Thank you for your contribution! Sashiko AI review found 2 potential issue(s) to consider:
Pre-existing issues: - [High] Use-After-Free due to unsafe access to `connector->state` in the fallback logic without proper locking or addition to the atomic state. - [Medium] Iterator variable `connector_state` leaks from the `for_each_new_connector_in_state` loop when no CRTC-bound connector is found, causing the wrong connector state to be used. -- commit 0c2e0cfd22b820fc8dacf39a623bb3f5f21ff275 Author: Sajal Gupta <[email protected]> drm/gud: fix out-of-bounds write in gud_plane_atomic_check() This commit fixes an out-of-bounds write in the plane property loop of gud_plane_atomic_check(). It drops a redundant addition of the loop index to num_properties, since num_properties is already the correct running index. Link: https://sashiko.dev/#/patchset/20260821071812.16500-1-sajal2005gupta%40gmail.com?part=1 > diff --git a/drivers/gpu/drm/gud/gud_pipe.c b/drivers/gpu/drm/gud/gud_pipe.c > index 5ef887d8485a3..54adc401bc1ba 100644 > --- a/drivers/gpu/drm/gud/gud_pipe.c > +++ b/drivers/gpu/drm/gud/gud_pipe.c [ ... ] > @@ -562,8 +562,8 @@ int gud_plane_atomic_check(struct drm_plane *plane, > goto out; > } > > - req->properties[num_properties + i].prop = cpu_to_le16(prop); > - req->properties[num_properties + i].val = cpu_to_le64(val); > + req->properties[num_properties].prop = cpu_to_le16(prop); > + req->properties[num_properties].val = cpu_to_le64(val); > num_properties++; > } While reviewing this change, I noticed a couple of pre-existing issues earlier in gud_plane_atomic_check(): drivers/gpu/drm/gud/gud_pipe.c:gud_plane_atomic_check() { ... for_each_new_connector_in_state(state, connector, connector_state, i) { if (connector_state->crtc) break; } /* * DRM_IOCTL_MODE_OBJ_SETPROPERTY on the rotation property will not have * the connector included in the state. */ if (!connector_state) { [Severity: Medium] This is a pre-existing issue, but I noticed the iterator variable connector_state is not cleared if the loop completes without hitting the break statement. If userspace submits an atomic commit updating a plane property while simultaneously modifying a disconnected connector, the loop evaluates the disconnected connector and finishes without breaking. This leaves connector_state retaining the disconnected state. Since connector_state is no longer NULL, the fallback check is skipped. Could this cause the hardware check command GUD_REQ_SET_STATE_CHECK to receive the ID of a disconnected connector and misconfigure the display? struct drm_connector_list_iter conn_iter; drm_connector_list_iter_begin(plane->dev, &conn_iter); drm_for_each_connector_iter(connector, &conn_iter) { if (connector->state->crtc) { connector_state = connector->state; break; } } drm_connector_list_iter_end(&conn_iter); } [Severity: High] This is also a pre-existing issue, but does this fallback logic risk a use-after-free by directly accessing connector->state? When an atomic commit updates only a plane property, the fallback logic iterates all system connectors and directly assigns connector_state to connector->state. Because the connector is not added to the atomic state via drm_atomic_get_connector_state(), its lock is not held by the current thread. If a concurrent userspace thread issues a property update on this connector, could it swap and free the old state while gud_connector_fill_properties() is simultaneously reading from it? -- Sashiko AI review ยท https://sashiko.dev/#/patchset/[email protected]?part=1
