On Wed, 2016-03-16 at 10:41 -0500, Jonathon Jongsma wrote:
> So, after adding the g_task_return_boolean back to _open_device_async_cb(), I
> noticed that since g_task_return_error() can potentially complete the task
> immediately (rather than in an idle handler done previously), we may be
> executing the GAsyncReadyCallback while the channel is locked. Currently, I
> don't think this causes any problems, but if the callback did anything that
> required locking the channel's mutex, that could result in a deadlock. So
> here's
> an additional proposed patch to unlock before completing the task. If this
> change is ACKed, I'd probably squash it into this patch.
>
> ------------
> diff --git a/src/channel-usbredir.c b/src/channel-usbredir.c
> index cd2ff4f..aa8e943 100644
> --- a/src/channel-usbredir.c
> +++ b/src/channel-usbredir.c
> @@ -367,17 +367,19 @@ _open_device_async_cb(GTask *task,
>
> spice_usbredir_channel_lock(channel);
>
> - if (!spice_usbredir_channel_open_device(channel, &err)) {
> + spice_usbredir_channel_open_device(channel, &err);
> + libusb_unref_device(priv->device);
> + priv->device = NULL;
> + g_boxed_free(spice_usb_device_get_type(), priv->spice_device);
> + priv->spice_device = NULL;
> +
> + spice_usbredir_channel_unlock(channel);
> +
> + if (err) {
> g_task_return_error(task, err);
> - libusb_unref_device(priv->device);
> - priv->device = NULL;
> - g_boxed_free(spice_usb_device_get_type(), priv->spice_device);
> - priv->spice_device = NULL;
> } else {
> g_task_return_boolean(task, TRUE);
> }
> -
> - spice_usbredir_channel_unlock(channel);
> }
> #endif
>
... And Fabiano pointed out that this patch is incorrect since it frees the
device even if it was successfully redirected. That's clearly wrong. New patch
coming.
>
>
> On Wed, 2016-03-16 at 10:16 -0500, Jonathon Jongsma wrote:
> > On Wed, 2016-03-16 at 11:27 +0100, Christophe Fergeau wrote:
> > > Hey,
> > >
> > > On Tue, Mar 15, 2016 at 02:31:03PM -0500, Jonathon Jongsma wrote:
> > > > +#ifndef USE_POLKIT
> > > > +static void
> > > > +_open_device_async_cb(GTask *task,
> > > > + gpointer object,
> > > > + gpointer task_data,
> > > > + GCancellable *cancellable)
> > > > +{
> > > > + GError *err = NULL;
> > > > + SpiceUsbredirChannel *channel = SPICE_USBREDIR_CHANNEL(object);
> > > > + SpiceUsbredirChannelPrivate *priv = channel->priv;
> > > > +
> > > > + spice_usbredir_channel_lock(channel);
> > > > +
> > > > + if (!spice_usbredir_channel_open_device(channel, &err)) {
> > > > + g_task_return_error(task, err);
> > > > + libusb_unref_device(priv->device);
> > > > + priv->device = NULL;
> > > > + g_boxed_free(spice_usb_device_get_type(), priv->spice_device);
> > > > + priv->spice_device = NULL;
> > > > + }
> > > > +
> > > > + spice_usbredir_channel_unlock(channel);
> > > > +}
> > > > +#endif
> > > > +
> > > > G_GNUC_INTERNAL
> > > > void spice_usbredir_channel_connect_device_async(
> > > > SpiceUsbredirChannel
> > > > *channel,
> > > > @@ -331,9 +356,6 @@ void spice_usbredir_channel_connect_device_async(
> > > > {
> > > > SpiceUsbredirChannelPrivate *priv = channel->priv;
> > > > GTask *task;
> > > > -#ifndef USE_POLKIT
> > > > - GError *err = NULL;
> > > > -#endif
> > > >
> > > > g_return_if_fail(SPICE_IS_USBREDIR_CHANNEL(channel));
> > > > g_return_if_fail(device != NULL);
> > > > @@ -376,15 +398,7 @@ void spice_usbredir_channel_connect_device_async(
> > > > channel);
> > > > return;
> > > > #else
> > > > - if (!spice_usbredir_channel_open_device(channel, &err)) {
> > > > - g_task_return_error(task, err);
> > > > - libusb_unref_device(priv->device);
> > > > - priv->device = NULL;
> > > > - g_boxed_free(spice_usb_device_get_type(), priv->spice_device);
> > > > - priv->spice_device = NULL;
> > > > - } else {
> > > > - g_task_return_boolean(task, TRUE);
> > >
> > > Only looked at the diff, not at the full code, but this
> > > g_task_return_boolean(task, TRUE); is gone from the threaded version, is
> > > this intentional?
> > >
> >
> > Good catch. That was unintentional.
> >
> >
> > > Christophe
> > _______________________________________________
> > Spice-devel mailing list
> > Spice-devel@xxxxxxxxxxxxxxxxxxxxx
> > https://lists.freedesktop.org/mailman/listinfo/spice-devel
> _______________________________________________
> Spice-devel mailing list
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