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authorDavid Woodhouse <dwmw2@infradead.org>2012-11-27 23:28:36 +0000
committerDavid Woodhouse <David.Woodhouse@intel.com>2012-12-02 00:05:14 +0000
commitb89588531f1db93a218c108eee713ff6002a67bf (patch)
tree074d0b433a381f95325082c8d9f0ba10a835b517 /net/atm
parentc971f08cba56ed17fe22040ca5ff97fe5c3f0bd7 (diff)
br2684: don't send frames on not-ready vcc
Avoid submitting packets to a vcc which is being closed. Things go badly wrong when the ->pop method gets later called after everything's been torn down. Use the ATM socket lock for synchronisation with vcc_destroy_socket(), which clears the ATM_VF_READY bit under the same lock. Otherwise, we could end up submitting a packet to the device driver even after its ->ops->close method has been called. And it could call the vcc's ->pop method after the protocol has been shut down. Which leads to a panic. Signed-off-by: David Woodhouse <David.Woodhouse@intel.com> Acked-by: Krzysztof Mazur <krzysiek@podlesie.net>
Diffstat (limited to 'net/atm')
-rw-r--r--net/atm/br2684.c43
1 files changed, 40 insertions, 3 deletions
diff --git a/net/atm/br2684.c b/net/atm/br2684.c
index 8eb6fbe8d8dd..4de3ae7bc3e2 100644
--- a/net/atm/br2684.c
+++ b/net/atm/br2684.c
@@ -68,6 +68,7 @@ struct br2684_vcc {
/* keep old push, pop functions for chaining */
void (*old_push)(struct atm_vcc *vcc, struct sk_buff *skb);
void (*old_pop)(struct atm_vcc *vcc, struct sk_buff *skb);
+ void (*old_release_cb)(struct atm_vcc *vcc);
enum br2684_encaps encaps;
struct list_head brvccs;
#ifdef CONFIG_ATM_BR2684_IPFILTER
@@ -269,6 +270,17 @@ static int br2684_xmit_vcc(struct sk_buff *skb, struct net_device *dev,
return !atmvcc->send(atmvcc, skb);
}
+static void br2684_release_cb(struct atm_vcc *atmvcc)
+{
+ struct br2684_vcc *brvcc = BR2684_VCC(atmvcc);
+
+ if (atomic_read(&brvcc->qspace) > 0)
+ netif_wake_queue(brvcc->device);
+
+ if (brvcc->old_release_cb)
+ brvcc->old_release_cb(atmvcc);
+}
+
static inline struct br2684_vcc *pick_outgoing_vcc(const struct sk_buff *skb,
const struct br2684_dev *brdev)
{
@@ -280,6 +292,8 @@ static netdev_tx_t br2684_start_xmit(struct sk_buff *skb,
{
struct br2684_dev *brdev = BRPRIV(dev);
struct br2684_vcc *brvcc;
+ struct atm_vcc *atmvcc;
+ netdev_tx_t ret = NETDEV_TX_OK;
pr_debug("skb_dst(skb)=%p\n", skb_dst(skb));
read_lock(&devs_lock);
@@ -290,9 +304,26 @@ static netdev_tx_t br2684_start_xmit(struct sk_buff *skb,
dev->stats.tx_carrier_errors++;
/* netif_stop_queue(dev); */
dev_kfree_skb(skb);
- read_unlock(&devs_lock);
- return NETDEV_TX_OK;
+ goto out_devs;
}
+ atmvcc = brvcc->atmvcc;
+
+ bh_lock_sock(sk_atm(atmvcc));
+
+ if (test_bit(ATM_VF_RELEASED, &atmvcc->flags) ||
+ test_bit(ATM_VF_CLOSE, &atmvcc->flags) ||
+ !test_bit(ATM_VF_READY, &atmvcc->flags)) {
+ dev->stats.tx_dropped++;
+ dev_kfree_skb(skb);
+ goto out;
+ }
+
+ if (sock_owned_by_user(sk_atm(atmvcc))) {
+ netif_stop_queue(brvcc->device);
+ ret = NETDEV_TX_BUSY;
+ goto out;
+ }
+
if (!br2684_xmit_vcc(skb, dev, brvcc)) {
/*
* We should probably use netif_*_queue() here, but that
@@ -304,8 +335,11 @@ static netdev_tx_t br2684_start_xmit(struct sk_buff *skb,
dev->stats.tx_errors++;
dev->stats.tx_fifo_errors++;
}
+ out:
+ bh_unlock_sock(sk_atm(atmvcc));
+ out_devs:
read_unlock(&devs_lock);
- return NETDEV_TX_OK;
+ return ret;
}
/*
@@ -378,6 +412,7 @@ static void br2684_close_vcc(struct br2684_vcc *brvcc)
list_del(&brvcc->brvccs);
write_unlock_irq(&devs_lock);
brvcc->atmvcc->user_back = NULL; /* what about vcc->recvq ??? */
+ brvcc->atmvcc->release_cb = brvcc->old_release_cb;
brvcc->old_push(brvcc->atmvcc, NULL); /* pass on the bad news */
kfree(brvcc);
module_put(THIS_MODULE);
@@ -554,9 +589,11 @@ static int br2684_regvcc(struct atm_vcc *atmvcc, void __user * arg)
brvcc->encaps = (enum br2684_encaps)be.encaps;
brvcc->old_push = atmvcc->push;
brvcc->old_pop = atmvcc->pop;
+ brvcc->old_release_cb = atmvcc->release_cb;
barrier();
atmvcc->push = br2684_push;
atmvcc->pop = br2684_pop;
+ atmvcc->release_cb = br2684_release_cb;
/* initialize netdev carrier state */
if (atmvcc->dev->signal == ATM_PHY_SIG_LOST)

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