diff options
| author | Eric Dumazet <eric.dumazet@gmail.com> | 2010-09-29 13:23:09 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2010-11-22 11:00:15 -0800 |
| commit | 3f266b04185de51d8e6446eb1fccec3b5e7ce575 (patch) | |
| tree | acc454774ea7b0a3647b0ac40e9778da075e15da | |
| parent | a3c1c5704f66741f3249926b31cc4a201b1faeda (diff) | |
net: add a recursion limit in xmit path
[ Upstream commits 745e20f1b626b1be4b100af5d4bf7b3439392f8f and
11a766ce915fc9f8663714eac6d59239388534ea ]
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| -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 95cc48618043..ca47a64929ff 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -2110,6 +2110,9 @@ static inline int skb_needs_linearize(struct sk_buff *skb, illegal_highdma(dev, skb))); } +static DEFINE_PER_CPU(int, xmit_recursion); +#define RECURSION_LIMIT 10 + /** * dev_queue_xmit - transmit a buffer * @skb: buffer to transmit @@ -2194,10 +2197,15 @@ gso: 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; @@ -2209,7 +2217,9 @@ gso: "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); |