| Message ID | 1386079585-3469-1-git-send-email-paul.durrant@citrix.com |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
On Tue, Dec 03, 2013 at 02:06:25PM +0000, Paul Durrant wrote: > xenvif_start_xmit() relies on checking vif->task for NULL to determine > whether the vif is ready to accept packets. The task thread is stopped in > xenvif_disconnect() but task is not set to NULL. Thus, on a re-connect the > check will give a false positive. > > Also since commit ea732dff5cfa10789007bf4a5b935388a0bb2a8f (Handle backend > state transitions in a more robust way) it should not be possible for > xenvif_connect() to be called if the vif is already connected so change the > check of vif->tx_irq to a BUG_ON() and also add a BUG_ON(vif->task). > > Signed-off-by: Paul Durrant <paul.durrant@citrix.com> > Cc: Wei Liu <wei.liu2@citrix.com> > Cc: Ian Campbell <ian.campbell@citrix.com> > Cc: David Vrabel <david.vrabel@citrix.com> Acked-by: Wei Liu <wei.liu2@citrix.com> Thanks Wei. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
From: Paul Durrant <paul.durrant@citrix.com> Date: Tue, 3 Dec 2013 14:06:25 +0000 > xenvif_start_xmit() relies on checking vif->task for NULL to determine > whether the vif is ready to accept packets. The task thread is stopped in > xenvif_disconnect() but task is not set to NULL. Thus, on a re-connect the > check will give a false positive. > > Also since commit ea732dff5cfa10789007bf4a5b935388a0bb2a8f (Handle backend > state transitions in a more robust way) it should not be possible for > xenvif_connect() to be called if the vif is already connected so change the > check of vif->tx_irq to a BUG_ON() and also add a BUG_ON(vif->task). > > Signed-off-by: Paul Durrant <paul.durrant@citrix.com> Applied, thanks. -- To unsubscribe from this list: send the line "unsubscribe netdev" 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/net/xen-netback/interface.c b/drivers/net/xen-netback/interface.c index 2329ccc..870f1fa 100644 --- a/drivers/net/xen-netback/interface.c +++ b/drivers/net/xen-netback/interface.c @@ -368,11 +368,11 @@ int xenvif_connect(struct xenvif *vif, unsigned long tx_ring_ref, unsigned long rx_ring_ref, unsigned int tx_evtchn, unsigned int rx_evtchn) { + struct task_struct *task; int err = -ENOMEM; - /* Already connected through? */ - if (vif->tx_irq) - return 0; + BUG_ON(vif->tx_irq); + BUG_ON(vif->task); err = xenvif_map_frontend_rings(vif, tx_ring_ref, rx_ring_ref); if (err < 0) @@ -411,14 +411,16 @@ int xenvif_connect(struct xenvif *vif, unsigned long tx_ring_ref, } init_waitqueue_head(&vif->wq); - vif->task = kthread_create(xenvif_kthread, - (void *)vif, "%s", vif->dev->name); - if (IS_ERR(vif->task)) { + task = kthread_create(xenvif_kthread, + (void *)vif, "%s", vif->dev->name); + if (IS_ERR(task)) { pr_warn("Could not allocate kthread for %s\n", vif->dev->name); - err = PTR_ERR(vif->task); + err = PTR_ERR(task); goto err_rx_unbind; } + vif->task = task; + rtnl_lock(); if (!vif->can_sg && vif->dev->mtu > ETH_DATA_LEN) dev_set_mtu(vif->dev, ETH_DATA_LEN); @@ -461,8 +463,10 @@ void xenvif_disconnect(struct xenvif *vif) if (netif_carrier_ok(vif->dev)) xenvif_carrier_off(vif); - if (vif->task) + if (vif->task) { kthread_stop(vif->task); + vif->task = NULL; + } if (vif->tx_irq) { if (vif->tx_irq == vif->rx_irq)
xenvif_start_xmit() relies on checking vif->task for NULL to determine whether the vif is ready to accept packets. The task thread is stopped in xenvif_disconnect() but task is not set to NULL. Thus, on a re-connect the check will give a false positive. Also since commit ea732dff5cfa10789007bf4a5b935388a0bb2a8f (Handle backend state transitions in a more robust way) it should not be possible for xenvif_connect() to be called if the vif is already connected so change the check of vif->tx_irq to a BUG_ON() and also add a BUG_ON(vif->task). Signed-off-by: Paul Durrant <paul.durrant@citrix.com> Cc: Wei Liu <wei.liu2@citrix.com> Cc: Ian Campbell <ian.campbell@citrix.com> Cc: David Vrabel <david.vrabel@citrix.com> --- v2 - Make sure vif->task remains NULL in xenvif_connect() if kthread_create() fails - Fix patch comment drivers/net/xen-netback/interface.c | 20 ++++++++++++-------- 1 file changed, 12 insertions(+), 8 deletions(-)