Re: futex question

From: Anirban Sinha
Date: Sun Oct 04 2009 - 12:38:25 EST


>> 1) What caused you to instrument this path in the first place? Were you
>> seeing some unexpected behavior?
>>
>> 2) I wonder why we would need to clear the robust list, but I don't see other
>> things like pi_blocked_on, etc. in execve being cleared. I'm looking into
>> this now (perhaps we don't do the same cleanup, need to check).... have to get
>> on the plane...
>
> Hmm, just setting the robust list pointer to NULL fixes the problem at
> hand, but I wonder whether we need to call exit_robust_list() as
> well.

hmm. That is an interesting thought. But I wonder if acquiring a lock and then exec()ing in the critical section is a legal thing to do. It does not feel right. Currently, with or without my change, such a thing would indefinitely block other waiters on the same futex.

Ani
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