I thought about this too. But, again, this doesn't actually work. And it is
very easy to pin the dead task_struct. The user can just create the
SIGEV_THREAD_ID timer and kill the sub-thread (->it_process). Without
calling timer_settime() the timer can't notice the death.
(just in case, please note that the next patch doesn't make things worse,
when ->group_leader dies the timer should be destroyed soon).
I think it is better to convert the posix timers to use "struct pid*" instead
of "struct task_struct*". This change looks more or less straightforward, and
it should fix the problem.
Oleg.
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