From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753452AbdLMB7z (ORCPT ); Tue, 12 Dec 2017 20:59:55 -0500 Received: from fldsmtpe03.verizon.com ([140.108.26.142]:44470 "EHLO fldsmtpe03.verizon.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753279AbdLMB66 (ORCPT ); Tue, 12 Dec 2017 20:58:58 -0500 From: alexander.levin@verizon.com Cc: Arnd Bergmann , Ladi Prosek , "Michael S . Tsirkin" , alexander.levin@verizon.com X-Host: surveyor.tdc.vzwcorp.com To: "linux-kernel@vger.kernel.org" , "stable@vger.kernel.org" Subject: [PATCH AUTOSEL for 4.9 060/100] virtio_balloon: prevent uninitialized variable use Thread-Topic: [PATCH AUTOSEL for 4.9 060/100] virtio_balloon: prevent uninitialized variable use Thread-Index: AQHTc7XAdtkCJqWYnkaufUWJvflwxA== Date: Wed, 13 Dec 2017 01:57:37 +0000 Message-ID: <20171213015722.6722-35-alexander.levin@verizon.com> References: <20171213015722.6722-1-alexander.levin@verizon.com> In-Reply-To: <20171213015722.6722-1-alexander.levin@verizon.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-messagesentrepresentingtype: 1 x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.144.60.250] Content-Type: text/plain; charset="iso-8859-1" MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from quoted-printable to 8bit by nfs id vBD200L3015173 From: Arnd Bergmann [ Upstream commit f0bb2d50dfcc519f06f901aac88502be6ff1df2c ] The latest gcc-7.0.1 snapshot reports a new warning: virtio/virtio_balloon.c: In function 'update_balloon_stats': virtio/virtio_balloon.c:258:26: error: 'events[2]' is used uninitialized in this function [-Werror=uninitialized] virtio/virtio_balloon.c:260:26: error: 'events[3]' is used uninitialized in this function [-Werror=uninitialized] virtio/virtio_balloon.c:261:56: error: 'events[18]' is used uninitialized in this function [-Werror=uninitialized] virtio/virtio_balloon.c:262:56: error: 'events[17]' is used uninitialized in this function [-Werror=uninitialized] This seems absolutely right, so we should add an extra check to prevent copying uninitialized stack data into the statistics. >>From all I can tell, this has been broken since the statistics code was originally added in 2.6.34. Fixes: 9564e138b1f6 ("virtio: Add memory statistics reporting to the balloon driver (V4)") Signed-off-by: Arnd Bergmann Signed-off-by: Ladi Prosek Signed-off-by: Michael S. Tsirkin Signed-off-by: Sasha Levin --- drivers/virtio/virtio_balloon.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c index 07b07b12ef90..a7c08cc4c1b7 100644 --- a/drivers/virtio/virtio_balloon.c +++ b/drivers/virtio/virtio_balloon.c @@ -253,12 +253,14 @@ static unsigned int update_balloon_stats(struct virtio_balloon *vb) available = si_mem_available(); +#ifdef CONFIG_VM_EVENT_COUNTERS update_stat(vb, idx++, VIRTIO_BALLOON_S_SWAP_IN, pages_to_bytes(events[PSWPIN])); update_stat(vb, idx++, VIRTIO_BALLOON_S_SWAP_OUT, pages_to_bytes(events[PSWPOUT])); update_stat(vb, idx++, VIRTIO_BALLOON_S_MAJFLT, events[PGMAJFAULT]); update_stat(vb, idx++, VIRTIO_BALLOON_S_MINFLT, events[PGFAULT]); +#endif update_stat(vb, idx++, VIRTIO_BALLOON_S_MEMFREE, pages_to_bytes(i.freeram)); update_stat(vb, idx++, VIRTIO_BALLOON_S_MEMTOT, -- 2.11.0