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=-5.6 required=3.0 tests=DATE_IN_PAST_06_12, DKIMWL_WL_HIGH,DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS, 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 263F8C7618B for ; Thu, 25 Jul 2019 05:51:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id F22DD2147A for ; Thu, 25 Jul 2019 05:51:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564033869; bh=2IhI4awjb8zpSmskBquFUnv/YYu8RV4VS6osttvV4k8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=UFonO5JX2UYOBDPILcD+KqbLuZyuiKBjDZrQF1agjSHPsWMG0JqpqDBnfA2Zw83jE WijoHvcYAgwAEjGjFGf0996WbhpdtZVpGH2cairiNIyhLK4oONb7RbnxFbLnmnMrYF o1Y3/8SC0DbeJ9c6wadHooDodP3u3g7YQaevMkVs= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2404776AbfGYFl4 (ORCPT ); Thu, 25 Jul 2019 01:41:56 -0400 Received: from mail.kernel.org ([198.145.29.99]:56794 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2404736AbfGYFl4 (ORCPT ); Thu, 25 Jul 2019 01:41:56 -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 30DA32075C; Thu, 25 Jul 2019 05:41:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564033315; bh=2IhI4awjb8zpSmskBquFUnv/YYu8RV4VS6osttvV4k8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=CrvFskvZB+qqK4UF4/C+GVaUCXZk7eOs1zHtMSH0aHXf324uj4DgWOckt0ncxvnMv 2igbMjkd6Tr+Y4S+HfVagfRbpLwnvh3kFwln1mzV2W1VsjCxZzcTJaQaH9YzyC5zfT b50IK11AQjZEH8k71VVkXC8+DBAo0AsEgTfnuBUU= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Juergen Gross Subject: [PATCH 4.19 164/271] xen: let alloc_xenballooned_pages() fail if not enough memory free Date: Wed, 24 Jul 2019 21:20:33 +0200 Message-Id: <20190724191709.210896989@linuxfoundation.org> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190724191655.268628197@linuxfoundation.org> References: <20190724191655.268628197@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Juergen Gross commit a1078e821b605813b63bf6bca414a85f804d5c66 upstream. Instead of trying to allocate pages with GFP_USER in add_ballooned_pages() check the available free memory via si_mem_available(). GFP_USER is far less limiting memory exhaustion than the test via si_mem_available(). This will avoid dom0 running out of memory due to excessive foreign page mappings especially on ARM and on x86 in PVH mode, as those don't have a pre-ballooned area which can be used for foreign mappings. As the normal ballooning suffers from the same problem don't balloon down more than si_mem_available() pages in one iteration. At the same time limit the default maximum number of retries. This is part of XSA-300. Signed-off-by: Juergen Gross Signed-off-by: Greg Kroah-Hartman --- drivers/xen/balloon.c | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-) --- a/drivers/xen/balloon.c +++ b/drivers/xen/balloon.c @@ -527,8 +527,15 @@ static void balloon_process(struct work_ state = reserve_additional_memory(); } - if (credit < 0) - state = decrease_reservation(-credit, GFP_BALLOON); + if (credit < 0) { + long n_pages; + + n_pages = min(-credit, si_mem_available()); + state = decrease_reservation(n_pages, GFP_BALLOON); + if (state == BP_DONE && n_pages != -credit && + n_pages < totalreserve_pages) + state = BP_EAGAIN; + } state = update_schedule(state); @@ -567,6 +574,9 @@ static int add_ballooned_pages(int nr_pa } } + if (si_mem_available() < nr_pages) + return -ENOMEM; + st = decrease_reservation(nr_pages, GFP_USER); if (st != BP_DONE) return -ENOMEM; @@ -696,7 +706,7 @@ static int __init balloon_init(void) balloon_stats.schedule_delay = 1; balloon_stats.max_schedule_delay = 32; balloon_stats.retry_count = 1; - balloon_stats.max_retry_count = RETRY_UNLIMITED; + balloon_stats.max_retry_count = 4; #ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG set_online_page_callback(&xen_online_page);