Re: [Valgrind-users] Helgrind 3.9.0: false positive with pthread_mutex_destroy

[Saurabh T <sa...@ho...>]

----------------------------------------
> From: fa...@kd...
> To: val...@li...
> CC: sa...@ho...
> Subject: Re: [Valgrind-users] Helgrind 3.9.0: false positive with pthread_mutex_destroy
> Date: Thu, 7 Nov 2013 17:25:57 +0100
>
> On Thursday 07 November 2013 16:22:56 Saurabh T wrote:
>> Helgrind seems to be reporting false positive data race when
>> pthread_mutex_destroy is called in a different thread from
>> pthread_mutex_unlock. Unfortunately I cannot make a test case, sorry. But
>> here's the relevant output:
>> <snip>
>
> Can you prove that the destroy cannot happen during the unlock?

Not without code of course, but I dont believe it can. It can however happen *before* the unlock. I believe this is allowed by the standard? The code is something like this:
Thread 1:
  locks
  deletes
  unlocks
Thread 2:
  locks
  does_stuff
  unlocks
 
saurabh

>
>> This was not a problem with 3.8.1 so appears to be a regression or new bug.
>
> ... or a fix, which detects an actual problem in the code :)
>
> --
> David Faure, fa...@kd..., http://www.davidfaure.fr
> Working on KDE, in particular KDE Frameworks 5
>