From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752292AbdBZLnG (ORCPT ); Sun, 26 Feb 2017 06:43:06 -0500 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:53771 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752233AbdBZLm6 (ORCPT ); Sun, 26 Feb 2017 06:42:58 -0500 Date: Sun, 26 Feb 2017 12:42:44 +0100 (CET) From: Sebastian Ott X-X-Sender: sebott@schleppi.fritz.box To: Dan Williams cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Andrew Morton , Heiko Carstens Subject: [PATCH] mm, add_memory_resource: hold device_hotplug lock over mem_hotplug_{begin, done} User-Agent: Alpine 2.20 (LFD 67 2015-01-07) Organization: =?ISO-8859-15?Q?=22IBM_Deutschland_Research_&_Development_GmbH_=2F_Vorsitzende_des_Aufsichtsrats=3A_Martina_Koederitz_Gesch=E4ftsf=FChrung=3A_Dirk_Wittkopp_Sitz_der_Gesellschaft=3A_B=F6blingen_=2F_Registergericht?= =?ISO-8859-15?Q?=3A_Amtsgericht_Stuttgart=2C_HRB_243294=22?= MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII X-TM-AS-GCONF: 00 X-Content-Scanned: Fidelis XPS MAILER x-cbid: 17022611-0016-0000-0000-0000044616F0 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17022611-0017-0000-0000-0000269431FB Message-Id: X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2017-02-26_08:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=3 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1612050000 definitions=main-1702260121 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org With 4.10.0-10265-gc4f3f22 the following warning is triggered on s390: WARNING: CPU: 6 PID: 1 at drivers/base/core.c:643 assert_held_device_hotplug+0x4a/0x58 [ 5.731214] Call Trace: [ 5.731219] ([<000000000067b8b0>] assert_held_device_hotplug+0x40/0x58) [ 5.731225] [<0000000000337914>] mem_hotplug_begin+0x34/0xc8 [ 5.731231] [<00000000008b897e>] add_memory_resource+0x7e/0x1f8 [ 5.731236] [<00000000008b8bd2>] add_memory+0xda/0x130 [ 5.731243] [<0000000000d7f0dc>] add_memory_merged+0x15c/0x178 [ 5.731247] [<0000000000d7f3a6>] sclp_detect_standby_memory+0x2ae/0x2f8 [ 5.731252] [<00000000001002ba>] do_one_initcall+0xa2/0x150 [ 5.731258] [<0000000000d3adc0>] kernel_init_freeable+0x228/0x2d8 [ 5.731263] [<00000000008b6572>] kernel_init+0x2a/0x140 [ 5.731267] [<00000000008c3972>] kernel_thread_starter+0x6/0xc [ 5.731272] [<00000000008c396c>] kernel_thread_starter+0x0/0xc [ 5.731276] no locks held by swapper/0/1. [ 5.731280] Last Breaking-Event-Address: [ 5.731285] [<000000000067b8b6>] assert_held_device_hotplug+0x46/0x58 [ 5.731292] ---[ end trace 46480df21194c96a ]--- The following patch fixes that for me: ----->8 mm, add_memory_resource: hold device_hotplug lock over mem_hotplug_{begin, done} With commit 3fc219241 ("mm: validate device_hotplug is held for memory hotplug") a lock assertion was added to mem_hotplug_begin() which led to a warning when add_memory() is called. Fix this by acquiring device_hotplug_lock in add_memory_resource(). Signed-off-by: Sebastian Ott --- mm/memory_hotplug.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index 1d3ed58..c633bbc 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -1361,6 +1361,7 @@ int __ref add_memory_resource(int nid, struct resource *res, bool online) new_pgdat = !p; } + lock_device_hotplug(); mem_hotplug_begin(); /* @@ -1416,6 +1417,7 @@ int __ref add_memory_resource(int nid, struct resource *res, bool online) out: mem_hotplug_done(); + unlock_device_hotplug(); return ret; } EXPORT_SYMBOL_GPL(add_memory_resource); -- 2.3.0