• Du, Changbin's avatar
    debugobjects: insulate non-fixup logic related to static obj from fixup callbacks · b9fdac7f
    Du, Changbin authored
    When activating a static object we need make sure that the object is
    tracked in the object tracker.  If it is a non-static object then the
    activation is illegal.
    
    In previous implementation, each subsystem need take care of this in
    their fixup callbacks.  Actually we can put it into debugobjects core.
    Thus we can save duplicated code, and have *pure* fixup callbacks.
    
    To achieve this, a new callback "is_static_object" is introduced to let
    the type specific code decide whether a object is static or not.  If
    yes, we take it into object tracker, otherwise give warning and invoke
    fixup callback.
    
    This change has paassed debugobjects selftest, and I also do some test
    with all debugobjects supports enabled.
    
    At last, I have a concern about the fixups that can it change the object
    which is in incorrect state on fixup? Because the 'addr' may not point
    to any valid object if a non-static object is not tracked.  Then Change
    such object can overwrite someone's memory and cause unexpected
    behaviour.  For example, the timer_fixup_activate bind timer to function
    stub_timer.
    
    Link: http://lkml.kernel.org/r/1462576157-14539-1-git-send-email-changbin.du@intel.com
    [changbin.du@intel.com: improve code comments where invoke the new is_static_object callback]
      Link: http://lkml.kernel.org/r/1462777431-8171-1-git-send-email-changbin.du@intel.comSigned-off-by: default avatarDu, Changbin <changbin.du@intel.com>
    Cc: Jonathan Corbet <corbet@lwn.net>
    Cc: Josh Triplett <josh@kernel.org>
    Cc: Steven Rostedt <rostedt@goodmis.org>
    Cc: Thomas Gleixner <tglx@linutronix.de>
    Cc: Tejun Heo <tj@kernel.org>
    Cc: Christian Borntraeger <borntraeger@de.ibm.com>
    Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
    b9fdac7f
update.c 27.4 KB