Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754783AbbL0XeP (ORCPT ); Sun, 27 Dec 2015 18:34:15 -0500 Received: from LGEAMRELO13.lge.com ([156.147.23.53]:45099 "EHLO lgeamrelo13.lge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754143AbbL0XeL (ORCPT ); Sun, 27 Dec 2015 18:34:11 -0500 X-Original-SENDERIP: 156.147.1.121 X-Original-MAILFROM: minchan@kernel.org X-Original-SENDERIP: 10.177.223.161 X-Original-MAILFROM: minchan@kernel.org From: Minchan Kim To: Andrew Morton Cc: "Michael S. Tsirkin" , linux-mm@kvack.org, linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, Konstantin Khlebnikov , Rafael Aquini , Minchan Kim , Subject: [PATCH 1/2] virtio_balloon: fix race by fill and leak Date: Mon, 28 Dec 2015 08:35:12 +0900 Message-Id: <1451259313-26353-1-git-send-email-minchan@kernel.org> X-Mailer: git-send-email 1.9.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1325 Lines: 41 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. Cc: Signed-off-by: Minchan Kim --- drivers/virtio/virtio_balloon.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c index 7efc32945810..7d3e5d0e9aa4 100644 --- a/drivers/virtio/virtio_balloon.c +++ b/drivers/virtio/virtio_balloon.c @@ -209,8 +209,8 @@ 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_balloon(vb); + mutex_unlock(&vb->balloon_lock); return num_freed_pages; } -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/