Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider: - [Medium] drm/tiny: trigger5: unclipped src rect in trigger5_plane_atomic_update() --
commit 56412e719e880a97ad42bea1ca53d34f2a12fdb6 Author: Ho Jie Feng <[email protected]> drm/tiny: trigger5: Add MCT Trigger 5 USB display driver This commit adds a DRM driver for USB 3 to HDMI and VGA display adapters based on the MCT Trigger 5 chipset, implementing modesetting, USB framebuffer updates, connector detection, and EDID retrieval. > diff --git a/drivers/gpu/drm/tiny/trigger5.c b/drivers/gpu/drm/tiny/trigger5.c > new file mode 100644 > index 0000000000000..d0ab06bab8d73 > --- /dev/null > +++ b/drivers/gpu/drm/tiny/trigger5.c [ ... ] > +static enum drm_mode_status > +trigger5_crtc_mode_valid(struct drm_crtc *crtc, > + const struct drm_display_mode *mode) > +{ > + struct trigger5_pll pll; > + u64 err, ppm; > + > + if (mode->hsync_end <= mode->hsync_start || > + mode->htotal <= mode->hsync_end || > + mode->htotal > U16_MAX + 1) > + return MODE_H_ILLEGAL; > + > + if (mode->vsync_end <= mode->vsync_start || > + mode->vtotal <= mode->vsync_end || > + mode->vtotal > U16_MAX + 1) > + return MODE_V_ILLEGAL; > + > + if (trigger5_mode_buf_len(mode) > TRIGGER5_TRANSFER_BUF_SIZE) > + return MODE_MEM; [ ... ] > +static int trigger5_plane_atomic_check(struct drm_plane *plane, > + struct drm_atomic_commit *state) > +{ [ ... ] > + ret = drm_atomic_helper_check_plane_state(new_plane_state, > + new_crtc_state, > + DRM_PLANE_NO_SCALING, > + DRM_PLANE_NO_SCALING, > + false, false); > + if (ret || !new_plane_state->visible) > + return ret; [ ... ] > +static void trigger5_plane_atomic_update(struct drm_plane *plane, > + struct drm_atomic_commit *atomic_state) > +{ [ ... ] > + current_transfer = > + &trigger5->transfers[trigger5->current_transfer]; > + previous_transfer = &trigger5->transfers[1 - > trigger5->current_transfer]; > + > + src_rect = drm_plane_state_src(state); > + > + /* Match drm_atomic_helper_damage_iter_init() rounding. */ > + src_rect.x1 >>= 16; > + src_rect.y1 >>= 16; > + src_rect.x2 = (src_rect.x2 >> 16) + !!(src_rect.x2 & 0xffff); > + src_rect.y2 = (src_rect.y2 >> 16) + !!(src_rect.y2 & 0xffff); > + > + /* Latency reduction: requeue with the latest frame data. */ > + if (cancel_work(&previous_transfer->transfer_work)) { > + complete(&previous_transfer->frame_complete); > + > + trigger5_merge_rect(¤t_rect, > &previous_transfer->transfer_rect); > + > + current_transfer = previous_transfer; > + trigger5->current_transfer = !trigger5->current_transfer; > + } > + > + /* Damage deferred by an earlier failed update. */ > + trigger5_merge_rect(¤t_rect, &trigger5->pending_rect); > + trigger5_clear_rect(&trigger5->pending_rect); > + > + /* Clip merged damage to the new resolution. */ > + if (!drm_rect_intersect(¤t_rect, &src_rect)) > + goto exit; > + > + width = drm_rect_width(¤t_rect); > + height = drm_rect_height(¤t_rect); > + payload_len = array3_size(width, height, 3); > + frame_len = size_add(payload_len, sizeof(*header)); > + > + if (drm_WARN_ON_ONCE(plane->dev, frame_len > current_transfer->buf.len)) > + goto exit; [Severity: Medium] Can src_rect in trigger5_plane_atomic_update() exceed the active CRTC mode dimensions and overflow the 8 MiB limit checked in trigger5_crtc_mode_valid()? In trigger5_plane_atomic_check(), drm_atomic_helper_check_plane_state() clips new_plane_state->dst to (0, 0)-(mode->hdisplay, mode->vdisplay) and stores the clipped source coordinates in new_plane_state->src, while leaving the unclipped new_plane_state->src_x, src_y, src_w, and src_h unchanged. Because drm_atomic_helper_check_plane_state() checks drm_rect_equals(dst, &clip) after clipping dst, a plane update on a larger framebuffer with crtc_x <= 0, crtc_y <= 0, and unclipped src_w/src_h larger than mode->hdisplay and mode->vdisplay passes validation. In addition, drm_atomic_helper_check_plane_state() does not reject non-zero 16.16 fixed-point fractional bits in src_x or src_y when panning within a larger framebuffer. Rounding src_rect.x1/y1 down and src_rect.x2/y2 up expands the dimensions of src_rect by an extra pixel to mode->hdisplay + 1 and mode->vdisplay + 1. Because trigger5_plane_atomic_update() builds src_rect from the unclipped drm_plane_state_src(state) rather than the clipped state->src, current_rect after drm_rect_intersect(¤t_rect, &src_rect) can exceed mode->hdisplay x mode->vdisplay. When frame_len exceeds current_transfer->buf.len, this triggers drm_WARN_ON_ONCE() and jumps to exit after trigger5->pending_rect was already cleared and previous_transfer->transfer_work was potentially cancelled, dropping that damage. When frame_len still fits within current_transfer->buf.len, the bulk header is sent with width and height larger than the configured mode and offsets computed relative to the unclipped off-screen src_rect.x1/y1. Should trigger5_plane_atomic_update() use state->src instead of drm_plane_state_src(state), and should trigger5_plane_atomic_check() reject fractional source coordinates or unclipped planes? -- Sashiko AI review ยท https://sashiko.dev/#/patchset/[email protected]?part=1
