diff options
| author | Nicholas Bellinger <nab@linux-iscsi.org> | 2013-10-25 10:44:15 -0700 |
|---|---|---|
| committer | Nicholas Bellinger <nab@linux-iscsi.org> | 2013-10-25 11:03:34 -0700 |
| commit | 60a01f558af9c48b0bb31f303c479e32721add3f (patch) | |
| tree | 8155f05d553ee5d7d22117cdbda4222939bc939e | |
| parent | 58932e96e438cd78f75e765d7b87ef39d3533d15 (diff) | |
| download | linux-60a01f558af9c48b0bb31f303c479e32721add3f.tar.bz2 | |
vhost/scsi: Fix incorrect usage of get_user_pages_fast write parameter
This patch addresses a long-standing bug where the get_user_pages_fast()
write parameter used for setting the underlying page table entry permission
bits was incorrectly set to write=1 for data_direction=DMA_TO_DEVICE, and
passed into get_user_pages_fast() via vhost_scsi_map_iov_to_sgl().
However, this parameter is intended to signal WRITEs to pinned userspace
PTEs for the virtio-scsi DMA_FROM_DEVICE -> READ payload case, and *not*
for the virtio-scsi DMA_TO_DEVICE -> WRITE payload case.
This bug would manifest itself as random process segmentation faults on
KVM host after repeated vhost starts + stops and/or with lots of vhost
endpoints + LUNs.
Cc: Stefan Hajnoczi <stefanha@redhat.com>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Asias He <asias@redhat.com>
Cc: <stable@vger.kernel.org> # 3.6+
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
| -rw-r--r-- | drivers/vhost/scsi.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c index ce5221fa393a..e663921eebb6 100644 --- a/drivers/vhost/scsi.c +++ b/drivers/vhost/scsi.c @@ -1056,7 +1056,7 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq) if (data_direction != DMA_NONE) { ret = vhost_scsi_map_iov_to_sgl(cmd, &vq->iov[data_first], data_num, - data_direction == DMA_TO_DEVICE); + data_direction == DMA_FROM_DEVICE); if (unlikely(ret)) { vq_err(vq, "Failed to map iov to sgl\n"); goto err_free; |