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=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 34E88C433FF for ; Mon, 5 Aug 2019 13:22:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 029C92067D for ; Mon, 5 Aug 2019 13:22:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1565011366; bh=abVtm5R4TC05I+ifUy0dsctYKFHWSDncpsOa7i8Gpus=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=kOBOclxp8PPMpGipJvJ+RWBveJ1MA8SrEnDsM/yZnbMgUekOEeS6ksbkJCGyAVisC ZDbUXrdhffbW8Ld/1rPZYZcJy00SyHvJlGfS1WvYCDdWYc9FxkZPulGF0+Atp4BRaY 2MXDN9ti9WX984zNM8dY3CA4P42jN/Zs7xalZyis= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730745AbfHENWo (ORCPT ); Mon, 5 Aug 2019 09:22:44 -0400 Received: from mail.kernel.org ([198.145.29.99]:59252 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729989AbfHENWk (ORCPT ); Mon, 5 Aug 2019 09:22:40 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 2D2E421871; Mon, 5 Aug 2019 13:22:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1565011359; bh=abVtm5R4TC05I+ifUy0dsctYKFHWSDncpsOa7i8Gpus=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=F7aimuNtg43x3v1JjLY8GRgBYpwTfhi3Qdmlfp89RAabddXyHjrFwuTFwU8A2xNu7 D3X82YPWVPsJ2tv0PIZ9KRjUvKL1F5SEGe3/QLkDELdW5F4FysYrANQgL/Rhzz6UVy Q1IuMTx9pc+iUA+pmtSUWVWgk5RwurCTXngRpowQ= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Pavel Tatashin , Dave Hansen , Bjorn Helgaas , Borislav Petkov , Dan Williams , Dave Hansen , Dave Jiang , David Hildenbrand , Fengguang Wu , Huang Ying , James Morris , =?UTF-8?q?J=C3=A9r=C3=B4me=20Glisse?= , Keith Busch , Michal Hocko , Ross Zwisler , Sasha Levin , Takashi Iwai , Tom Lendacky , Vishal Verma , Yaowei Bai , Andrew Morton , Linus Torvalds Subject: [PATCH 5.2 063/131] device-dax: fix memory and resource leak if hotplug fails Date: Mon, 5 Aug 2019 15:02:30 +0200 Message-Id: <20190805124955.668151080@linuxfoundation.org> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190805124951.453337465@linuxfoundation.org> References: <20190805124951.453337465@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org [ Upstream commit 31e4ca92a7dd4cdebd7fe1456b3b0b6ace9a816f ] Patch series ""Hotremove" persistent memory", v6. Recently, adding a persistent memory to be used like a regular RAM was added to Linux. This work extends this functionality to also allow hot removing persistent memory. We (Microsoft) have an important use case for this functionality. The requirement is for physical machines with small amount of RAM (~8G) to be able to reboot in a very short period of time (<1s). Yet, there is a userland state that is expensive to recreate (~2G). The solution is to boot machines with 2G preserved for persistent memory. Copy the state, and hotadd the persistent memory so machine still has all 8G available for runtime. Before reboot, offline and hotremove device-dax 2G, copy the memory that is needed to be preserved to pmem0 device, and reboot. The series of operations look like this: 1. After boot restore /dev/pmem0 to ramdisk to be consumed by apps. and free ramdisk. 2. Convert raw pmem0 to devdax ndctl create-namespace --mode devdax --map mem -e namespace0.0 -f 3. Hotadd to System RAM echo dax0.0 > /sys/bus/dax/drivers/device_dax/unbind echo dax0.0 > /sys/bus/dax/drivers/kmem/new_id echo online_movable > /sys/devices/system/memoryXXX/state 4. Before reboot hotremove device-dax memory from System RAM echo offline > /sys/devices/system/memoryXXX/state echo dax0.0 > /sys/bus/dax/drivers/kmem/unbind 5. Create raw pmem0 device ndctl create-namespace --mode raw -e namespace0.0 -f 6. Copy the state that was stored by apps to ramdisk to pmem device 7. Do kexec reboot or reboot through firmware if firmware does not zero memory in pmem0 region (These machines have only regular volatile memory). So to have pmem0 device either memmap kernel parameter is used, or devices nodes in dtb are specified. This patch (of 3): When add_memory() fails, the resource and the memory should be freed. Link: http://lkml.kernel.org/r/20190517215438.6487-2-pasha.tatashin@soleen.com Fixes: c221c0b0308f ("device-dax: "Hotplug" persistent memory for use like normal RAM") Signed-off-by: Pavel Tatashin Reviewed-by: Dave Hansen Cc: Bjorn Helgaas Cc: Borislav Petkov Cc: Dan Williams Cc: Dave Hansen Cc: Dave Jiang Cc: David Hildenbrand Cc: Fengguang Wu Cc: Huang Ying Cc: James Morris Cc: Jérôme Glisse Cc: Keith Busch Cc: Michal Hocko Cc: Ross Zwisler Cc: Sasha Levin Cc: Takashi Iwai Cc: Tom Lendacky Cc: Vishal Verma Cc: Yaowei Bai Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin --- drivers/dax/kmem.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/dax/kmem.c b/drivers/dax/kmem.c index a02318c6d28ab..4c0131857133d 100644 --- a/drivers/dax/kmem.c +++ b/drivers/dax/kmem.c @@ -66,8 +66,11 @@ int dev_dax_kmem_probe(struct device *dev) new_res->name = dev_name(dev); rc = add_memory(numa_node, new_res->start, resource_size(new_res)); - if (rc) + if (rc) { + release_resource(new_res); + kfree(new_res); return rc; + } return 0; } -- 2.20.1