• Roman Mashak's avatar
    net sched actions: decrement module reference count after table flush. · a1d473c0
    Roman Mashak authored
    commit edb9d1bf upstream.
    
    When tc actions are loaded as a module and no actions have been installed,
    flushing them would result in actions removed from the memory, but modules
    reference count not being decremented, so that the modules would not be
    unloaded.
    
    Following is example with GACT action:
    
    % sudo modprobe act_gact
    % lsmod
    Module                  Size  Used by
    act_gact               16384  0
    %
    % sudo tc actions ls action gact
    %
    % sudo tc actions flush action gact
    % lsmod
    Module                  Size  Used by
    act_gact               16384  1
    % sudo tc actions flush action gact
    % lsmod
    Module                  Size  Used by
    act_gact               16384  2
    % sudo rmmod act_gact
    rmmod: ERROR: Module act_gact is in use
    ....
    
    After the fix:
    % lsmod
    Module                  Size  Used by
    act_gact               16384  0
    %
    % sudo tc actions add action pass index 1
    % sudo tc actions add action pass index 2
    % sudo tc actions add action pass index 3
    % lsmod
    Module                  Size  Used by
    act_gact               16384  3
    %
    % sudo tc actions flush action gact
    % lsmod
    Module                  Size  Used by
    act_gact               16384  0
    %
    % sudo tc actions flush action gact
    % lsmod
    Module                  Size  Used by
    act_gact               16384  0
    % sudo rmmod act_gact
    % lsmod
    Module                  Size  Used by
    %
    
    Fixes: f97017cd ("net-sched: Fix actions flushing")
    Signed-off-by: default avatarRoman Mashak <mrv@mojatatu.com>
    Signed-off-by: default avatarJamal Hadi Salim <jhs@mojatatu.com>
    Acked-by: default avatarCong Wang <xiyou.wangcong@gmail.com>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    [bwh: Backported to 3.2: adjust context]
    Signed-off-by: default avatarBen Hutchings <ben@decadent.org.uk>
    a1d473c0
act_api.c 23.4 KB