[075/104] IB: Fix RCU lockdep splats

From: Greg KH
Date: Wed Dec 07 2011 - 11:36:28 EST


3.1-stable review patch. If anyone has any objections, please let me know.

------------------

From: Eric Dumazet <eric.dumazet@xxxxxxxxx>

commit 580da35a31f91a594f3090b7a2c39b85cb051a12 upstream.

Commit f2c31e32b37 ("net: fix NULL dereferences in check_peer_redir()")
forgot to take care of infiniband uses of dst neighbours.

Many thanks to Marc Aurele who provided a nice bug report and feedback.

Reported-by: Marc Aurele La France <tsi@xxxxxxxxxxx>
Signed-off-by: Eric Dumazet <eric.dumazet@xxxxxxxxx>
Cc: David Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Roland Dreier <roland@xxxxxxxxxxxxxxx>

---
drivers/infiniband/core/addr.c | 9 ++++++---
drivers/infiniband/hw/cxgb3/iwch_cm.c | 4 ++++
drivers/infiniband/hw/cxgb4/cm.c | 4 ++++
drivers/infiniband/hw/mlx4/qp.c | 2 +-
drivers/infiniband/hw/nes/nes_cm.c | 6 ++++--
drivers/infiniband/ulp/ipoib/ipoib_main.c | 18 +++++++++++-------
drivers/infiniband/ulp/ipoib/ipoib_multicast.c | 6 ++++--
7 files changed, 34 insertions(+), 15 deletions(-)

--- a/drivers/infiniband/core/addr.c
+++ b/drivers/infiniband/core/addr.c
@@ -215,7 +215,9 @@ static int addr4_resolve(struct sockaddr

neigh = neigh_lookup(&arp_tbl, &rt->rt_gateway, rt->dst.dev);
if (!neigh || !(neigh->nud_state & NUD_VALID)) {
+ rcu_read_lock();
neigh_event_send(dst_get_neighbour(&rt->dst), NULL);
+ rcu_read_unlock();
ret = -ENODATA;
if (neigh)
goto release;
@@ -273,15 +275,16 @@ static int addr6_resolve(struct sockaddr
goto put;
}

+ rcu_read_lock();
neigh = dst_get_neighbour(dst);
if (!neigh || !(neigh->nud_state & NUD_VALID)) {
if (neigh)
neigh_event_send(neigh, NULL);
ret = -ENODATA;
- goto put;
+ } else {
+ ret = rdma_copy_addr(addr, dst->dev, neigh->ha);
}
-
- ret = rdma_copy_addr(addr, dst->dev, neigh->ha);
+ rcu_read_unlock();
put:
dst_release(dst);
return ret;
--- a/drivers/infiniband/hw/cxgb3/iwch_cm.c
+++ b/drivers/infiniband/hw/cxgb3/iwch_cm.c
@@ -1365,8 +1365,10 @@ static int pass_accept_req(struct t3cdev
goto reject;
}
dst = &rt->dst;
+ rcu_read_lock();
neigh = dst_get_neighbour(dst);
l2t = t3_l2t_get(tdev, neigh, neigh->dev);
+ rcu_read_unlock();
if (!l2t) {
printk(KERN_ERR MOD "%s - failed to allocate l2t entry!\n",
__func__);
@@ -1936,10 +1938,12 @@ int iwch_connect(struct iw_cm_id *cm_id,
}
ep->dst = &rt->dst;

+ rcu_read_lock();
neigh = dst_get_neighbour(ep->dst);

/* get a l2t entry */
ep->l2t = t3_l2t_get(ep->com.tdev, neigh, neigh->dev);
+ rcu_read_unlock();
if (!ep->l2t) {
printk(KERN_ERR MOD "%s - cannot alloc l2e.\n", __func__);
err = -ENOMEM;
--- a/drivers/infiniband/hw/cxgb4/cm.c
+++ b/drivers/infiniband/hw/cxgb4/cm.c
@@ -1358,6 +1358,7 @@ static int pass_accept_req(struct c4iw_d
goto reject;
}
dst = &rt->dst;
+ rcu_read_lock();
neigh = dst_get_neighbour(dst);
if (neigh->dev->flags & IFF_LOOPBACK) {
pdev = ip_dev_find(&init_net, peer_ip);
@@ -1384,6 +1385,7 @@ static int pass_accept_req(struct c4iw_d
rss_qid = dev->rdev.lldi.rxq_ids[
cxgb4_port_idx(neigh->dev) * step];
}
+ rcu_read_unlock();
if (!l2t) {
printk(KERN_ERR MOD "%s - failed to allocate l2t entry!\n",
__func__);
@@ -1909,6 +1911,7 @@ int c4iw_connect(struct iw_cm_id *cm_id,
}
ep->dst = &rt->dst;

+ rcu_read_lock();
neigh = dst_get_neighbour(ep->dst);

