From patchwork Wed Jan 27 00:11:39 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kamal Mostafa X-Patchwork-Id: 573634 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from huckleberry.canonical.com (huckleberry.canonical.com [91.189.94.19]) by ozlabs.org (Postfix) with ESMTP id 42B0E1402A8; Wed, 27 Jan 2016 11:15:24 +1100 (AEDT) Received: from localhost ([127.0.0.1] helo=huckleberry.canonical.com) by huckleberry.canonical.com with esmtp (Exim 4.76) (envelope-from ) id 1aODlY-0002x5-Mu; Wed, 27 Jan 2016 00:15:20 +0000 Received: from youngberry.canonical.com ([91.189.89.112]) by huckleberry.canonical.com with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.76) (envelope-from ) id 1aODi3-0000qD-Le for kernel-team@lists.ubuntu.com; Wed, 27 Jan 2016 00:11:43 +0000 Received: from 1.general.kamal.us.vpn ([10.172.68.52] helo=fourier) by youngberry.canonical.com with esmtpsa (TLS1.0:DHE_RSA_AES_128_CBC_SHA1:16) (Exim 4.76) (envelope-from ) id 1aODi3-0007Bx-8W; Wed, 27 Jan 2016 00:11:43 +0000 Received: from kamal by fourier with local (Exim 4.82) (envelope-from ) id 1aODi0-0004qa-Gb; Tue, 26 Jan 2016 16:11:40 -0800 From: Kamal Mostafa To: Minchan Kim Subject: [4.2.y-ckt stable] Patch "virtio_balloon: fix race by fill and leak" has been added to the 4.2.y-ckt tree Date: Tue, 26 Jan 2016 16:11:39 -0800 Message-Id: <1453853499-18602-1-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 1.9.1 X-Extended-Stable: 4.2 Cc: Kamal Mostafa , kernel-team@lists.ubuntu.com, "Michael S. Tsirkin" X-BeenThere: kernel-team@lists.ubuntu.com X-Mailman-Version: 2.1.14 Precedence: list List-Id: Kernel team discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: kernel-team-bounces@lists.ubuntu.com Sender: kernel-team-bounces@lists.ubuntu.com This is a note to let you know that I have just added a patch titled virtio_balloon: fix race by fill and leak to the linux-4.2.y-queue branch of the 4.2.y-ckt extended stable tree which can be found at: http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-4.2.y-queue This patch is scheduled to be released in version 4.2.8-ckt3. If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 4.2.y-ckt tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Kamal ---8<------------------------------------------------------------ From b96adf67cd5f1b27d6b182ca5bc3dd9ec2e4f5a8 Mon Sep 17 00:00:00 2001 From: Minchan Kim Date: Mon, 28 Dec 2015 08:35:12 +0900 Subject: virtio_balloon: fix race by fill and leak commit f68b992bbb474641881932c61c92dcfa6f5b3689 upstream. During my compaction-related stuff, I encountered a bug with ballooning. With repeated inflating and deflating cycle, guest memory( ie, cat /proc/meminfo | grep MemTotal) is decreased and couldn't be recovered. The reason is balloon_lock doesn't cover release_pages_balloon so struct virtio_balloon fields could be overwritten by race of fill_balloon(e,g, vb->*pfns could be critical). This patch fixes it in my test. Signed-off-by: Minchan Kim Signed-off-by: Michael S. Tsirkin Signed-off-by: Kamal Mostafa --- drivers/virtio/virtio_balloon.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) -- 1.9.1 diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c index 82e80e0..18fd1b2 100644 --- a/drivers/virtio/virtio_balloon.c +++ b/drivers/virtio/virtio_balloon.c @@ -205,8 +205,8 @@ static unsigned leak_balloon(struct virtio_balloon *vb, size_t num) */ if (vb->num_pfns != 0) tell_host(vb, vb->deflate_vq); - mutex_unlock(&vb->balloon_lock); release_pages_by_pfn(vb->pfns, vb->num_pfns); + mutex_unlock(&vb->balloon_lock); return num_freed_pages; }