCgs4x3YEoH0yIaB+DgaSZPT9h3cBFC8Jcvv7P/433f3ZQ1xqmpHgI9vDsbkqiMRTXy1gYj4= x-ms-office365-filtering-ht: Tenant x-ms-office365-filtering-correlation-id: c27e13d5-e99a-4941-f3b7-08d584b22551 x-microsoft-antispam: UriScan:;BCL:0;PCL:0;RULEID:(7020095)(4652020)(48565401081)(5600026)(4604075)(3008032)(4534165)(4627221)(201703031133081)(201702281549075)(2017052603328)(7193020);SRVR:DM5PR2101MB0981; x-ms-traffictypediagnostic: DM5PR2101MB0981: authentication-results: spf=none (sender IP is ) smtp.mailfrom=Alexander.Levin@microsoft.com; x-microsoft-antispam-prvs: x-exchange-antispam-report-test: UriScan:(28532068793085)(89211679590171)(185117386973197); x-exchange-antispam-report-cfa-test: BCL:0;PCL:0;RULEID:(8211001083)(61425038)(6040501)(2401047)(8121501046)(5005006)(93006095)(93001095)(3231220)(944501244)(52105095)(10201501046)(3002001)(6055026)(61426038)(61427038)(6041288)(20161123562045)(20161123558120)(201703131423095)(201702281528075)(20161123555045)(201703061421075)(201703061406153)(20161123564045)(20161123560045)(6072148)(201708071742011);SRVR:DM5PR2101MB0981;BCL:0;PCL:0;RULEID:;SRVR:DM5PR2101MB0981; x-forefront-prvs: 060503E79B x-forefront-antispam-report: SFV:NSPM;SFS:(10019020)(39860400002)(39380400002)(396003)(366004)(346002)(376002)(199004)(189003)(305945005)(86612001)(2906002)(7736002)(6486002)(36756003)(54906003)(110136005)(6436002)(6666003)(2950100002)(10290500003)(316002)(186003)(22452003)(10090500001)(478600001)(105586002)(6512007)(53936002)(66066001)(68736007)(76176011)(102836004)(3280700002)(107886003)(25786009)(8936002)(59450400001)(106356001)(6506007)(5660300001)(3846002)(97736004)(14454004)(2501003)(26005)(5250100002)(4326008)(3660700001)(86362001)(575784001)(6116002)(81166006)(99286004)(72206003)(2900100001)(1076002)(8676002)(81156014)(22906009)(217873001);DIR:OUT;SFP:1102;SCL:1;SRVR:DM5PR2101MB0981;H:DM5PR2101MB1032.namprd21.prod.outlook.com;FPR:;SPF:None;PTR:InfoNoRecords;A:1;MX:1;LANG:en; x-microsoft-antispam-message-info: qoTpx5QiddeF93W2bDVkWUGx2r8KA3h2FNg3dD7hbdedMMn/a9A70rQ8VOx7tuIhOhxYROQLkpdOnX+BpJFc8dA7XObiBj8YxGNA8Ub+/gYOTzEe4K8en3o16vulCP0o51zuCrh+vzM2O77wUgSt8fFcBgiBlKQRz62zjb2ekA/Y3MSoY6qVvbqXfG5Nx8zG7Jygo1yaWlRXiAknEZh5lIw8KMpxkQOn8tZozIvyLlc42xMQihqwNgdw++jbOtqzC/5dzd5Hs+aCIx8JICN/17njqxys3x/0mjFHCjvVRrs1n17rwqlu3nbrbSvvN/yZhVpuf2Zs1w/BWYrbXAS6FQ== spamdiagnosticoutput: 1:99 spamdiagnosticmetadata: NSPM Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-OriginatorOrg: microsoft.com X-MS-Exchange-CrossTenant-Network-Message-Id: c27e13d5-e99a-4941-f3b7-08d584b22551 X-MS-Exchange-CrossTenant-originalarrivaltime: 08 Mar 2018 05:00:15.2501 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: 72f988bf-86f1-41af-91ab-2d7cd011db47 X-MS-Exchange-Transport-CrossTenantHeadersStamped: DM5PR2101MB0981 Sender: stable-owner@vger.kernel.org X-Mailing-List: stable@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-Mailing-List: linux-kernel@vger.kernel.org List-ID: From: Stephen Boyd [ Upstream commit f8f8f1d04494d3a6546bee3f0618c4dba31d7b72 ] The orphan clocks reparent operation shouldn't touch the hardware if clocks are enabled, otherwise it may get a chance to disable a newly registered critical clock which triggers the warning below. Assuming we have two clocks: A and B, B is the parent of A. Clock A has flag: CLK_OPS_PARENT_ENABLE Clock B has flag: CLK_IS_CRITICAL Step 1: Clock A is registered, then it becomes orphan. Step 2: Clock B is registered. Before clock B reach the critical clock enable operation, orphan A will find the newly registered