This is a note to let you know that I've just added the patch titled
xen-netback: BUG_ON in xenvif_rx_action() not catching overflow
to the 3.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
xen-netback-bug_on-in-xenvif_rx_action-not-catching-overflow.patch
and it can be found in the queue-3.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From foo@baz Thu Apr 10 20:31:46 PDT 2014
From: Paul Durrant <Paul.Durrant@xxxxxxxxxx>
Date: Fri, 28 Mar 2014 11:39:07 +0000
Subject: xen-netback: BUG_ON in xenvif_rx_action() not catching overflow
From: Paul Durrant <Paul.Durrant@xxxxxxxxxx>
[ Upstream commit 1425c7a4e8d3d2eebf308bcbdc3fa3c1247686b4 ]
The BUG_ON to catch ring overflow in xenvif_rx_action() makes the assumption
that meta_slots_used == ring slots used. This is not necessarily the case
for GSO packets, because the non-prefix GSO protocol consumes one more ring
slot than meta-slot for the 'extra_info'. This patch changes the test to
actually check ring slots.
Signed-off-by: Paul Durrant <paul.durrant@xxxxxxxxxx>
Cc: Ian Campbell <ian.campbell@xxxxxxxxxx>
Cc: Wei Liu <wei.liu2@xxxxxxxxxx>
Cc: Sander Eikelenboom <linux@xxxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/net/xen-netback/netback.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c
@@ -482,6 +482,8 @@ static void xenvif_rx_action(struct xenv
while ((skb = skb_dequeue(&vif->rx_queue)) != NULL) {
RING_IDX max_slots_needed;
+ RING_IDX old_req_cons;
+ RING_IDX ring_slots_used;
int i;
/* We need a cheap worse case estimate for the number of
@@ -530,8 +532,12 @@ static void xenvif_rx_action(struct xenv
vif->rx_last_skb_slots = 0;
sco = (struct skb_cb_overlay *)skb->cb;
+
+ old_req_cons = vif->rx.req_cons;
sco->meta_slots_used = xenvif_gop_skb(skb, &npo);
- BUG_ON(sco->meta_slots_used > max_slots_needed);
+ ring_slots_used = vif->rx.req_cons - old_req_cons;
+
+ BUG_ON(ring_slots_used > max_slots_needed);
__skb_queue_tail(&rxq, skb);
}
Patches currently in stable-queue which might be from Paul.Durrant@xxxxxxxxxx are
queue-3.14/xen-netback-bug_on-in-xenvif_rx_action-not-catching-overflow.patch
queue-3.14/xen-netback-worse-case-estimate-in-xenvif_rx_action-is-underestimating.patch
queue-3.14/xen-netback-remove-pointless-clause-from-if-statement.patch
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