From 8d4698f7a54a492a1b96c505b30fe750ae3e61d5 Mon Sep 17 00:00:00 2001 From: Stephen Hemminger Date: Mon, 8 Sep 2008 13:44:40 -0700 Subject: [PATCH] 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 +++++++- net/bridge/br_sysfs_br.c | 26 ++++++++++++++++++-------- 2 files changed, 25 insertions(+), 9 deletions(-) diff --git a/net/bridge/br_ioctl.c b/net/bridge/br_ioctl.c index eeee218eed8..5bbf0736217 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)) diff --git a/net/bridge/br_sysfs_br.c b/net/bridge/br_sysfs_br.c index 27d6a511c8c..158dee8b496 100644 --- a/net/bridge/br_sysfs_br.c +++ b/net/bridge/br_sysfs_br.c @@ -29,11 +29,12 @@ */ static ssize_t store_bridge_parm(struct device *d, const char *buf, size_t len, - void (*set)(struct net_bridge *, unsigned long)) + int (*set)(struct net_bridge *, unsigned long)) { struct net_bridge *br = to_bridge(d); char *endp; unsigned long val; + int err; if (!capable(CAP_NET_ADMIN)) return -EPERM; @@ -43,9 +44,9 @@ static ssize_t store_bridge_parm(struct device *d, return -EINVAL; spin_lock_bh(&br->lock); - (*set)(br, val); + err = (*set)(br, val); spin_unlock_bh(&br->lock); - return len; + return err ? err : len; } @@ -56,12 +57,13 @@ static ssize_t show_forward_delay(struct device *d, return sprintf(buf, "%lu\n", jiffies_to_clock_t(br->forward_delay)); } -static void set_forward_delay(struct net_bridge *br, unsigned long val) +static int set_forward_delay(struct net_bridge *br, unsigned long val) { unsigned long delay = clock_t_to_jiffies(val); br->forward_delay = delay; if (br_is_root_bridge(br)) br->bridge_forward_delay = delay; + return 0; } static ssize_t store_forward_delay(struct device *d, @@ -80,12 +82,17 @@ static ssize_t show_hello_time(struct device *d, struct device_attribute *attr, jiffies_to_clock_t(to_bridge(d)->hello_time)); } -static void set_hello_time(struct net_bridge *br, unsigned long val) +static int set_hello_time(struct net_bridge *br, unsigned long val) { unsigned long t = clock_t_to_jiffies(val); + + if (t < HZ) + return -EINVAL; + br->hello_time = t; if (br_is_root_bridge(br)) br->bridge_hello_time = t; + return 0; } static ssize_t store_hello_time(struct device *d, @@ -104,12 +111,13 @@ static ssize_t show_max_age(struct device *d, struct device_attribute *attr, jiffies_to_clock_t(to_bridge(d)->max_age)); } -static void set_max_age(struct net_bridge *br, unsigned long val) +static int set_max_age(struct net_bridge *br, unsigned long val) { unsigned long t = clock_t_to_jiffies(val); br->max_age = t; if (br_is_root_bridge(br)) br->bridge_max_age = t; + return 0; } static ssize_t store_max_age(struct device *d, struct device_attribute *attr, @@ -126,9 +134,10 @@ static ssize_t show_ageing_time(struct device *d, return sprintf(buf, "%lu\n", jiffies_to_clock_t(br->ageing_time)); } -static void set_ageing_time(struct net_bridge *br, unsigned long val) +static int set_ageing_time(struct net_bridge *br, unsigned long val) { br->ageing_time = clock_t_to_jiffies(val); + return 0; } static ssize_t store_ageing_time(struct device *d, @@ -180,9 +189,10 @@ static ssize_t show_priority(struct device *d, struct device_attribute *attr, (br->bridge_id.prio[0] << 8) | br->bridge_id.prio[1]); } -static void set_priority(struct net_bridge *br, unsigned long val) +static int set_priority(struct net_bridge *br, unsigned long val) { br_stp_set_bridge_priority(br, (u16) val); + return 0; } static ssize_t store_priority(struct device *d, struct device_attribute *attr, -- 2.41.0