parent B and do reparent operation, then parent B will be finally disabled in __clk_set_parent_after() due to CLK_OPS_PARENT_ENABLE flag as there's still no users of B which will then trigger the following warning. WARNING: CPU: 0 PID: 0 at drivers/clk/clk.c:597 clk_core_disable+0xb4/0xe0 Modules linked in: CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.11.0-rc1-00056-gdff1f66-dirty #= 1373 Hardware name: Generic DT based system Backtrace: [] (dump_backtrace) from [] (show_stack+0x18/0x1c) r6:600000d3 r5:00000000 r4:c0e26358 r3:00000000 [] (show_stack) from [] (dump_stack+0xb4/0xe8) [] (dump_stack) from [] (__warn+0xd8/0x104) r10:c0c21cd0 r9:c048aa78 r8:00000255 r7:00000009 r6:c0c1cd90 r5:00000000 r4:00000000 r3:c0e01d34 [] (__warn) from [] (warn_slowpath_null+0x28/0x30) r9:00000000 r8:ef00bf80 r7:c165ac4c r6:ef00bf80 r5:ef00bf80 r4:ef00bf80 [] (warn_slowpath_null) from [] (clk_core_disable+0xb4/= 0xe0) [] (clk_core_disable) from [] (clk_core_disable_lock+0x= 20/0x2c) r4:000000d3 r3:c0e0af00 [] (clk_core_disable_lock) from [] (clk_core_disable_un= prepare+0x14/0x28) r5:00000000 r4:ef00bf80 [] (clk_core_disable_unprepare) from [] (__clk_set_pare= nt_after+0x38/0x54) r4:ef00bd80 r3:000010a0 [] (__clk_set_parent_after) from [] (clk_register+0x4d0= /0x648) r6:ef00d500 r5:ef00bf80 r4:ef00bd80 r3:ef00bfd4 [] (clk_register) from [] (clk_hw_register+0x10/0x1c) r9:00000000 r8:00000003 r7:00000000 r6:00000824 r5:00000001 r4:ef00d500 [] (clk_hw_register) from [] (_register_divider+0xcc/0x= 120) [] (_register_divider) from [] (clk_register_divider+0x= 44/0x54) r10:00000004 r9:00000003 r8:00000001 r7:00000000 r6:00000003 r5:00000001 r4:f0810030 [] (clk_register_divider) from [] (imx7ulp_clocks_init+= 0x558/0xe98) r7:c0e296f8 r6:c165c808 r5:00000000 r4:c165c808 [] (imx7ulp_clocks_init) from [] (of_clk_init+0x118/0x1= e0) r10:00000001 r9:c0e01f68 r8:00000000 r7:c0e01f60 r6:ef7f8974 r5:ef0035c0 r4:00000006 [] (of_clk_init) from [] (time_init+0x2c/0x38) r10:efffed40 r9:c0d61a48 r8:c0e78000 r7:c0e07900 r6:ffffffff r5:c0e78000 r4:00000000 [] (time_init) from [] (start_kernel+0x218/0x394) [] (start_kernel) from [<6000807c>] (0x6000807c) r10:00000000 r9:410fc075 r8:6000406a r7:c0e0c930 r6:c0d61a44 r5:c0e07918 r4:c0e78294 We know that the clk isn't enabled with any sort of prepare_count here so we don't need to enable anything to prevent a race. And we're holding the prepare mutex so set_rate/set_parent can't race here either. Based on an earlier patch by Dong Aisheng. Fixes: fc8726a2c021 ("clk: core: support clocks which requires parents enab= le (part 2)") Cc: Michael Turquette Cc: Shawn Guo Reported-by: Dong Aisheng Signed-off-by: Stephen Boyd Signed-off-by: Sasha Levin --- drivers/clk/clk.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c index 0fb39fe217d1..097b0db43cbd 100644 --- a/drivers/clk/clk.c +++ b/drivers/clk/clk.c @@ -2443,14 +2443,17 @@ static int __clk_core_init(struct clk_core *core) */ hlist_for_each_entry_safe(orphan, tmp2, &clk_orphan_list, child_node) { struct clk_core *parent =3D __clk_init_parent(orphan); + unsigned long flags; =20 /* * we could call __clk_set_parent, but that would result in a * redundant call to the .set_rate op, if it exists */ if (parent) { - __clk_set_parent_before(orphan, parent); - __clk_set_parent_after(orphan, parent, NULL); + /* update the clk tree topology */ + flags =3D clk_enable_lock(); + clk_reparent(orphan, parent); + clk_enable_unlock(flags); __clk_recalc_accuracies(orphan); __clk_recalc_rates(orphan, 0); } --=20 2.14.1