diff options
| author | Stephen Hemminger <shemminger@vyatta.com> | 2008-09-08 13:44:40 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2008-09-08 13:46:54 -0700 |
| commit | 8d4698f7a54a492a1b96c505b30fe750ae3e61d5 (patch) | |
| tree | 4bec6c7dcf06bb5df9645d702d554a071007b83a /net/bridge/br_ioctl.c | |
| parent | d315492b1a6ba29da0fa2860759505ae1b2db857 (diff) | |
| download | lwn-8d4698f7a54a492a1b96c505b30fe750ae3e61d5.tar.gz lwn-8d4698f7a54a492a1b96c505b30fe750ae3e61d5.zip | |
bridge: don't allow setting hello time to zero
Dushan Tcholich reports that on his system ksoftirqd can consume
between %6 to %10 of cpu time, and cause ~200 context switches per
second.
He then correlated this with a report by bdupree@techfinesse.com:
http://marc.info/?l=linux-kernel&m=119613299024398&w=2
and the culprit cause seems to be starting the bridge interface.
In particular, when starting the bridge interface, his scripts
are specifying a hello timer interval of "0".
The bridge hello time can't be safely set to values less than 1
second, otherwise it is possible to end up with a runaway timer.
Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/bridge/br_ioctl.c')
| -rw-r--r-- | net/bridge/br_ioctl.c | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/net/bridge/br_ioctl.c b/net/bridge/br_ioctl.c index eeee218eed80..5bbf07362172 100644 --- a/net/bridge/br_ioctl.c +++ b/net/bridge/br_ioctl.c @@ -188,15 +188,21 @@ static int old_dev_ioctl(struct net_device *dev, struct ifreq *rq, int cmd) return 0; case BRCTL_SET_BRIDGE_HELLO_TIME: + { + unsigned long t = clock_t_to_jiffies(args[1]); if (!capable(CAP_NET_ADMIN)) return -EPERM; + if (t < HZ) + return -EINVAL; + spin_lock_bh(&br->lock); - br->bridge_hello_time = clock_t_to_jiffies(args[1]); + br->bridge_hello_time = t; if (br_is_root_bridge(br)) br->hello_time = br->bridge_hello_time; spin_unlock_bh(&br->lock); return 0; + } case BRCTL_SET_BRIDGE_MAX_AGE: if (!capable(CAP_NET_ADMIN)) |