Re: [PATCH v3 2/2] virtio-scsi: add error handling

Hu Tao
2012-03-14T06:34:46Z

On Sun, Mar 11, 2012 at 01:47:11PM +0100, Paolo Bonzini wrote:
> Il 10/03/2012 09:48, Hu Tao ha scritto:
> > Is there a race here that the cmd may have been already freed (by
> > virtscsi_complete_free) after waking up from the completion?
>
> Looks right, can you submit with a Signed-off-by?
>

Here it is:

Fix a race in tmf path that the cmd may have been already freed
(by virtscsi_complete_free) after waking up from the completion.

Signed-off-by: Hu Tao <hutao@cn.fujitsu.com>
---
drivers/scsi/virtio_scsi.c | 10 ++++++----
1 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/scsi/virtio_scsi.c b/drivers/scsi/virtio_scsi.c
index 3f20678..7cba05d 100644
--- a/drivers/scsi/virtio_scsi.c
+++ b/drivers/scsi/virtio_scsi.c
@@ -175,7 +175,8 @@ static void virtscsi_complete_free(void *buf)

if (cmd->comp)
complete_all(cmd->comp);
- mempool_free(cmd, virtscsi_cmd_pool);
+ else
+ mempool_free(cmd, virtscsi_cmd_pool);
}

static void virtscsi_ctrl_done(struct virtqueue *vq)
@@ -305,7 +306,7 @@ out:
static int virtscsi_tmf(struct virtio_scsi *vscsi, struct virtio_scsi_cmd *cmd)
{
DECLARE_COMPLETION_ONSTACK(comp);
- int ret;
+ int ret = SUCCESS;

cmd->comp = &comp;
ret = virtscsi_kick_cmd(vscsi, vscsi->ctrl_vq, cmd);
@@ -315,9 +316,10 @@ static int virtscsi_tmf(struct virtio_scsi *vscsi, struct virtio_scsi_cmd *cmd)
wait_for_completion(&comp);
if (cmd->resp.tmf.response != VIRTIO_SCSI_S_OK &&
cmd->resp.tmf.response != VIRTIO_SCSI_S_FUNCTION_SUCCEEDED)
- return FAILED;
+ ret = FAILED;

- return SUCCESS;
+ mempool_free(cmd, virtscsi_cmd_pool);
+ return ret;
}

static int virtscsi_device_reset(struct scsi_cmnd *sc)
--
1.7.1