From 8d4698f7a54a492a1b96c505b30fe750ae3e61d5 Mon Sep 17 00:00:00 2001 From: Stephen Hemminger Date: Mon, 8 Sep 2008 13:44:40 -0700 Subject: 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 Signed-off-by: David S. Miller --- net/bridge/br_ioctl.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) (limited to 'net/bridge/br_ioctl.c') diff --git a/net/bridge/br_ioctl.c b/net/bridge/br_ioctl.c index eeee218..5bbf073 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)) -- cgit v1.1