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| author | Eric Dumazet <eric.dumazet@gmail.com> | 2010-09-29 13:23:09 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2010-09-29 13:23:09 -0700 |
| commit | 745e20f1b626b1be4b100af5d4bf7b3439392f8f (patch) | |
| tree | 5067e0179167106856217f7c4ddc68b15ec93db8 /net/core | |
| parent | ab79ad14a2d51e95f0ac3cef7cd116a57089ba82 (diff) | |
| download | linux-745e20f1b626b1be4b100af5d4bf7b3439392f8f.tar.gz linux-745e20f1b626b1be4b100af5d4bf7b3439392f8f.tar.bz2 linux-745e20f1b626b1be4b100af5d4bf7b3439392f8f.zip | |
net: add a recursion limit in xmit path
As tunnel devices are going to be lockless, we need to make sure a
misconfigured machine wont enter an infinite loop.
Add a percpu variable, and limit to three the number of stacked xmits.
Reported-by: Jesse Gross <jesse@nicira.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core')
| -rw-r--r-- | net/core/dev.c | 12 |
1 files changed, 11 insertions, 1 deletions
diff --git a/net/core/dev.c b/net/core/dev.c index 48ad47f402ad..50daccad6a53 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -2177,6 +2177,9 @@ static inline int __dev_xmit_skb(struct sk_buff *skb, struct Qdisc *q, return rc; } +static DEFINE_PER_CPU(int, xmit_recursion); +#define RECURSION_LIMIT 3 + /** * dev_queue_xmit - transmit a buffer * @skb: buffer to transmit @@ -2242,10 +2245,15 @@ int dev_queue_xmit(struct sk_buff *skb) if (txq->xmit_lock_owner != cpu) { + if (__this_cpu_read(xmit_recursion) > RECURSION_LIMIT) + goto recursion_alert; + HARD_TX_LOCK(dev, txq, cpu); if (!netif_tx_queue_stopped(txq)) { + __this_cpu_inc(xmit_recursion); rc = dev_hard_start_xmit(skb, dev, txq); + __this_cpu_dec(xmit_recursion); if (dev_xmit_complete(rc)) { HARD_TX_UNLOCK(dev, txq); goto out; @@ -2257,7 +2265,9 @@ int dev_queue_xmit(struct sk_buff *skb) "queue packet!\n", dev->name); } else { /* Recursion is detected! It is possible, - * unfortunately */ + * unfortunately + */ +recursion_alert: if (net_ratelimit()) printk(KERN_CRIT "Dead loop on virtual device " "%s, fix it urgently!\n", dev->name); |