kernel/linux.git/drivers/gpu/drm/virtio, branch v6.18.48

drm/virtio: Don't detach GEM from a non-created context

2026-08-03T09:21:52+00:00

commit d489a5305b9d5480d6fb97d5636f5f4b1e0b3827 upstream. Applies the same treatment as commit 7cf6dd467e87 ("drm/virtio: Don't attach GEM to a non-created context in gem_object_open()") to virtio_gpu_gem_object_close() to avoid trying to detach a resource that was never attached due to a context never being created when context_init is supported. Fixes: 086b9f27f0ab ("drm/virtio: Don't create a context with default param if context_init is supported") Cc: # v6.14+ Signed-off-by: Jason Macnak Signed-off-by: Dmitry Osipenko Link: https://patch.msgid.link/20260625170828.3335431-1-natsu@google.com Signed-off-by: Greg Kroah-Hartman

drm/virtio: bound EDID block reads to the response buffer

2026-08-03T09:21:51+00:00

commit 4e1a53892ba7f8a3e1da6bfc53c83ae7c812dccd upstream. virtio_get_edid_block() validates the read offset only against the device-supplied resp->size field, never against the fixed-size resp->edid array. The EDID block index is driven by the device-supplied extension count, so a malicious virtio-gpu backend can advertise a large size together with a high block count and read far past the array into adjacent kernel memory, which is then surfaced in the parsed EDID (an out-of-bounds read / info leak). Also reject any read whose end exceeds the size of the edid array. Conforming EDID responses stay within the array and are unaffected. Fixes: b4b01b4995fb ("drm/virtio: add edid support") Cc: stable@vger.kernel.org Signed-off-by: Bryam Vargas Signed-off-by: Dmitry Osipenko Link: https://patch.msgid.link/20260620-b4-disp-22bba7bf-v1-1-b95924cee742@proton.me Signed-off-by: Greg Kroah-Hartman

drm/virtio: fix deadlock in display_info_cb by removing hotplug from dequeue worker

2026-08-03T09:21:25+00:00

[ Upstream commit d1b894c5bbb3fee0012bd14356286dc2384e8213 ] A probe-time deadlock can occur between the dequeue worker and drm_client_register(). During probe, drm_client_register() holds clientlist_mutex and calls the fbdev hotplug callback, which triggers an atomic commit that ends up sleeping in virtio_gpu_queue_ctrl_sgs() waiting for virtqueue space. The dequeue worker that would free that space calls virtio_gpu_cmd_get_display_info_cb(), which invokes drm_kms_helper_hotplug_event() -> drm_client_dev_hotplug(), attempting to acquire the same clientlist_mutex. Since wake_up() is only called after the resp_cb loop, the probe thread is never woken and both threads deadlock. Fix this by removing the hotplug notification from virtio_gpu_cmd_get_display_info_cb(). The display data (outputs[i].info) is still updated synchronously in the callback. For the init path, drm_client_register() already fires an initial hotplug when the client is registered, which picks up the connector state updated by display_info_cb. For the runtime config_changed path, add a wait_event_timeout() in config_changed_work_func() so that display_info_cb updates the connector data before the hotplug notification is sent. Also replace drm_helper_hpd_irq_event() with drm_kms_helper_hotplug_event() since virtio-gpu never calls drm_kms_helper_poll_init() and thus drm_helper_hpd_irq_event() always returns false without doing anything. Fixes: 27655b9bb9f0 ("drm/client: Send hotplug event after registering a client") Closes: https://syzkaller.appspot.com/bug?id=d6dd6f86d3aaf7eebe7406e45c1c6e549453f224 Closes: https://syzkaller.appspot.com/bug?id=908bd910da5dd79b88de4cf7baf376cc873a922e Suggested-by: Dmitry Osipenko Signed-off-by: Ryosuke Yasuoka Signed-off-by: Dmitry Osipenko Link: https://patch.msgid.link/20260713-virtiogpu_syzbot-v2-1-2958fa37d46d@redhat.com Signed-off-by: Sasha Levin

drm/virtio: fix dma_fence refcount leak on error in virtio_gpu_dma_fence_wait()

