iv/linux
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

vhost: scsi: add weight support

Browse Source 
commit c1ea02f15ab5efb3e93fc3144d895410bf79fcf2 upstream.

This patch will check the weight and exit the loop if we exceeds the
weight. This is useful for preventing scsi kthread from hogging cpu
which is guest triggerable.

This addresses CVE-2019-3900.

Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Stefan Hajnoczi <stefanha@redhat.com>
Fixes: 057cbf49a1f0 ("tcm_vhost: Initial merge for vhost level target fabric driver")
Signed-off-by: Jason Wang <jasowang@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
[bwh: Backported to 4.9:
 - Drop changes in vhost_scsi_ctl_handle_vq()
 - Adjust context]
Signed-off-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Jason Wang 2019-08-17 00:01:01 +01:00 committed by Greg Kroah-Hartman
parent 4b58628857
commit 02b40edda9
1 changed files with 3 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
drivers/vhost/scsi.c
View File

@ -851,7 +851,7 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
u64 tag;
u32 exp_data_len, data_direction;
unsigned out, in;
int head, ret, prot_bytes;
int head, ret, prot_bytes, c = 0;
size_t req_size, rsp_size = sizeof(struct virtio_scsi_cmd_resp);
size_t out_size, in_size;
u16 lun;
@ -870,7 +870,7 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
vhost_disable_notify(&vs->dev, vq);
for (;;) {
do {
head = vhost_get_vq_desc(vq, vq->iov,
ARRAY_SIZE(vq->iov), &out, &in,
NULL, NULL);
@ -1086,7 +1086,7 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
*/
INIT_WORK(&cmd->work, vhost_scsi_submission_work);
queue_work(vhost_scsi_workqueue, &cmd->work);
}
} while (likely(!vhost_exceeds_weight(vq, ++c, 0)));
out:
mutex_unlock(&vq->mutex);
}