linux-kernel - [PATCH] virtio_console: fix uninitialized variable use

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Message-ID: <1490819164-7648-1-git-send-email-mst@redhat.com>
Date:   Wed, 29 Mar 2017 23:27:16 +0300
From:   "Michael S. Tsirkin" <mst@...hat.com>
To:     linux-kernel@...r.kernel.org
Cc:     Mike Galbraith <efault@....de>, Arnd Bergmann <arnd@...db.de>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Amit Shah <amit@...nel.org>,
        virtualization@...ts.linux-foundation.org
Subject: [PATCH] virtio_console: fix uninitialized variable use

We try to disable callbacks on c_ivq even without multiport
even though that vq is not initialized in this configuration.

Fixes: c743d09dbd01 ("virtio: console: Disable callbacks for virtqueues at start of S4 freeze")
Suggested-by: Mike Galbraith <efault@....de>
Signed-off-by: Michael S. Tsirkin <mst@...hat.com>
---

Hi Mike
	if you like, pls send me your Signed-off-by and I'll
	change the patch to make you an author.
	More importantly, pls let me know whether this helps
	resolve the issues about hybernation for you!

 drivers/char/virtio_console.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c
index 5da4c8e..d0699c5 100644
--- a/drivers/char/virtio_console.c
+++ b/drivers/char/virtio_console.c
@@ -2202,14 +2202,16 @@ static int virtcons_freeze(struct virtio_device *vdev)
 
 	vdev->config->reset(vdev);
 
-	virtqueue_disable_cb(portdev->c_ivq);
+	if (use_multiport(portdev))
+		virtqueue_disable_cb(portdev->c_ivq);
 	cancel_work_sync(&portdev->control_work);
 	cancel_work_sync(&portdev->config_work);
 	/*
 	 * Once more: if control_work_handler() was running, it would
 	 * enable the cb as the last step.
 	 */
-	virtqueue_disable_cb(portdev->c_ivq);
+	if (use_multiport(portdev))
+		virtqueue_disable_cb(portdev->c_ivq);
 	remove_controlq_data(portdev);
 
 	list_for_each_entry(port, &portdev->ports, list) {
-- 
MST