Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751844AbaKYDXc (ORCPT ); Mon, 24 Nov 2014 22:23:32 -0500 Received: from p3plsmtps2ded03.prod.phx3.secureserver.net ([208.109.80.60]:56783 "EHLO p3plsmtps2ded03.prod.phx3.secureserver.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750784AbaKYDXb (ORCPT ); Mon, 24 Nov 2014 22:23:31 -0500 x-originating-ip: 72.167.245.219 From: Dexuan Cui To: gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, driverdev-devel@linuxdriverproject.org, olaf@aepfle.de, apw@canonical.com, jasowang@redhat.com, kys@microsoft.com Cc: haiyangz@microsoft.com Subject: [PATCH v2] hv: hv_balloon: avoid memory leak on alloc_error of 2MB memory block Date: Mon, 24 Nov 2014 20:32:43 -0800 Message-Id: <1416889963-31602-1-git-send-email-decui@microsoft.com> X-Mailer: git-send-email 1.7.4.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org If num_ballooned is not 0, we shouldn't neglect the already-partially-allocated 2MB memory block(s). Cc: Jason Wang Cc: K. Y. Srinivasan Signed-off-by: Dexuan Cui --- v2: I fixed the logic error in v1, pointed by Jason Wang: In v1: in the case of partially-allocated 2MB, alloc_error is true, so we'll run "done = true" and hence we won't proceed with the next iteration of trying 4K allocation. I also changed the WARN_ON to WARN_ON_ONCE in case the host behavior changes in the future. drivers/hv/hv_balloon.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/drivers/hv/hv_balloon.c b/drivers/hv/hv_balloon.c index 5e90c5d..b958ded 100644 --- a/drivers/hv/hv_balloon.c +++ b/drivers/hv/hv_balloon.c @@ -1087,10 +1087,12 @@ static void balloon_up(struct work_struct *dummy) struct dm_balloon_response *bl_resp; int alloc_unit; int ret; - bool alloc_error = false; + bool alloc_error; bool done = false; int i; + /* The host balloons pages in 2M granularity. */ + WARN_ON_ONCE(num_pages % PAGES_IN_2M != 0); /* * We will attempt 2M allocations. However, if we fail to @@ -1107,16 +1109,18 @@ static void balloon_up(struct work_struct *dummy) num_pages -= num_ballooned; + alloc_error = false; num_ballooned = alloc_balloon_pages(&dm_device, num_pages, bl_resp, alloc_unit, &alloc_error); - if ((alloc_error) && (alloc_unit != 1)) { + if (alloc_unit != 1 && num_ballooned == 0) { alloc_unit = 1; continue; } - if ((alloc_error) || (num_ballooned == num_pages)) { + if ((alloc_unit == 1 && alloc_error) || + (num_ballooned == num_pages)) { bl_resp->more_pages = 0; done = true; dm_device.state = DM_INITIALIZED; -- 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/