Re: [Xenomai-core] [PATCH] Flush xnfree backlog after thread deletion in root context

[Philippe Gerum <rpm@xenomai.org>]

Gilles Chanteperdrix wrote:
> On Tue, May 13, 2008 at 11:10 AM, Jan Kiszka <jan.kiszka@domain.hid> wrote:
>> Gilles Chanteperdrix wrote:
>>  > On Tue, May 13, 2008 at 10:26 AM, Jan Kiszka <jan.kiszka@domain.hid> wrote:
>>  >>  @@ -1236,6 +1236,9 @@ void xnpod_delete_thread(xnthread_t *thr
>>  >>                 xnthread_cleanup_tcb(thread);
>>  >>
>>  >>                 xnarch_finalize_no_switch(xnthread_archtcb(thread));
>>  >>  +
>>  >>  +               if (xnthread_test_state(sched->runthread, XNROOT))
>>  >>  +                       xnfreesync();
>>  >>         }
>>  >
>>  > No, this does not look good. The point of deferring TCB freeing is
>>  > that the TCB will be accessed shortly after it is freed.
>>
>>  By whom in this case? The thread was not active anymore. IIRC, the
>>  use-after-release issue was related to self-deletions.
> 
> I do not remember the issue precisely, I know that it was related to
> thread deletion hooks.

The point is that we have to run thread deletion hooks on behalf of the outgoing
thread context; this is a strong requirement.

 The XNARCH_WANT_UNLOCKED_CTXSW complicated the
> issue further.
> 


-- 
Philippe.