On 19-Dec-01 Alfred Perlstein wrote:
> * Julian Elischer <[EMAIL PROTECTED]> [011218 18:20] wrote:
>> now, what is to say that the process has not exitted by this stage, and
>> been reeped by init (on SMP)
>> particularly since between the two is:
>>         /*
>>          * Preserve synchronization semantics of vfork.  If waiting for
>>          * child to exec or exit, set P_PPWAIT on child, and sleep on our
>>          * proc (in case of exit).
>>          */
>>         PROC_LOCK(p2);
>>         while (p2->p_flag & P_PPWAIT)
>>                 msleep(p1, &p2->p_mtx, PWAIT, "ppwait", 0);
>>         PROC_UNLOCK(p2);
>> It may be that due to some semantics of teh fork calls
>> you cannot have P_PPWAIT and a process queued to run on the other
>> processor while reparented to init(1) but I can't see it..
>> the result would be that the return value MIGHT be teh pid
>> of a totally different process if the proc structure had been re-used.
>> Alternatively I could have some good weed here...
> That's not possible, since the parent is waiting the kernel will
> not reparent unless the parent exits, which it doesn't because it's
> waiting for the child.
> You owe the Oracle a large bong rip.

Look at RFNOWAIT silly.  It forces a parent to init during fork1() itself.


John Baldwin <[EMAIL PROTECTED]>  <><  http://www.FreeBSD.org/~jhb/
"Power Users Use the Power to Serve!"  -  http://www.FreeBSD.org/

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