Re: Threads and race conditions in slapd

["Kurt D. Zeilenga" <Kurt@OpenLDAP.org>]

The thread pool fix has been committed to HEAD.
Additionally, new BDB locking code has been committed.
Please test.

Kurt

At 04:59 AM 2002-05-27, Simon Wilkinson wrote:
>I'm trying to track down a strange, intermittent, bug with the CVS head (and 
>beta1). The symptoms are that slapd crashes having produced a number of 
>"bind: ber_scanf failed" errors. 
>
>Further investigation seems to suggest that connection_operation is being 
>called multiple times for the same operation. Things which hint at this are 
>the fact that the c->ops queue is empty (its the attempt to remove the 
>operation from the queue that causes the crash), and that c_n_ops_executing 
>is a negative number. The problem seems to only arise when the server is 
>under a reasonably heavy load. We're running on a Linux SMP system - if that 
>makes any difference.
>
>I've found one possible problem with the thread pool (additions to the free 
>list weren't protected by a mutex - ITS#1839) but am unsure how this could 
>cause the problem I'm seeing, and I'm even more unsure about where else to 
>look. Has anyone else seen this, or have any thoughts on the best line of 
>attack?
>
>Cheers,
>
>Simon.
>-- 
>Simon Wilkinson            <simon@sxw.org.uk>          http://www.sxw.org.uk
>"I assure you the thought never even crossed my mind, lord."
>"Indeed?  Then if I were you I'd sue my face for slander."
> - Terry Pratchett, "The Colour of Magic"