2026-06-19T11:44:04+00:00

commit 3f26bb732cc136ab20176697c92f32c9c84cb125 upstream. dma_fence_unwrap_for_each() internally calls dma_fence_unwrap_first() which does cursor->chain = dma_fence_get(head), taking an extra reference. On normal loop completion, dma_fence_unwrap_next() releases this via dma_fence_chain_walk() -> dma_fence_put(). When virtio_gpu_do_fence_wait() fails and the function returns early from inside the loop, the cursor->chain reference is never released. This is the only caller in the entire kernel that does an early return inside dma_fence_unwrap_for_each. Add dma_fence_put(itr.chain) before the early return. Cc: stable@vger.kernel.org Fixes: eba57fb5498f ("drm/virtio: Wait for each dma-fence of in-fence array individually") Signed-off-by: Wentao Liang Reviewed-by: Dmitry Osipenko Signed-off-by: Dmitry Osipenko Link: https://patch.msgid.link/20260607090303.92423-1-vulab@iscas.ac.cn Signed-off-by: Greg Kroah-Hartman

drm/virtio: Fix driver removal with disabled KMS

2026-06-19T11:44:01+00:00

[ Upstream commit f329e8325e054bd6d84d10904f8dd51137281b92 ] DRM atomic and modesetting aren't initialized if virtio-gpu driver built with disabled KMS, leading to access of uninitialized data on driver removal/unbinding and crashing kernel. Fix it by skipping shutting down atomic core with unavailable KMS. Fixes: 72122c69d717 ("drm/virtio: Add option to disable KMS support") Signed-off-by: Dmitry Osipenko Tested-by: Ryosuke Yasuoka Reviewed-by: Ryosuke Yasuoka Link: https://patch.msgid.link/20260604122743.13383-1-dmitry.osipenko@collabora.com Signed-off-by: Sasha Levin

drm/virtio: use uninterruptible resv lock for plane updates

2026-06-01T15:50:47+00:00

commit 9af1b6e175c82daf4b423da339a722d8e67a735a upstream. virtio_gpu_cursor_plane_update() and virtio_gpu_resource_flush() lock the framebuffer BO's dma_resv via virtio_gpu_array_lock_resv() and ignore its return value. The function can fail with -EINTR from dma_resv_lock_interruptible() (signal during lock wait) or with -ENOMEM from dma_resv_reserve_fences() (fence slot allocation), leaving the resv lock not held. The queue path then walks the object array and calls dma_resv_add_fence(), which requires the lock held; with lockdep enabled this trips dma_resv_assert_held(): WARNING: drivers/dma-buf/dma-resv.c:296 at dma_resv_add_fence+0x71e/0x840 Call Trace: virtio_gpu_array_add_fence virtio_gpu_queue_ctrl_sgs virtio_gpu_queue_fenced_ctrl_buffer virtio_gpu_cursor_plane_update drm_atomic_helper_commit_planes drm_atomic_helper_commit_tail commit_tail drm_atomic_helper_commit drm_atomic_commit drm_atomic_helper_update_plane __setplane_atomic drm_mode_cursor_universal drm_mode_cursor_common drm_mode_cursor_ioctl drm_ioctl __x64_sys_ioctl Beyond the WARN, mutating the dma_resv fence list without the lock races with concurrent readers/writers and can corrupt the list. Both call sites run inside the .atomic_update plane callback, which DRM atomic helpers do not allow to fail (by the time it runs, the commit has been signed off to userspace and there is no clean rollback path). Moving the lock acquisition to .prepare_fb was rejected because the broader lock scope deadlocks against other BO locking paths in the same atomic commit. Introduce virtio_gpu_lock_one_resv_uninterruptible() that uses dma_resv_lock() instead of dma_resv_lock_interruptible(). This eliminates the -EINTR failure mode -- the realistic syzbot trigger -- without extending the lock hold across the commit. The helper locks a single BO and rejects nents > 1 with -EINVAL; both fix sites lock exactly one BO. Use it from virtio_gpu_cursor_plane_update() and virtio_gpu_resource_flush(); check the return value to handle the remaining -ENOMEM case from dma_resv_reserve_fences() by freeing the objs and skipping the plane update for that frame. The framebuffer BOs touched here are not shared with other contexts and lock contention is expected to be brief, so the loss of signal-interruptibility is acceptable. Other callers of virtio_gpu_array_lock_resv() (the ioctl paths) continue to use the interruptible variant. The bug was reported by syzbot, triggered via fault injection (fail_nth) on the DRM_IOCTL_MODE_CURSOR path, which forces the -ENOMEM branch in dma_resv_reserve_fences(). Reported-by: syzbot+72bd3dd3a5d5f39a0271@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=72bd3dd3a5d5f39a0271 Fixes: 5cfd31c5b3a3 ("drm/virtio: fix virtio_gpu_cursor_plane_update().") Cc: stable@vger.kernel.org Signed-off-by: Deepanshu Kartikey Signed-off-by: Dmitry Osipenko Link: https://patch.msgid.link/20260519082247.34470-1-kartikey406@gmail.com Signed-off-by: Greg Kroah-Hartman

