• Cong Wang's avatar
    netpoll: fix a rtnl lock assertion failure · f92d3180
    Cong Wang authored
    v4: hold rtnl lock for the whole netpoll_setup()
    v3: remove the comment
    v2: use RCU read lock
    
    This patch fixes the following warning:
    
    [   72.013864] RTNL: assertion failed at net/core/dev.c (4955)
    [   72.017758] Pid: 668, comm: netpoll-prep-v6 Not tainted 3.8.0-rc1+ #474
    [   72.019582] Call Trace:
    [   72.020295]  [<ffffffff8176653d>] netdev_master_upper_dev_get+0x35/0x58
    [   72.022545]  [<ffffffff81784edd>] netpoll_setup+0x61/0x340
    [   72.024846]  [<ffffffff815d837e>] store_enabled+0x82/0xc3
    [   72.027466]  [<ffffffff815d7e51>] netconsole_target_attr_store+0x35/0x37
    [   72.029348]  [<ffffffff811c3479>] configfs_write_file+0xe2/0x10c
    [   72.030959]  [<ffffffff8115d239>] vfs_write+0xaf/0xf6
    [   72.032359]  [<ffffffff81978a05>] ? sysret_check+0x22/0x5d
    [   72.033824]  [<ffffffff8115d453>] sys_write+0x5c/0x84
    [   72.035328]  [<ffffffff819789d9>] system_call_fastpath+0x16/0x1b
    
    In case of other races, hold rtnl lock for the entire netpoll_setup() function.
    
    Cc: Eric Dumazet <eric.dumazet@gmail.com>
    Cc: Jiri Pirko <jiri@resnulli.us>
    Cc: David S. Miller <davem@davemloft.net>
    Signed-off-by: default avatarCong Wang <amwang@redhat.com>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    f92d3180
netpoll.c 29.3 KB