| Message ID | 1364916697-13212-1-git-send-email-asias@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Tue, Apr 02, 2013 at 11:31:37PM +0800, Asias He wrote: > In vhost_scsi_handle_vq: > > tv_tpg = vs->vs_tpg[target]; > if (!tv_tpg) { > .... > return > } > > tv_cmd = vhost_scsi_allocate_cmd(tv_tpg, &v_req, > > 1) vs->vs_tpg[target] might change after the NULL check and 2) the above > line might access tv_tpg from vs->vs_tpg[target]. To prevent 2), use > ACCESS_ONCE. Thanks mst for catching this up! > > Signed-off-by: Asias He <asias@redhat.com> OK this might be ok for 3.9. Acked-by: Michael S. Tsirkin <mst@redhat.com> Nicholas can you pick this up pls? For 3.10 I still think it's best to get rid of it and stick vs->vs_tpg in vq->private_data. > --- > drivers/vhost/tcm_vhost.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/vhost/tcm_vhost.c b/drivers/vhost/tcm_vhost.c > index 0524267..32d95e3 100644 > --- a/drivers/vhost/tcm_vhost.c > +++ b/drivers/vhost/tcm_vhost.c > @@ -668,7 +668,7 @@ static void vhost_scsi_handle_vq(struct vhost_scsi *vs, > > /* Extract the tpgt */ > target = v_req.lun[1]; > - tv_tpg = vs->vs_tpg[target]; > + tv_tpg = ACCESS_ONCE(vs->vs_tpg[target]); > > /* Target does not exist, fail the request */ > if (unlikely(!tv_tpg)) { > -- > 1.8.1.4 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Tue, 2013-04-02 at 18:39 +0300, Michael S. Tsirkin wrote: > On Tue, Apr 02, 2013 at 11:31:37PM +0800, Asias He wrote: > > In vhost_scsi_handle_vq: > > > > tv_tpg = vs->vs_tpg[target]; > > if (!tv_tpg) { > > .... > > return > > } > > > > tv_cmd = vhost_scsi_allocate_cmd(tv_tpg, &v_req, > > > > 1) vs->vs_tpg[target] might change after the NULL check and 2) the above > > line might access tv_tpg from vs->vs_tpg[target]. To prevent 2), use > > ACCESS_ONCE. Thanks mst for catching this up! > > > > Signed-off-by: Asias He <asias@redhat.com> > > OK this might be ok for 3.9. > > Acked-by: Michael S. Tsirkin <mst@redhat.com> > > Nicholas can you pick this up pls? > Applying to target-pending/master now. > For 3.10 I still think it's best to get rid of it > and stick vs->vs_tpg in vq->private_data. > Your call here. Given that vhost-scsi-pci code + Seabios w/ virtio-scsi enabled will be broken without Asias's two extra vq->private_data and initialize vq->last_used_idx changes on the list, they will certainly need to hit 3.9.x code once your happy to ACK for v3.10. Asias, I assume you'll be updating this soon..? --nab -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/vhost/tcm_vhost.c b/drivers/vhost/tcm_vhost.c index 0524267..32d95e3 100644 --- a/drivers/vhost/tcm_vhost.c +++ b/drivers/vhost/tcm_vhost.c @@ -668,7 +668,7 @@ static void vhost_scsi_handle_vq(struct vhost_scsi *vs, /* Extract the tpgt */ target = v_req.lun[1]; - tv_tpg = vs->vs_tpg[target]; + tv_tpg = ACCESS_ONCE(vs->vs_tpg[target]); /* Target does not exist, fail the request */ if (unlikely(!tv_tpg)) {
In vhost_scsi_handle_vq: tv_tpg = vs->vs_tpg[target]; if (!tv_tpg) { .... return } tv_cmd = vhost_scsi_allocate_cmd(tv_tpg, &v_req, 1) vs->vs_tpg[target] might change after the NULL check and 2) the above line might access tv_tpg from vs->vs_tpg[target]. To prevent 2), use ACCESS_ONCE. Thanks mst for catching this up! Signed-off-by: Asias He <asias@redhat.com> --- drivers/vhost/tcm_vhost.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)