path: root/drivers/s390/virtio
diff options
authorHalil Pasic <pasic@linux.ibm.com>2018-09-26 18:48:29 +0200
committerMichael S. Tsirkin <mst@redhat.com>2018-12-06 14:22:34 -0500
commit2448a299ec416a80f699940a86f4a6d9a4f643b1 (patch)
treeb679315127c7e5b490082e9162f58c408f4f06b4 /drivers/s390/virtio
parentvhost/vsock: fix reset orphans race with close timeout (diff)
virtio/s390: avoid race on vcdev->config
Currently we have a race on vcdev->config in virtio_ccw_get_config() and in virtio_ccw_set_config(). This normally does not cause problems, as these are usually infrequent operations. However, for some devices writing to/reading from the config space can be triggered through sysfs attributes. For these, userspace can force the race by increasing the frequency. Signed-off-by: Halil Pasic <pasic@linux.ibm.com> Cc: stable@vger.kernel.org Message-Id: <20180925121309.58524-2-pasic@linux.ibm.com> Signed-off-by: Cornelia Huck <cohuck@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Diffstat (limited to 'drivers/s390/virtio')
1 files changed, 8 insertions, 2 deletions
diff --git a/drivers/s390/virtio/virtio_ccw.c b/drivers/s390/virtio/virtio_ccw.c
index 97b6f197f007..c94f38ef9a94 100644
--- a/drivers/s390/virtio/virtio_ccw.c
+++ b/drivers/s390/virtio/virtio_ccw.c
@@ -828,6 +828,7 @@ static void virtio_ccw_get_config(struct virtio_device *vdev,
int ret;
struct ccw1 *ccw;
void *config_area;
+ unsigned long flags;
ccw = kzalloc(sizeof(*ccw), GFP_DMA | GFP_KERNEL);
if (!ccw)
@@ -846,11 +847,13 @@ static void virtio_ccw_get_config(struct virtio_device *vdev,
if (ret)
goto out_free;
+ spin_lock_irqsave(&vcdev->lock, flags);
memcpy(vcdev->config, config_area, offset + len);
- if (buf)
- memcpy(buf, &vcdev->config[offset], len);
if (vcdev->config_ready < offset + len)
vcdev->config_ready = offset + len;
+ spin_unlock_irqrestore(&vcdev->lock, flags);
+ if (buf)
+ memcpy(buf, config_area + offset, len);
@@ -864,6 +867,7 @@ static void virtio_ccw_set_config(struct virtio_device *vdev,
struct virtio_ccw_device *vcdev = to_vc_device(vdev);
struct ccw1 *ccw;
void *config_area;
+ unsigned long flags;
ccw = kzalloc(sizeof(*ccw), GFP_DMA | GFP_KERNEL);
if (!ccw)
@@ -876,9 +880,11 @@ static void virtio_ccw_set_config(struct virtio_device *vdev,
/* Make sure we don't overwrite fields. */
if (vcdev->config_ready < offset)
virtio_ccw_get_config(vdev, 0, NULL, offset);
+ spin_lock_irqsave(&vcdev->lock, flags);
memcpy(&vcdev->config[offset], buf, len);
/* Write the config area to the host. */
memcpy(config_area, vcdev->config, sizeof(vcdev->config));
+ spin_unlock_irqrestore(&vcdev->lock, flags);
ccw->cmd_code = CCW_CMD_WRITE_CONF;
ccw->flags = 0;
ccw->count = offset + len;