• Mathieu Poirier's avatar
    coresight: removing bind/unbind options from sysfs · b15f0fb6
    Mathieu Poirier authored
    The coresight drivers have absolutely no control over bind and unbind
    operations triggered from sysfs. The operations simply can't be
    cancelled or denied event when one or several tracing sessions are
    under way.  Since the memory associated to individual device is
    invariably freed, the end result is a kernel crash when the path from
    source to sink is travelled again as demonstrated here[1].
    
    One solution could be to keep track of all the path (i.e tracing
    session) that get created and iterate through the elements of those path
    looking for the coresight device that is being removed.  This proposition
    doesn't scale well since there is no upper bound on the amount of
    concurrent trace session that can be created.
    
    With the above in mind, this patch prevent devices from being unbounded
    from their driver by using the driver->suppress_bind_attr option.  That way
    trace sessions can be managed without fearing to loose devices.
    
    Since device can't be removed anymore the xyz_remove() functions found in
    each driver is also removed.
    
    [1]. http://www.spinics.net/lists/arm-kernel/msg474952.htmlReported-by: default avatarRabin Vincent <rabin@rab.in>
    Signed-off-by: default avatarMathieu Poirier <mathieu.poirier@linaro.org>
    Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
    b15f0fb6
coresight-etb10.c 13.7 KB