1. 28 Nov, 2016 1 commit
    • Andrew Collins's avatar
      net: Add netdev all_adj_list refcnt propagation to fix panic · a6109221
      Andrew Collins authored
      [ Upstream commit 93409033 ]
      
      This is a respin of a patch to fix a relatively easily reproducible kernel
      panic related to the all_adj_list handling for netdevs in recent kernels.
      
      The following sequence of commands will reproduce the issue:
      
      ip link add link eth0 name eth0.100 type vlan id 100
      ip link add link eth0 name eth0.200 type vlan id 200
      ip link add name testbr type bridge
      ip link set eth0.100 master testbr
      ip link set eth0.200 master testbr
      ip link add link testbr mac0 type macvlan
      ip link delete dev testbr
      
      This creates an upper/lower tree of (excuse the poor ASCII art):
      
                  /---eth0.100-eth0
      mac0-testbr-
                  \---eth0.200-eth0
      
      When testbr is deleted, the all_adj_lists are walked, and eth0 is deleted twice from
      the mac0 list. Unfortunately, during setup in __netdev_upper_dev_link, only one
      reference to eth0 is added, so this results in a panic.
      
      This change adds reference count propagation so things are handled properly.
      
      Matthias Schiffer reported a similar crash in batman-adv:
      
      https://github.com/freifunk-gluon/gluon/issues/680
      https://www.open-mesh.org/issues/247
      
      which this patch also seems to resolve.
      
      [js] 3.12 does not have lists yet.
      Signed-off-by: default avatarAndrew Collins <acollins@cradlepoint.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      Signed-off-by: default avatarJiri Slaby <jslaby@suse.cz>
      a6109221
  2. 24 Nov, 2016 39 commits