On Thu, Apr 27, 2017 at 9:57 AM, Ben Pfaff <b...@ovn.org> wrote:
> On Thu, Apr 27, 2017 at 04:02:10AM -0700, William Tu wrote:
>> Before the patch, when users create bridge named "default", although
>> ovs-vsctl fails but vswitchd in the background will keep retrying it,
>> causing the systemd-udev to reach 100% cpu utilization. The reason is
>> due to frequent calls into kernel's register_netdevice function,
>> which will invoke several kernel elements who has registered on the
>> netdevice notifier chain. One of the notifier, the inetdev_event rejects
>> this devname and register_netdevice fails. The patch prohibits creating
>> "default" bridge name.
>>
>> VMWare-BZ: #1842388
>> Signed-off-by: William Tu <u9012...@gmail.com>
>
> It all seems very arbitrary. Do we understand why this is an invalid
> device name?
Yes, when kernel is configured with CONFIG_SYSCTL, creating a new
netdev creates a dir in /proc/sys/net/ipv4/conf/<device name>
The <device name> "default" and "all" is pre-existed when SYSCTL
starts (which means we should also prohibit "all") for default
property of the system's netdev. So sysctl prevents creating dev->name
is "default" or "all". A call stack is below if interested:
sysctl_dev_name_is_allowed
devinet_sysctl_register
inetdev_event
notifier_call_chain
raw_notifier_call_chain
call_netdevice_notifiers_info
register_netdevice
Regards,
William
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