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authorStephen Hemminger <shemminger@vyatta.com>2008-09-08 13:44:40 -0700
committerDavid S. Miller <davem@davemloft.net>2008-09-08 13:46:54 -0700
commit8d4698f7a54a492a1b96c505b30fe750ae3e61d5 (patch)
tree4bec6c7dcf06bb5df9645d702d554a071007b83a /net/bridge/br_ioctl.c
parentd315492b1a6ba29da0fa2860759505ae1b2db857 (diff)
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.c8
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))