drm/virtio: Allow importing prime buffers when 3D is enabled

2026-05-23T11:06:34+00:00

[ Upstream commit df4dc947c46bb9f80038f52c6e38cb2d40c10e50 ] This functionality was added for using a KMS-only virtgpu with a physical (or SR-IOV) headless GPU in passthrough, but it should not be restricted to KMS-only mode. It can be used with cross-domain to pass guest memfds to the host compositor with zero copies (using udmabuf on both sides). Drop the check for the absence of virgl_3d to allow for more use cases. Fixes: ca77f27a2665 ("drm/virtio: Import prime buffers from other devices as guest blobs") Signed-off-by: Val Packett Reviewed-by: Dmitry Osipenko Signed-off-by: Dmitry Osipenko Link: https://patch.msgid.link/20251210154755.1119861-2-val@invisiblethingslab.com Signed-off-by: Sasha Levin

drm/virtio: clean up minor codestyle issues

2025-08-20T10:36:45+00:00

Fix codestyle warnings and errors generated by CHECKPATCH in virtio source files. Signed-off-by: Athul Raj Kollareth Signed-off-by: Dmitry Osipenko Link: https://lore.kernel.org/r/20250813062109.5326-1-krathul3152@gmail.com

Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost

2025-08-01T21:17:48+00:00

Pull virtio updates from Michael Tsirkin: - vhost can now support legacy threading if enabled in Kconfig - vsock memory allocation strategies for large buffers have been improved, reducing pressure on kmalloc - vhost now supports the in-order feature. guest bits missed the merge window. - fixes, cleanups all over the place * tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost: (30 commits) vsock/virtio: Allocate nonlinear SKBs for handling large transmit buffers vsock/virtio: Rename virtio_vsock_skb_rx_put() vhost/vsock: Allocate nonlinear SKBs for handling large receive buffers vsock/virtio: Move SKB allocation lower-bound check to callers vsock/virtio: Rename virtio_vsock_alloc_skb() vsock/virtio: Resize receive buffers so that each SKB fits in a 4K page vsock/virtio: Move length check to callers of virtio_vsock_skb_rx_put() vsock/virtio: Validate length in packet header before skb_put() vhost/vsock: Avoid allocating arbitrarily-sized SKBs vhost_net: basic in_order support vhost: basic in order support vhost: fail early when __vhost_add_used() fails vhost: Reintroduce kthread API and add mode selection vdpa: Fix IDR memory leak in VDUSE module exit vdpa/mlx5: Fix release of uninitialized resources on error path vhost-scsi: Fix check for inline_sg_cnt exceeding preallocated limit virtio: virtio_dma_buf: fix missing parameter documentation vhost: Fix typos vhost: vringh: Remove unused functions vhost: vringh: Remove unused iotlb functions ...

drm/virtio: implement virtio_gpu_shutdown

2025-08-01T13:11:07+00:00

Calling drm_dev_unplug() is the drm way to say the device is gone and can not be accessed any more. Cc: Michael S. Tsirkin Signed-off-by: Gerd Hoffmann Reviewed-by: Eric Auger Tested-by: Eric Auger Message-Id: <20250507082821.2710706-1-kraxel@redhat.com> Signed-off-by: Michael S. Tsirkin