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

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

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> Subject: Re: [Valgrind-users] Helgrind 3.9.0: false positive with pthread_mutex_destroy
> From: phi...@sk...
> To: sa...@ho...
> CC: val...@li...
> Date: Fri, 8 Nov 2013 22:46:28 +0100
>
> I think this is a regression in 3.9.0 caused by revision 13642 which:
> Fix #323432: When calling pthread_cond_destroy or pthread_mutex_destroy
> with initializers as argument Helgrind (incorrectly) reports errors.
>
> The problem is that the pthread_mutex_destroy wrapper function is
> comparing the mutex with PTHREAD_MUTEX_INITIALIZER to detect if mutex
> was initialised using PTHREAD_MUTEX_INITIALIZER
> rather than with pthread_mutex_init.

Philippe,

Thank you for the patch, it worked.
For what it's worth, the situation that you mention cannot happen for my code.

saurabh


> Now, is this really a regression ? It might in fact be a feature :).
>
> If there is no synchronisation mechanism between a thread doing
> lock/unlock and another thread calling pthread_mutex_destroy, then
> if the thread doing lock/unlock is slow, the mutex could be destroyed
> while it is locked (or even before the locking thread has started to
> lock it. And then the locking thread might try to lock a destroyed
> mutex.
>
> Philippe
>
>