pthread_key_delete issue

pthread_key_delete issue

[Stephane Clairet]

Hi,
after migrating from 2.8.0 version to 2.9.1 version, I have an issue with pthread_key_delete function.
Sometimes, the application on which I work freezes after calling pthread_key_delete.

In fact, the app is stopped on this line: ptw32_mcs_lock_release (&keyLock) (line 106 into pthread_key_delete.c file)
It seems to be reproduced only when the specific data key concerns several threads.
The explanation is maybe inside the pthread_key_delete implementation:

int pthread_key_delete (pthread_key_t key)
{
    ptw32_mcs_lock_acquire (&(key->keyLock), &keyLock);
    ...
    while ((assoc = (ThreadKeyAssoc *) key->threads) != NULL)
    {
        ...
        ptw32_mcs_lock_release (&keyLock);
    }
}

The freeze always occurs when the program try to release the key lock a second time. I don't know if it's supposed to be supported.
Release the key lock outside the while loop seems to fix the issue.

Thanks for help.
Regards.

Stéphane




Stephane Clairet
Architecte Logiciel

4D SAS
60, rue d'Alsace
92110 Clichy
France

Standard : +33 1 40 87 92 00
Email :    Stephane.Clairet@4d.com
Web :      www.4D.com

Re: pthread_key_delete issue

[Ross Johnson]

Hi Stéphane,

Thank you for reporting and fixing this. The error was indeed introduced 
after 2.8.0, i.e. when I changed to use MCS locks in this part of the code.

There will be a new test also for this to make sure it doesn't regress 
again.

I will update the CVS repository on sourceware.org soon and a little 
earlier to the Git repository at:

http://sourceforge.net/projects/pthreads4w/

Regards.
Ross

On 24/10/2012 12:29 AM, Stephane Clairet wrote:
> Hi,
> after migrating from 2.8.0 version to 2.9.1 version, I have an issue with pthread_key_delete function.
> Sometimes, the application on which I work freezes after calling pthread_key_delete.
>
> In fact, the app is stopped on this line: ptw32_mcs_lock_release (&keyLock) (line 106 into pthread_key_delete.c file)
> It seems to be reproduced only when the specific data key concerns several threads.
> The explanation is maybe inside the pthread_key_delete implementation:
>
> int pthread_key_delete (pthread_key_t key)
> {
>      ptw32_mcs_lock_acquire (&(key->keyLock), &keyLock);
>      ...
>      while ((assoc = (ThreadKeyAssoc *) key->threads) != NULL)
>      {
>          ...
>          ptw32_mcs_lock_release (&keyLock);
>      }
> }
>
> The freeze always occurs when the program try to release the key lock a second time. I don't know if it's supposed to be supported.
> Release the key lock outside the while loop seems to fix the issue.
>
> Thanks for help.
> Regards.
>
> Stéphane
>
>
>
>
> Stephane Clairet
> Architecte Logiciel
>
> 4D SAS
> 60, rue d'Alsace
> 92110 Clichy
> France
>
> Standard : +33 1 40 87 92 00
> Email :    Stephane.Clairet@4d.com
> Web :      www.4D.com
>
>