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=-9.8 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT 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 A199AC432C3 for ; Sat, 16 Nov 2019 15:50:08 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 4C6E720885 for ; Sat, 16 Nov 2019 15:50:08 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="EZVD5cBW" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4C6E720885 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id EEB986B0271; Sat, 16 Nov 2019 10:50:07 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id E9AD46B0272; Sat, 16 Nov 2019 10:50:07 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D8A6C6B0273; Sat, 16 Nov 2019 10:50:07 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0025.hostedemail.com [216.40.44.25]) by kanga.kvack.org (Postfix) with ESMTP id C12E36B0271 for ; Sat, 16 Nov 2019 10:50:07 -0500 (EST) Received: from smtpin27.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with SMTP id 4E543180AD815 for ; Sat, 16 Nov 2019 15:50:07 +0000 (UTC) X-FDA: 76162576854.27.able40_3b341d3577659 X-HE-Tag: able40_3b341d3577659 X-Filterd-Recvd-Size: 11203 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf29.hostedemail.com (Postfix) with ESMTP for ; Sat, 16 Nov 2019 15:50:06 +0000 (UTC) Received: from sasha-vm.mshome.net (unknown [50.234.116.4]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 1BC3120857; Sat, 16 Nov 2019 15:50:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1573919405; bh=oWcwd+FN3BZWj+mOzGD/owj3Ghki+hBzbszw+PQoejY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=EZVD5cBWItpa/Ksuby/8zw8N2lckaVN1DDwtUXuVzQuR7ZgUnfRf65O0lwz/acagZ 85EGHpYwwsSN1RevPncs9mByRKogmKADwHqTI2udozy2QwLOGOVeL3aKedZ79x+l2K FMxtzODxOgTyxIi1FmhBlSY2w/5HdjxVUndIft2o= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: David Hildenbrand , Pavel Tatashin , "Rafael J . Wysocki" , Rashmica Gupta , Oscar Salvador , Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , "Rafael J. Wysocki" , Len Brown , Greg Kroah-Hartman , Boris Ostrovsky , Juergen Gross , Nathan Fontenot , John Allen , Michal Hocko , Dan Williams , Joonsoo Kim , Vlastimil Babka , Mathieu Malaterre , YASUAKI ISHIMATSU , Balbir Singh , Haiyang Zhang , Heiko Carstens , Jonathan Corbet , Kate Stewart , "K. Y. Srinivasan" , Martin Schwidefsky , Michael Neuling , Philippe Ombredanne , Stephen Hemminger , Thomas Gleixner , Andrew Morton , Linus Torvalds , Sasha Levin , linuxppc-dev@lists.ozlabs.org, linux-acpi@vger.kernel.org, linux-mm@kvack.org Subject: [PATCH AUTOSEL 4.14 104/150] mm/memory_hotplug: make add_memory() take the device_hotplug_lock Date: Sat, 16 Nov 2019 10:46:42 -0500 Message-Id: <20191116154729.9573-104-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20191116154729.9573-1-sashal@kernel.org> References: <20191116154729.9573-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: quoted-printable X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: From: David Hildenbrand [ Upstream commit 8df1d0e4a265f25dc1e7e7624ccdbcb4a6630c89 ] add_memory() currently does not take the device_hotplug_lock, however is aleady called under the lock from arch/powerpc/platforms/pseries/hotplug-memory.c drivers/acpi/acpi_memhotplug.c to synchronize against CPU hot-remove and similar. In general, we should hold the device_hotplug_lock when adding memory to synchronize against online/offline request (e.g. from user space) - whic= h already resulted in lock inversions due to device_lock() and mem_hotplug_lock - see 30467e0b3be ("mm, hotplug: fix concurrent memory hot-add deadlock"). add_memory()/add_memory_resource() will create memor= y block devices, so this really feels like the right thing to do. Holding the device_hotplug_lock makes sure that a memory block device can really only be accessed (e.g. via .online/.state) from user space, once the memory has been fully added to the system. The lock is not held yet in drivers/xen/balloon.c arch/powerpc/platforms/powernv/memtrace.c drivers/s390/char/sclp_cmd.c drivers/hv/hv_balloon.c So, let's either use the locked variants or take the lock. Don't export add_memory_resource(), as it once was exported to be used by XEN, which is never built as a module. If somebody requires it, we also have to export a locked variant (as device_hotplug_lock is never exported). Link: http://lkml.kernel.org/r/20180925091457.28651-3-david@redhat.com Signed-off-by: David Hildenbrand Reviewed-by: Pavel Tatashin Reviewed-by: Rafael J. Wysocki Reviewed-by: Rashmica Gupta Reviewed-by: Oscar Salvador Cc: Benjamin Herrenschmidt Cc: Paul Mackerras Cc: Michael Ellerman Cc: "Rafael J. Wysocki" Cc: Len Brown Cc: Greg Kroah-Hartman Cc: Boris Ostrovsky Cc: Juergen Gross Cc: Nathan Fontenot Cc: John Allen Cc: Michal Hocko Cc: Dan Williams Cc: Joonsoo Kim Cc: Vlastimil Babka Cc: Mathieu Malaterre Cc: Pavel Tatashin Cc: YASUAKI ISHIMATSU Cc: Balbir Singh Cc: Haiyang Zhang Cc: Heiko Carstens Cc: