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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>
This commit is contained in:
David Woodhouse 2012-11-27 23:28:36 +00:00 committed by David Woodhouse
parent c971f08cba
commit b89588531f
1 changed files with 40 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

43
net/atm/br2684.c
View File

@ -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)