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vhost/scsi: Fix incorrect early vhost_scsi_handle_vq failures
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This patch fixes vhost_scsi_handle_vq() failure cases that result in BUG_ON()
getting triggered when vhost_scsi_free_cmd() is called, and ->tvc_se_cmd has
not been initialized by target_submit_cmd_map_sgls().

It changes tcm_vhost_release_cmd() to use tcm_vhost_cmd->tvc_nexus for obtaining
se_session pointer reference.  Also, avoid calling put_page() on NULL sg->page
entries in vhost_scsi_map_to_sgl() failure path.

Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
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Nicholas Bellinger committed Feb 4, 2015
1 parent 79c1414 commit de1419e
Showing 1 changed file with 29 additions and 23 deletions.
52 changes: 29 additions & 23 deletions drivers/vhost/scsi.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -462,7 +462,7 @@ static void tcm_vhost_release_cmd(struct se_cmd *se_cmd)
{
struct tcm_vhost_cmd *tv_cmd = container_of(se_cmd,
struct tcm_vhost_cmd, tvc_se_cmd);
struct se_session *se_sess = se_cmd->se_sess;
struct se_session *se_sess = tv_cmd->tvc_nexus->tvn_se_sess;
int i;

if (tv_cmd->tvc_sgl_count) {
Expand Down Expand Up @@ -864,9 +864,11 @@ vhost_scsi_map_iov_to_sgl(struct tcm_vhost_cmd *cmd,
ret = vhost_scsi_map_to_sgl(cmd, sg, sgl_count, &iov[i],
cmd->tvc_upages, write);
if (ret < 0) {
for (i = 0; i < cmd->tvc_sgl_count; i++)
put_page(sg_page(&cmd->tvc_sgl[i]));

for (i = 0; i < cmd->tvc_sgl_count; i++) {
struct page *page = sg_page(&cmd->tvc_sgl[i]);
if (page)
put_page(page);
}
cmd->tvc_sgl_count = 0;
return ret;
}
Expand Down Expand Up @@ -905,9 +907,11 @@ vhost_scsi_map_iov_to_prot(struct tcm_vhost_cmd *cmd,
ret = vhost_scsi_map_to_sgl(cmd, prot_sg, prot_sgl_count, &iov[i],
cmd->tvc_upages, write);
if (ret < 0) {
for (i = 0; i < cmd->tvc_prot_sgl_count; i++)
put_page(sg_page(&cmd->tvc_prot_sgl[i]));

for (i = 0; i < cmd->tvc_prot_sgl_count; i++) {
struct page *page = sg_page(&cmd->tvc_prot_sgl[i]);
if (page)
put_page(page);
}
cmd->tvc_prot_sgl_count = 0;
return ret;
}
Expand Down Expand Up @@ -1065,12 +1069,14 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
if (unlikely(vq->iov[0].iov_len < req_size)) {
pr_err("Expecting virtio-scsi header: %zu, got %zu\n",
req_size, vq->iov[0].iov_len);
break;
vhost_scsi_send_bad_target(vs, vq, head, out);
continue;
}
ret = memcpy_fromiovecend(req, &vq->iov[0], 0, req_size);
if (unlikely(ret)) {
vq_err(vq, "Faulted on virtio_scsi_cmd_req\n");
break;
vhost_scsi_send_bad_target(vs, vq, head, out);
continue;
}

/* virtio-scsi spec requires byte 0 of the lun to be 1 */
Expand Down Expand Up @@ -1101,14 +1107,16 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
if (data_direction != DMA_TO_DEVICE) {
vq_err(vq, "Received non zero do_pi_niov"
", but wrong data_direction\n");
goto err_cmd;
vhost_scsi_send_bad_target(vs, vq, head, out);
continue;
}
prot_bytes = vhost32_to_cpu(vq, v_req_pi.pi_bytesout);
} else if (v_req_pi.pi_bytesin) {
if (data_direction != DMA_FROM_DEVICE) {
vq_err(vq, "Received non zero di_pi_niov"
", but wrong data_direction\n");
goto err_cmd;
vhost_scsi_send_bad_target(vs, vq, head, out);
continue;
}
prot_bytes = vhost32_to_cpu(vq, v_req_pi.pi_bytesin);
}
Expand Down Expand Up @@ -1148,7 +1156,8 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
vq_err(vq, "Received SCSI CDB with command_size: %d that"
" exceeds SCSI_MAX_VARLEN_CDB_SIZE: %d\n",
scsi_command_size(cdb), TCM_VHOST_MAX_CDB_SIZE);
goto err_cmd;
vhost_scsi_send_bad_target(vs, vq, head, out);
continue;
}

cmd = vhost_scsi_get_tag(vq, tpg, cdb, tag, lun, task_attr,
Expand All @@ -1157,7 +1166,8 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
if (IS_ERR(cmd)) {
vq_err(vq, "vhost_scsi_get_tag failed %ld\n",
PTR_ERR(cmd));
goto err_cmd;
vhost_scsi_send_bad_target(vs, vq, head, out);
continue;
}

pr_debug("Allocated tv_cmd: %p exp_data_len: %d, data_direction"
Expand All @@ -1178,7 +1188,9 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
if (unlikely(ret)) {
vq_err(vq, "Failed to map iov to"
" prot_sgl\n");
goto err_free;
tcm_vhost_release_cmd(&cmd->tvc_se_cmd);
vhost_scsi_send_bad_target(vs, vq, head, out);
continue;
}
}
if (data_direction != DMA_NONE) {
Expand All @@ -1187,7 +1199,9 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
data_direction == DMA_FROM_DEVICE);
if (unlikely(ret)) {
vq_err(vq, "Failed to map iov to sgl\n");
goto err_free;
tcm_vhost_release_cmd(&cmd->tvc_se_cmd);
vhost_scsi_send_bad_target(vs, vq, head, out);
continue;
}
}
/*
Expand All @@ -1205,14 +1219,6 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
INIT_WORK(&cmd->work, tcm_vhost_submission_work);
queue_work(tcm_vhost_workqueue, &cmd->work);
}

mutex_unlock(&vq->mutex);
return;

err_free:
vhost_scsi_free_cmd(cmd);
err_cmd:
vhost_scsi_send_bad_target(vs, vq, head, out);
out:
mutex_unlock(&vq->mutex);
}
Expand Down

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