Jonathan Corbet Cc: Kate Stewart Cc: "K. Y. Srinivasan" Cc: Martin Schwidefsky Cc: Michael Neuling Cc: Philippe Ombredanne Cc: Stephen Hemminger Cc: Thomas Gleixner Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin --- .../platforms/pseries/hotplug-memory.c | 2 +- drivers/acpi/acpi_memhotplug.c | 2 +- drivers/base/memory.c | 9 ++++++-- drivers/xen/balloon.c | 3 +++ include/linux/memory_hotplug.h | 1 + mm/memory_hotplug.c | 22 ++++++++++++++++--- 6 files changed, 32 insertions(+), 7 deletions(-) diff --git a/arch/powerpc/platforms/pseries/hotplug-memory.c b/arch/power= pc/platforms/pseries/hotplug-memory.c index 93e09f108ca17..99a3cf51c5ba4 100644 --- a/arch/powerpc/platforms/pseries/hotplug-memory.c +++ b/arch/powerpc/platforms/pseries/hotplug-memory.c @@ -787,7 +787,7 @@ static int dlpar_add_lmb(struct of_drconf_cell *lmb) nid =3D memory_add_physaddr_to_nid(lmb->base_addr); =20 /* Add the memory */ - rc =3D add_memory(nid, lmb->base_addr, block_sz); + rc =3D __add_memory(nid, lmb->base_addr, block_sz); if (rc) { dlpar_remove_device_tree_lmb(lmb); return rc; diff --git a/drivers/acpi/acpi_memhotplug.c b/drivers/acpi/acpi_memhotplu= g.c index 6b0d3ef7309cb..2ccfbb61ca899 100644 --- a/drivers/acpi/acpi_memhotplug.c +++ b/drivers/acpi/acpi_memhotplug.c @@ -228,7 +228,7 @@ static int acpi_memory_enable_device(struct acpi_memo= ry_device *mem_device) if (node < 0) node =3D memory_add_physaddr_to_nid(info->start_addr); =20 - result =3D add_memory(node, info->start_addr, info->length); + result =3D __add_memory(node, info->start_addr, info->length); =20 /* * If the memory block has been used by the kernel, add_memory() diff --git a/drivers/base/memory.c b/drivers/base/memory.c index c617e00f4361d..8e5818e735e2f 100644 --- a/drivers/base/memory.c +++ b/drivers/base/memory.c @@ -517,15 +517,20 @@ memory_probe_store(struct device *dev, struct devic= e_attribute *attr, if (phys_addr & ((pages_per_block << PAGE_SHIFT) - 1)) return -EINVAL; =20 + ret =3D lock_device_hotplug_sysfs(); + if (ret) + goto out; + nid =3D memory_add_physaddr_to_nid(phys_addr); - ret =3D add_memory(nid, phys_addr, - MIN_MEMORY_BLOCK_SIZE * sections_per_block); + ret =3D __add_memory(nid, phys_addr, + MIN_MEMORY_BLOCK_SIZE * sections_per_block); =20 if (ret) goto out; =20 ret =3D count; out: + unlock_device_hotplug(); return ret; } =20 diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c index 7d521babc020b..71a6deeb4e714 100644 --- a/drivers/xen/balloon.c +++ b/drivers/xen/balloon.c @@ -356,7 +356,10 @@ static enum bp_state reserve_additional_memory(void) * callers drop the mutex before trying again. */ mutex_unlock(&balloon_mutex); + /* add_memory_resource() requires the device_hotplug lock */ + lock_device_hotplug(); rc =3D add_memory_resource(nid, resource, memhp_auto_online); + unlock_device_hotplug(); mutex_lock(&balloon_mutex); =20 if (rc) { diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplu= g.h index 58e110aee7ab4..d36a029353915 100644 --- a/include/linux/memory_hotplug.h +++ b/include/linux/memory_hotplug.h @@ -316,6 +316,7 @@ static inline void remove_memory(int nid, u64 start, = u64 size) {} =20 extern int walk_memory_range(unsigned long start_pfn, unsigned long end_= pfn, void *arg, int (*func)(struct memory_block *, void *)); +extern int __add_memory(int nid, u64 start, u64 size); extern int add_memory(int nid, u64 start, u64 size); extern int add_memory_resource(int nid, struct resource *resource, bool = online); extern int arch_add_memory(int nid, u64 start, u64 size, bool want_membl= ock); diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index c9d3a49bd4e20..4dfcee4a779f3 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -1110,7 +1110,12 @@ static int online_memory_block(struct memory_block= *mem, void *arg) return device_online(&mem->dev); } =20 -/* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLU= G */ +/* + * NOTE: The caller must call lock_device_hotplug() to serialize hotplug + * and online/offline operations (triggered e.g. by sysfs). + * + * we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLU= G + */ int __ref add_memory_resource(int nid, struct resource *res, bool online= ) { u64 start, size; @@ -1203,9 +1208,9 @@ int __ref add_memory_resource(int nid, struct resou= rce *res, bool online) mem_hotplug_done(); return ret; } -EXPORT_SYMBOL_GPL(add_memory_resource); =20 -int __ref add_memory(int nid, u64 start, u64 size) +/* requires device_hotplug_lock, see add_memory_resource() */ +int __ref __add_memory(int nid, u64 start, u64 size) { struct resource *res; int ret; @@ -1219,6 +1224,17 @@ int __ref add_memory(int nid, u64 start, u64 size) release_memory_resource(res); return ret; } + +int add_memory(int nid, u64 start, u64 size) +{ + int rc; + + lock_device_hotplug(); + rc =3D __add_memory(nid, start, size); + unlock_device_hotplug(); + + return rc; +} EXPORT_SYMBOL_GPL(add_memory); =20 #ifdef CONFIG_MEMORY_HOTREMOVE --=20 2.20.1