Re: [patch 2.6.9] Avoid a rare deadlock during unwind

From: Keith Owens <>
Date: 2004-10-22 20:10:08
On Fri, 22 Oct 2004 02:27:30 -0700, 
David Mosberger <> wrote:
>>>>>> On Fri, 22 Oct 2004 00:44:35 +1000, Keith Owens <> said:
>  Keith> o if both the unw.lock spinlock and a script's read-write lock must be
>  Keith> acquired using a method that might sleep, then the read-write lock
>  Keith> must be acquired first.
>  Keith> adding "using a method that might sleep".  The only read-write lock
>  Keith> code under spinlock(unw.lock) is write_trylock(), which never sleeps.
>  Keith> If you agree with this analysis, then I am happy to update the comment.
>No, the comment was intending to establish the lock hierarchy.  If there
>are no other paths where the locks are acquire in the other order, then
>it's OK.  I'd just reverse the comment to match the (new) reality.

Reversing the comment would also be wrong.  You are not allowed to
sleep while holding a spinlock.

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Received on Fri Oct 22 06:11:40 2004

This archive was generated by hypermail 2.1.8 : 2005-08-02 09:20:31 EST