On Fri, May 22, 2015 at 10:16:26 -0400, John Ferlan wrote:
>
>
> On 05/21/2015 06:42 PM, Jiri Denemark wrote:
> > Our usage of pthread conditions does not allow a single thread to wait
> > for several events from different sources. This is because the condition
> > is bound to the source of the event. We can invert the usage by giving
> > each thread its own condition and providing APIs for registering this
> > thread condition with several sources. Each of the sources can then
> > signal the thread condition.
> >
> > Thread queues also support several threads to be registered with a
> > single event source, which can either wakeup all waiting threads or just
> > the first one.
> >
> > Signed-off-by: Jiri Denemark <jdenemar@xxxxxxxxxx>
> > ---
> > po/POTFILES.in | 1 +
> > src/Makefile.am | 2 +
> > src/libvirt_private.syms | 15 ++
> > src/util/virthreadqueue.c | 343 ++++++++++++++++++++++++++++++++++++++++++++++
> > src/util/virthreadqueue.h | 54 ++++++++
> > 5 files changed, 415 insertions(+)
> > create mode 100644 src/util/virthreadqueue.c
> > create mode 100644 src/util/virthreadqueue.h
> >
>
> Ran the series through Coverity and came back with this gem
>
> > +
> > +void
> > +virThreadQueueFree(virThreadQueuePtr queue)
> > +{
> > + if (!queue)
> > + return;
> > +
> > + while (queue->head)
> > + virThreadQueueRemove(queue, queue->head);
>
> (3) Event cond_true: Condition "queue->head", taking true branch
> (6) Event loop_begin: Jumped back to beginning of loop
> (7) Event cond_true: Condition "queue->head", taking true branch
>
> 283 while (queue->head)
>
> (4) Event freed_arg: "virThreadQueueRemove" frees "queue->head". [details]
> (5) Event loop: Jumping back to the beginning of the loop
> (8) Event deref_arg: Calling "virThreadQueueRemove" dereferences freed pointer "queue->head". [details]
>
> 284 virThreadQueueRemove(queue, queue->head);
False positive. If virThreadQueueRemove frees queue->head, it also
updates it with queue->head->next.
Jirka
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