From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:34266 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752904AbcHRMpV (ORCPT ); Thu, 18 Aug 2016 08:45:21 -0400 Subject: Patch "balloon: check the number of available pages in leak balloon" has been added to the 4.7-stable tree To: kneumoin@virtuozzo.com, den@openvz.org, gregkh@linuxfoundation.org, mst@redhat.com Cc: , From: Date: Thu, 18 Aug 2016 14:45:04 +0200 Message-ID: <14715243044240@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled balloon: check the number of available pages in leak balloon to the 4.7-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: balloon-check-the-number-of-available-pages-in-leak-balloon.patch and it can be found in the queue-4.7 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From 37cf99e08c6fb4dcea0f9ad2b13b6daa8c76a711 Mon Sep 17 00:00:00 2001 From: Konstantin Neumoin Date: Mon, 11 Jul 2016 15:28:59 +0300 Subject: balloon: check the number of available pages in leak balloon From: Konstantin Neumoin commit 37cf99e08c6fb4dcea0f9ad2b13b6daa8c76a711 upstream. The balloon has a special mechanism that is subscribed to the oom notification which leads to deflation for a fixed number of pages. The number is always fixed even when the balloon is fully deflated. But leak_balloon did not expect that the pages to deflate will be more than taken, and raise a "BUG" in balloon_page_dequeue when page list will be empty. So, the simplest solution would be to check that the number of releases pages is less or equal to the number taken pages. Signed-off-by: Konstantin Neumoin Signed-off-by: Denis V. Lunev CC: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin Signed-off-by: Greg Kroah-Hartman --- drivers/virtio/virtio_balloon.c | 2 ++ 1 file changed, 2 insertions(+) --- a/drivers/virtio/virtio_balloon.c +++ b/drivers/virtio/virtio_balloon.c @@ -202,6 +202,8 @@ static unsigned leak_balloon(struct virt num = min(num, ARRAY_SIZE(vb->pfns)); mutex_lock(&vb->balloon_lock); + /* We can't release more pages than taken */ + num = min(num, (size_t)vb->num_pages); for (vb->num_pfns = 0; vb->num_pfns < num; vb->num_pfns += VIRTIO_BALLOON_PAGES_PER_PAGE) { page = balloon_page_dequeue(vb_dev_info); Patches currently in stable-queue which might be from kneumoin@virtuozzo.com are queue-4.7/balloon-check-the-number-of-available-pages-in-leak-balloon.patch