From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg0-f72.google.com (mail-pg0-f72.google.com [74.125.83.72]) by kanga.kvack.org (Postfix) with ESMTP id 126AF6B0038 for ; Sun, 26 Feb 2017 06:42:55 -0500 (EST) Received: by mail-pg0-f72.google.com with SMTP id 1so127103781pgz.5 for ; Sun, 26 Feb 2017 03:42:55 -0800 (PST) Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com. [148.163.156.1]) by mx.google.com with ESMTPS id l2si12482163pln.180.2017.02.26.03.42.53 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sun, 26 Feb 2017 03:42:54 -0800 (PST) Received: from pps.filterd (m0098394.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.20/8.16.0.20) with SMTP id v1QBdpNb064689 for ; Sun, 26 Feb 2017 06:42:53 -0500 Received: from e06smtp14.uk.ibm.com (e06smtp14.uk.ibm.com [195.75.94.110]) by mx0a-001b2d01.pphosted.com with ESMTP id 28u88puemg-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Sun, 26 Feb 2017 06:42:53 -0500 Received: from localhost by e06smtp14.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Sun, 26 Feb 2017 11:42:50 -0000 Date: Sun, 26 Feb 2017 12:42:44 +0100 (CET) From: Sebastian Ott Subject: [PATCH] mm, add_memory_resource: hold device_hotplug lock over mem_hotplug_{begin, done} MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Message-Id: Sender: owner-linux-mm@kvack.org List-ID: To: Dan Williams Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Andrew Morton , Heiko Carstens 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 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org