Possible locking issue in viotape.c

From: Kevin Winchester
Date: Thu Dec 06 2007 - 20:30:23 EST


Daniel Walker wrote:
>
> I've posted all the ones I've done so far ..
>
> ftp://source.mvista.com/pub/dwalker/sem2mutex-2.6.24-rc4/
>
> Feel free to review or test them.. I've found it pretty easy to simply
> grep for certain class of semaphore usage, check if it's conforming to
> the mutex requirements, then convert it or not.. Checking them is
> getting to be a habit, so I don't think a list would help me.. However,
> someone else might be able to use it..
>

Thanks, that helps me not duplicate anything. One of the first ones I
was looking at (before your post) was viotape.c, which is in your patch
set. However, looking at the uses of the semaphore, I see that on line
409-410 the following code:

if (noblock)
return count;

which seems to ignore the fact that the semaphore has been downed (not
to mention the dma buffer and op struct allocations. I think it should be:

if (noblock)
ret = count;
goto free_dma;

instead. Do you want to make sure I'm right about that and fold it into
your patch? Or have you already submitted your patch (or should it be
in a separate patch? Alternatively, I can submit the patch if you don't
want to bother with it.

--
Kevin Winchester
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