On Mon, 16 Oct 2023 09:52:41 +0200
Cédric Le Goater <clg@xxxxxxxxxx> wrote:
> On 10/13/23 21:56, Alex Williamson wrote:
> > Found via kmemleak, eventfd context is leaked if not explicitly torn
> > down by userspace. Clear pointers to track released contexts. Also
> > remove unused irq_fd field in mtty structure, set but never used.
>
> This could be 2 different patches, one cleanup and one fix.
Of course.
> > Fixes: 9d1a546c53b4 ("docs: Sample driver to demonstrate how to use Mediated device framework.")
> > Signed-off-by: Alex Williamson <alex.williamson@xxxxxxxxxx>
> > ---
> > samples/vfio-mdev/mtty.c | 28 +++++++++++++++++++++++-----
> > 1 file changed, 23 insertions(+), 5 deletions(-)
> >
> > diff --git a/samples/vfio-mdev/mtty.c b/samples/vfio-mdev/mtty.c
> > index 5af00387c519..0a2760818e46 100644
> > --- a/samples/vfio-mdev/mtty.c
> > +++ b/samples/vfio-mdev/mtty.c
> > @@ -127,7 +127,6 @@ struct serial_port {
> > /* State of each mdev device */
> > struct mdev_state {
> > struct vfio_device vdev;
> > - int irq_fd;
> > struct eventfd_ctx *intx_evtfd;
> > struct eventfd_ctx *msi_evtfd;
> > int irq_index;
> > @@ -938,8 +937,10 @@ static int mtty_set_irqs(struct mdev_state *mdev_state, uint32_t flags,
> > {
> > if (flags & VFIO_IRQ_SET_DATA_NONE) {
> > pr_info("%s: disable INTx\n", __func__);
> > - if (mdev_state->intx_evtfd)
> > + if (mdev_state->intx_evtfd) {
> > eventfd_ctx_put(mdev_state->intx_evtfd);
> > + mdev_state->intx_evtfd = NULL;
> > + }
> > break;
> > }
> >
> > @@ -955,7 +956,6 @@ static int mtty_set_irqs(struct mdev_state *mdev_state, uint32_t flags,
> > break;
> > }
>
> Shouln't mdev_state->intx_evtfd value be tested before calling
> eventfd_ctx() ?
The state of mtty interrupt handling is really quite atrocious, it's a
pretty significant overhaul to really make it comply with the SET_IRQS
ioctl. I'll see what I can do, but it's so broken that I hope you
won't insist on splitting out each fix. Thanks,
Alex
> > mdev_state->intx_evtfd = evt;
> > - mdev_state->irq_fd = fd;
> > mdev_state->irq_index = index;
> > break;
> > }
> > @@ -971,8 +971,10 @@ static int mtty_set_irqs(struct mdev_state *mdev_state, uint32_t flags,
> > break;
> > case VFIO_IRQ_SET_ACTION_TRIGGER:
> > if (flags & VFIO_IRQ_SET_DATA_NONE) {
> > - if (mdev_state->msi_evtfd)
> > + if (mdev_state->msi_evtfd) {
> > eventfd_ctx_put(mdev_state->msi_evtfd);
> > + mdev_state->msi_evtfd = NULL;
> > + }
> > pr_info("%s: disable MSI\n", __func__);
> > mdev_state->irq_index = VFIO_PCI_INTX_IRQ_INDEX;
> > break;
> > @@ -993,7 +995,6 @@ static int mtty_set_irqs(struct mdev_state *mdev_state, uint32_t flags,
> > break;
> > }
> > mdev_state->msi_evtfd = evt;
> > - mdev_state->irq_fd = fd;
> > mdev_state->irq_index = index;
> > }
> > break;
> > @@ -1262,6 +1263,22 @@ static unsigned int mtty_get_available(struct mdev_type *mtype)
> > return atomic_read(&mdev_avail_ports) / type->nr_ports;
> > }
> >
> > +static void mtty_close(struct vfio_device *vdev)
> > +{
> > + struct mdev_state *mdev_state =
> > + container_of(vdev, struct mdev_state, vdev);
> > +
> > + if (mdev_state->intx_evtfd) {
> > + eventfd_ctx_put(mdev_state->intx_evtfd);
> > + mdev_state->intx_evtfd = NULL;
> > + }
> > + if (mdev_state->msi_evtfd) {
> > + eventfd_ctx_put(mdev_state->msi_evtfd);
> > + mdev_state->msi_evtfd = NULL;
> > + }
> > + mdev_state->irq_index = -1;
> > +}
> > +
> > static const struct vfio_device_ops mtty_dev_ops = {
> > .name = "vfio-mtty",
> > .init = mtty_init_dev,
> > @@ -1273,6 +1290,7 @@ static const struct vfio_device_ops mtty_dev_ops = {
> > .unbind_iommufd = vfio_iommufd_emulated_unbind,
> > .attach_ioas = vfio_iommufd_emulated_attach_ioas,
> > .detach_ioas = vfio_iommufd_emulated_detach_ioas,
> > + .close_device = mtty_close,
> > };
> >
> > static struct mdev_driver mtty_driver = {
>
