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authorDavid Vrabel <david.vrabel@citrix.com>2013-02-14 03:18:58 +0000
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-02-28 06:59:06 -0800
commit29b3bb0be43fea0a49e5235894e1dcbc0ac299dc (patch)
treecee0a17f0637f7d2d7eb308d08163ccaf5cb12b0
parent320c1509197bce83d2ebb45d4cc5f9b4d91c05dc (diff)
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xen-netback: cancel the credit timer when taking the vif down
[ Upstream commit 3e55f8b306cf305832a4ac78aa82e1b40e818ece ] If the credit timer is left armed after calling xen_netbk_remove_xenvif(), then it may fire and attempt to schedule the vif which will then oops as vif->netbk == NULL. This may happen both in the fatal error path and during normal disconnection from the front end. The sequencing during shutdown is critical to ensure that: a) vif->netbk doesn't become unexpectedly NULL; and b) the net device/vif is not freed. 1. Mark as unschedulable (netif_carrier_off()). 2. Synchronously cancel the timer. 3. Remove the vif from the schedule list. 4. Remove it from it netback thread group. 5. Wait for vif->refcnt to become 0. Signed-off-by: David Vrabel <david.vrabel@citrix.com> Acked-by: Ian Campbell <ian.campbell@citrix.com> Reported-by: Christopher S. Aker <caker@theshore.net> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--drivers/net/xen-netback/interface.c3
1 files changed, 1 insertions, 2 deletions
diff --git a/drivers/net/xen-netback/interface.c b/drivers/net/xen-netback/interface.c
index b8c5193bd42..221f4265f7d 100644
--- a/drivers/net/xen-netback/interface.c
+++ b/drivers/net/xen-netback/interface.c
@@ -132,6 +132,7 @@ static void xenvif_up(struct xenvif *vif)
static void xenvif_down(struct xenvif *vif)
{
disable_irq(vif->irq);
+ del_timer_sync(&vif->credit_timeout);
xen_netbk_deschedule_xenvif(vif);
xen_netbk_remove_xenvif(vif);
}
@@ -363,8 +364,6 @@ void xenvif_disconnect(struct xenvif *vif)
atomic_dec(&vif->refcnt);
wait_event(vif->waiting_to_free, atomic_read(&vif->refcnt) == 0);
- del_timer_sync(&vif->credit_timeout);
-
if (vif->irq)
unbind_from_irqhandler(vif->irq, vif);