kern/78227: [netinet] [patch] Destroying a network interface leaks kernel memory

[Bruce M Simpson]

The following reply was made to PR kern/78227; it has been noted by GNATS.

From: Bruce M Simpson <bms at incunabulum.net>
To: freebsd-gnats-submit at FreeBSD.org
Cc:  
Subject: Re: kern/78227: [netinet] [patch] Destroying a network interface
 leaks kernel memory
Date: Wed, 27 Sep 2006 15:40:41 +0100

 To reproduce this bug on 7-CURRENT:
 
 0. Note memory usage before beginning:
 sandbox# vmstat -m | grep in_multi
          Type InUse MemUse HighUse Requests  Size(s)
      in_multi     4     1K       -        4  32
 
 1. Create a clonable interface e.g. a vlan.
 sandbox# ifconfig vlan0 create
 sandbox# ifconfig vlan0 vlan 1 vlandev ed0
 
 2. Bind it to netinet by configuring an IPv4 address.
 sandbox# ifconfig vlan0 10.0.0.1/24
 
 3. Note membership of 224.0.0.1:
 sandbox# netstat -g | grep vlan0
 224.0.0.1               01:00:5e:00:00:01       vlan0
 
 4. Note memory usage:
 sandbox# vmstat -m | grep in_multi
      in_multi     5     1K       -        5  32
 
 5. Unbind from netinet by deleting the address:
 sandbox# ifconfig vlan0 delete
 
 6. Note memory usage:
 sandbox# vmstat -m | grep in_multi
      in_multi     5     1K       -        5  32
 
 7. Note membership of 224.0.0.1:
 sandbox# netstat -g | grep vlan0
 224.0.0.1               01:00:5e:00:00:01       vlan0
 
 8. Destroy the interface instance:
 sandbox# ifconfig vlan0 destroy
 
 9. Note memory usage:
 sandbox# vmstat -m | grep in_multi
          Type InUse MemUse HighUse Requests  Size(s)
      in_multi     5     1K       -        5  32
 
 10. Try creating another vlan interface; note than InUse does not go down.