[okl4-developer] KD# exception delivery error

[Carl van Schaik]

This exception handler/scheduler hack is fixed in later versions, but
I'm not sure whats in the release you are working on. The main reason it
was in using the exception handler previously was due a security
concern. In the old API, a thread was able to changes its exception
handler thread without asking a manager thread. Thus it could use this
to send IPCs to any thread in the system since the kernel assumes the
exception handler is the correct thread and thus does not need security
checks.

--
Carl

Geoffrey Lee wrote:
> On Mon, Jul 30, 2007 at 01:02:43PM -0400, Jorge Torres wrote:
>   
>> Than you very much Geoffrey,
>>
>>     
>
> Hi Jorge
>
>
>   
>> I will try to find where such hack is, but at this moment I can't understand
>> something: when you mean a hack that uses the scheduler for exceptions, you
>> mean that scheduler thread is responsible for its corresponding thread
>> exemptions?, shouldn't it be thread's handler thread?
>>
>>     
>
> When you receive an exception, it should check to see if there is
> an exception handler registered and if so use that to fake an IPC
> to the exception handler.
>
> However, due to the hack being there, it uses the registered
> scheduler handler instead.
>
> You are correct, it should use the exception handler not
> the scheduler to send the exception IPCs. 
>
> The send_exception_ipc() function is architecture specific, IA-32 seems
> to use the scheduler (which is probably wrong) while ARM does the right
> thing.
>
>
>
>   
>> Thank you very much, and please forgive my ignorance,
>>
>> Jorge
>>
>>     
>
> 	- gl
>
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