kernel/linux.git/drivers/gpu/drm/virtio, branch v6.6.150

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

2026-08-03T09:15:24+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

2026-08-03T09:15:10+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()

2026-06-19T11:39:32+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

2026-06-19T11:39:31+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

2026-06-01T15:43:09+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: New fence for every plane update

2025-02-17T08:40:04+00:00

[ Upstream commit d3c55b8ab6fe5fa2e7ab02efd36d09c39ee5022f ] Having a fence linked to a virtio_gpu_framebuffer in the plane update sequence would cause conflict when several planes referencing the same framebuffer (e.g. Xorg screen covering multi-displays configured for an extended mode) and those planes are updated concurrently. So it is needed to allocate a fence for every plane state instead of the framebuffer. Signed-off-by: Dongwon Kim [dmitry.osipenko@collabora.com: rebase, fix up, edit commit message] Signed-off-by: Dmitry Osipenko Acked-by: Vivek Kasireddy Reviewed-by: Rob Clark Link: https://patchwork.freedesktop.org/patch/msgid/20241020230803.247419-2-dmitry.osipenko@collabora.com Signed-off-by: Sasha Levin

drm/virtio: Fix type of dma-fence context variable

2024-08-11T10:47:26+00:00

commit 445d336cd15860f1efb441e6d694f829fbf679eb upstream. Type of DMA fence context is u64. Fence-waiting code uses u32 for the context variable, fix it. Fixes: e4812ab8e6b1 ("drm/virtio: Refactor and optimize job submission code path") Cc: # v6.4+ Signed-off-by: Dmitry Osipenko Reviewed-by: Rob Clark Link: https://patchwork.freedesktop.org/patch/msgid/20240714205009.3408298-1-dmitry.osipenko@collabora.com Signed-off-by: Greg Kroah-Hartman

drm/virtio: Set segment size for virtio_gpu device

2024-02-23T08:25:01+00:00

commit 9c64e749cebd9c2d3d55261530a98bcccb83b950 upstream. Set the segment size of the virtio_gpu device to the value used by the drm helpers when allocating sg lists to fix the following complaint from DMA_API debug code: DMA-API: virtio-pci 0000:07:00.0: mapping sg segment longer than device claims to support [len=262144] [max=65536] Cc: stable@vger.kernel.org Tested-by: Zhenyu Zhang Acked-by: Vivek Kasireddy Signed-off-by: Sebastian Ott Signed-off-by: Dmitry Osipenko Link: https://patchwork.freedesktop.org/patch/msgid/7258a4cc-da16-5c34-a042-2a23ee396d56@redhat.com Signed-off-by: Greg Kroah-Hartman

drm/virtio: Disable damage clipping if FB changed since last page-flip

2024-02-01T00:19:08+00:00

commit 0240db231dfe5ee5b7a3a03cba96f0844b7a673d upstream. The driver does per-buffer uploads and needs to force a full plane update if the plane's attached framebuffer has change since the last page-flip. Fixes: 01f05940a9a7 ("drm/virtio: Enable fb damage clips property for the primary plane") Cc: # v6.4+ Reported-by: nerdopolis Closes: https://bugzilla.kernel.org/show_bug.cgi?id=218115 Suggested-by: Sima Vetter Signed-off-by: Javier Martinez Canillas Reviewed-by: Thomas Zimmermann Reviewed-by: Zack Rusin Acked-by: Sima Vetter Link: https://patchwork.freedesktop.org/patch/msgid/20231123221315.3579454-3-javierm@redhat.com Signed-off-by: Greg Kroah-Hartman

drm: Disable the cursor plane on atomic contexts with virtualized drivers

2024-02-01T00:19:08+00:00

commit 4e3b70da64a53784683cfcbac2deda5d6e540407 upstream. Cursor planes on virtualized drivers have special meaning and require that the clients handle them in specific ways, e.g. the cursor plane should react to the mouse movement the way a mouse cursor would be expected to and the client is required to set hotspot properties on it in order for the mouse events to be routed correctly. This breaks the contract as specified by the "universal planes". Fix it by disabling the cursor planes on virtualized drivers while adding a foundation on top of which it's possible to special case mouse cursor planes for clients that want it. Disabling the cursor planes makes some kms compositors which were broken, e.g. Weston, fallback to software cursor which works fine or at least better than currently while having no effect on others, e.g. gnome-shell or kwin, which put virtualized drivers on a deny-list when running in atomic context to make them fallback to legacy kms and avoid this issue. Signed-off-by: Zack Rusin Fixes: 681e7ec73044 ("drm: Allow userspace to ask for universal plane list (v2)") Cc: # v5.4+ Cc: Maarten Lankhorst Cc: Maxime Ripard Cc: Thomas Zimmermann Cc: David Airlie Cc: Daniel Vetter Cc: Dave Airlie Cc: Gerd Hoffmann Cc: Hans de Goede Cc: Gurchetan Singh Cc: Chia-I Wu Cc: dri-devel@lists.freedesktop.org Cc: virtualization@lists.linux-foundation.org Cc: spice-devel@lists.freedesktop.org Acked-by: Pekka Paalanen Reviewed-by: Javier Martinez Canillas Acked-by: Simon Ser Signed-off-by: Javier Martinez Canillas Link: https://patchwork.freedesktop.org/patch/msgid/20231023074613.41327-2-aesteve@redhat.com Signed-off-by: Greg Kroah-Hartman