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Re: [PATCH 4/6] Do not call _xend if no transaction is active.
- From: Andi Kleen <andi at firstfloor dot org>
- To: libc-alpha at sourceware dot org
- Date: Mon, 02 Sep 2013 14:01:23 -0700
- Subject: Re: [PATCH 4/6] Do not call _xend if no transaction is active.
- Authentication-results: sourceware.org; auth=none
- References: <20130902075228 dot GA4792 at linux dot vnet dot ibm dot com> <20130902080450 dot GD4997 at linux dot vnet dot ibm dot com>
Dominik Vogt <vogt@linux.vnet.ibm.com> writes:
> If pthread_mutex_unlock is called without the futex locked and no transaction
> open does not necessarily mean that pthread_mutex_lock has not been called.
> The transaction may have been closed in third party code. While this _may_ be
> a bug in the software as a whole, unlock should not crash the program.
>
> Overall it is problematic to close transactions if you are not completely sure
> that you have opened the transaction yourself. I see no general solution for
> this except installing coding rules for transactional code.
The XTEST is currently 4 cycles.
Also unlocking free locks is undefined.
The plan was to wait for user feedback if that is really needed because
of the performance overhead.
Nack for now.
-Andi
--
ak@linux.intel.com -- Speaking for myself only