[PATCH] s390: qeth driver fixes [3/6]
[PATCH 6/9] s390: qeth driver fixes [3/6]
From: Frank Pavlic <fpavlic@de.ibm.com>
fixed kernel panic caused by qeth driver:
Using a bonding device qeth driver will realloc
headroom for every skb coming from the bond device.
Once this happens qeth frees the original skb and
set the skb pointer to the new realloced skb.
Under heavy transmit workload (e.g.UDP streams) through bond
network device the qdio output queue might get full.
In this case we return with EBUSY from qeth_send_packet.
Returning to qeth_hard_start_xmit routine
the skb address on the stack still points to the old address,
which has been freed before.
Returning from qeth_hard_start_xmit with EBUSY results in
requeuing the skb. In this case it corrupts the qdisc queue
and results in kernel panic.
Signed-off-by: Frank Pavlic <fpavlic@de.ibm.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
diff --git a/drivers/s390/net/qeth.h b/drivers/s390/net/qeth.h
index e8bd8c5..c04ee91 100644
--- a/drivers/s390/net/qeth.h
+++ b/drivers/s390/net/qeth.h
@@ -859,23 +859,18 @@
}
}
-static inline int
-qeth_realloc_headroom(struct qeth_card *card, struct sk_buff **skb, int size)
+static inline struct sk_buff *
+qeth_realloc_headroom(struct qeth_card *card, struct sk_buff *skb, int size)
{
- struct sk_buff *new_skb = NULL;
+ struct sk_buff *new_skb = skb;
- if (skb_headroom(*skb) < size){
- new_skb = skb_realloc_headroom(*skb, size);
- if (!new_skb) {
- PRINT_ERR("qeth_prepare_skb: could "
- "not realloc headroom for qeth_hdr "
- "on interface %s", QETH_CARD_IFNAME(card));
- return -ENOMEM;
- }
- kfree_skb(*skb);
- *skb = new_skb;
- }
- return 0;
+ if (skb_headroom(skb) >= size)
+ return skb;
+ new_skb = skb_realloc_headroom(skb, size);
+ if (!new_skb)
+ PRINT_ERR("Could not realloc headroom for qeth_hdr "
+ "on interface %s", QETH_CARD_IFNAME(card));
+ return new_skb;
}
static inline struct sk_buff *
@@ -885,16 +880,15 @@
if (!skb_cloned(skb))
return skb;
nskb = skb_copy(skb, pri);
- kfree_skb(skb); /* free our shared copy */
return nskb;
}
static inline void *
-qeth_push_skb(struct qeth_card *card, struct sk_buff **skb, int size)
+qeth_push_skb(struct qeth_card *card, struct sk_buff *skb, int size)
{
void *hdr;
- hdr = (void *) skb_push(*skb, size);
+ hdr = (void *) skb_push(skb, size);
/*
* sanity check, the Linux memory allocation scheme should
* never present us cases like this one (the qdio header size plus
@@ -903,8 +897,7 @@
if ((((unsigned long) hdr) & (~(PAGE_SIZE - 1))) !=
(((unsigned long) hdr + size +
QETH_IP_HEADER_SIZE) & (~(PAGE_SIZE - 1)))) {
- PRINT_ERR("qeth_prepare_skb: misaligned "
- "packet on interface %s. Discarded.",
+ PRINT_ERR("Misaligned packet on interface %s. Discarded.",
QETH_CARD_IFNAME(card));
return NULL;
}