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([2a01:e0a:280:24f0:9db0:474c:ff43:9f5c]) by smtp.gmail.com with ESMTPSA id r30-20020a05620a03de00b0076ca9f79e1fsm2799111qkm.46.2023.10.16.00.52.43 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 16 Oct 2023 00:52:43 -0700 (PDT) Message-ID: <04d9af1d-e459-4431-bea3-679ade88f7d5@redhat.com> Date: Mon, 16 Oct 2023 09:52:41 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 1/2] vfio/mtty: Fix eventfd leak Content-Language: en-US To: Alex Williamson Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org References: <20231013195653.1222141-1-alex.williamson@redhat.com> <20231013195653.1222141-2-alex.williamson@redhat.com> From: =?UTF-8?Q?C=C3=A9dric_Le_Goater?= In-Reply-To: <20231013195653.1222141-2-alex.williamson@redhat.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. > Fixes: 9d1a546c53b4 ("docs: Sample driver to demonstrate how to use Mediated device framework.") > Signed-off-by: Alex Williamson > --- > 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() ? Thanks, C. > 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 = {