From 07f5d021d764ede78cd9b6857b665887e58eb42a Mon Sep 17 00:00:00 2001 From: Jocelyn Falempe Date: Thu, 9 Oct 2025 14:24:50 +0200 Subject: [PATCH] drm/panic: Fix qr_code, ensure vmargin is positive [ Upstream commit 4fcffb5e5c8c0c8e2ad9c99a22305a0afbecc294 ] Depending on qr_code size and screen size, the vertical margin can be negative, that means there is not enough room to draw the qr_code. So abort early, to avoid a segfault by trying to draw at negative coordinates. Fixes: cb5164ac43d0f ("drm/panic: Add a QR code panic screen") Reviewed-by: Javier Martinez Canillas Link: https://lore.kernel.org/r/20251009122955.562888-4-jfalempe@redhat.com Signed-off-by: Jocelyn Falempe Signed-off-by: Sasha Levin --- drivers/gpu/drm/drm_panic.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/drm_panic.c b/drivers/gpu/drm/drm_panic.c index 932a54b67479..0aa87eafdacd 100644 --- a/drivers/gpu/drm/drm_panic.c +++ b/drivers/gpu/drm/drm_panic.c @@ -618,7 +618,10 @@ static int _draw_panic_static_qr_code(struct drm_scanout_buffer *sb) pr_debug("QR width %d and scale %d\n", qr_width, scale); r_qr_canvas = DRM_RECT_INIT(0, 0, qr_canvas_width * scale, qr_canvas_width * scale); - v_margin = (sb->height - drm_rect_height(&r_qr_canvas) - drm_rect_height(&r_msg)) / 5; + v_margin = sb->height - drm_rect_height(&r_qr_canvas) - drm_rect_height(&r_msg); + if (v_margin < 0) + return -ENOSPC; + v_margin /= 5; drm_rect_translate(&r_qr_canvas, (sb->width - r_qr_canvas.x2) / 2, 2 * v_margin); r_qr = DRM_RECT_INIT(r_qr_canvas.x1 + QR_MARGIN * scale, r_qr_canvas.y1 + QR_MARGIN * scale, -- 2.47.3