Messages in this thread | | | Date | Wed, 31 Mar 2010 15:51:27 +0200 (CEST) | From | Thomas Gleixner <> | Subject | Re: [patch 1/5] Debugobjects transition check |
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On Wed, 31 Mar 2010, Mathieu Desnoyers wrote:
> * Thomas Gleixner (tglx@linutronix.de) wrote: > > On Mon, 29 Mar 2010, Mathieu Desnoyers wrote: > > > > > Implement a basic state machine checker in the debugobjects. > > > > Can you please add some real explanation how that checker works and > > why we want to have it ? > > We can add this to the changelog. Is it worth it to create a Documentation file > for it ?
I meant the changelog. The "Implement ...." line was not really helpful :) > > This state machine checker detects races and inconsistencies within the "active" > life of a debugobject. The checker only keeps track of the current state; all > the state machine logic is kept at the object instance level. > > The checker works by adding a supplementary "unsigned int astate" field to the > debug_obj structure. It keeps track of the current "active state" of the object. > > The only constraints that are imposed on the states by the debugobjects system > is that: > > - activation of an object sets the current active state to 0, > - deactivation of an object expects the current active state to be 0. > > For the rest of the states, the state mapping is determined by the specific > object instance. Therefore, the logic keeping track of the state machine is > within the specialized instance, without any need to know about it at the > debugobject level. > > The current object active state is changed by calling: > > debug_object_active_state(addr, descr, expect, next) > > where "expect" is the expected state and "next" is the next state to move to if > the expected state is found. A warning is generated if the expected is not > found.
Does it only warn or is there a callback to fixup things as well ?
Thanks,
tglx
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