/* get a l2t entry */
@@ -1945,6 +1948,7 @@ int c4iw_connect(struct iw_cm_id *cm_id,
ep->rss_qid = ep->com.dev->rdev.lldi.rxq_ids[
cxgb4_port_idx(neigh->dev) * step];
}
+ rcu_read_unlock();
if (!ep->l2t) {
printk(KERN_ERR MOD "%s - cannot alloc l2e.\n", __func__);
err = -ENOMEM;
--- a/drivers/infiniband/hw/mlx4/qp.c
+++ b/drivers/infiniband/hw/mlx4/qp.c
@@ -1309,7 +1309,7 @@ static int build_mlx_header(struct mlx4_
int is_eth;
int is_vlan = 0;
int is_grh;
- u16 vlan;
+ u16 vlan = 0;

send_size = 0;
for (i = 0; i < wr->num_sge; ++i)
--- a/drivers/infiniband/hw/nes/nes_cm.c
+++ b/drivers/infiniband/hw/nes/nes_cm.c
@@ -1150,9 +1150,11 @@ static int nes_addr_resolve_neigh(struct
neigh_release(neigh);
}

- if ((neigh == NULL) || (!(neigh->nud_state & NUD_VALID)))
+ if ((neigh == NULL) || (!(neigh->nud_state & NUD_VALID))) {
+ rcu_read_lock();
neigh_event_send(dst_get_neighbour(&rt->dst), NULL);
-
+ rcu_read_unlock();
+ }
ip_rt_put(rt);
return rc;
}
--- a/drivers/infiniband/ulp/ipoib/ipoib_main.c
+++ b/drivers/infiniband/ulp/ipoib/ipoib_main.c
@@ -555,6 +555,7 @@ static int path_rec_start(struct net_dev
return 0;
}

+/* called with rcu_read_lock */
static void neigh_add_path(struct sk_buff *skb, struct net_device *dev)
{
struct ipoib_dev_priv *priv = netdev_priv(dev);
@@ -636,6 +637,7 @@ err_drop:
spin_unlock_irqrestore(&priv->lock, flags);
}

+/* called with rcu_read_lock */
static void ipoib_path_lookup(struct sk_buff *skb, struct net_device *dev)
{
struct ipoib_dev_priv *priv = netdev_priv(skb->dev);
@@ -720,13 +722,14 @@ static int ipoib_start_xmit(struct sk_bu
struct neighbour *n = NULL;
unsigned long flags;

+ rcu_read_lock();
if (likely(skb_dst(skb)))
n = dst_get_neighbour(skb_dst(skb));

if (likely(n)) {
if (unlikely(!*to_ipoib_neigh(n))) {
ipoib_path_lookup(skb, dev);
- return NETDEV_TX_OK;
+ goto unlock;
}

neigh = *to_ipoib_neigh(n);
@@ -749,17 +752,17 @@ static int ipoib_start_xmit(struct sk_bu
ipoib_neigh_free(dev, neigh);
spin_unlock_irqrestore(&priv->lock, flags);
ipoib_path_lookup(skb, dev);
- return NETDEV_TX_OK;
+ goto unlock;
}

if (ipoib_cm_get(neigh)) {
if (ipoib_cm_up(neigh)) {
ipoib_cm_send(dev, skb, ipoib_cm_get(neigh));
- return NETDEV_TX_OK;
+ goto unlock;
}
} else if (neigh->ah) {
ipoib_send(dev, skb, neigh->ah, IPOIB_QPN(n->ha));
- return NETDEV_TX_OK;
+ goto unlock;
}

if (skb_queue_len(&neigh->queue) < IPOIB_MAX_PATH_REC_QUEUE) {
@@ -793,13 +796,14 @@ static int ipoib_start_xmit(struct sk_bu
phdr->hwaddr + 4);
dev_kfree_skb_any(skb);
++dev->stats.tx_dropped;
- return NETDEV_TX_OK;
+ goto unlock;
}

unicast_arp_send(skb, dev, phdr);
}
}
-
+unlock:
+ rcu_read_unlock();
return NETDEV_TX_OK;
}

@@ -837,7 +841,7 @@ static int ipoib_hard_header(struct sk_b
dst = skb_dst(skb);
n = NULL;
if (dst)
- n = dst_get_neighbour(dst);
+ n = dst_get_neighbour_raw(dst);
if ((!dst || !n) && daddr) {
struct ipoib_pseudoheader *phdr =
(struct ipoib_pseudoheader *) skb_push(skb, sizeof *phdr);
--- a/drivers/infiniband/ulp/ipoib/ipoib_multicast.c
+++ b/drivers/infiniband/ulp/ipoib/ipoib_multicast.c
@@ -265,7 +265,7 @@ static int ipoib_mcast_join_finish(struc

skb->dev = dev;
if (dst)
- n = dst_get_neighbour(dst);
+ n = dst_get_neighbour_raw(dst);
if (!dst || !n) {
/* put pseudoheader back on for next time */
skb_push(skb, sizeof (struct ipoib_pseudoheader));
@@ -721,6 +721,8 @@ out:
if (mcast && mcast->ah) {
struct dst_entry *dst = skb_dst(skb);
struct neighbour *n = NULL;
+
+ rcu_read_lock();
if (dst)
n = dst_get_neighbour(dst);
if (n && !*to_ipoib_neigh(n)) {
@@ -733,7 +735,7 @@ out:
list_add_tail(&neigh->list, &mcast->neigh_list);
}
}
-
+ rcu_read_unlock();
spin_unlock_irqrestore(&priv->lock, flags);
ipoib_send(dev, skb, mcast->ah, IB_MULTICAST_QPN);
return;


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