From: Zsolt Kajtar <soci@c64.rulez.org>
Date: Thu, 21 Aug 2025 02:42:48 +0000 (+0200)
Subject: fbdev: core: Fix ubsan warning in pixel_to_pat
X-Git-Tag: v6.17.8~134
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f3964e93e34942cc407fbe8205062368fab6df3f;p=thirdparty%2Fkernel%2Fstable.git

fbdev: core: Fix ubsan warning in pixel_to_pat

[ Upstream commit aad1d99beaaf132e2024a52727c24894cdf9474a ]

It could be triggered on 32 bit big endian machines at 32 bpp in the
pattern realignment. In this case just return early as the result is
an identity.

Signed-off-by: Zsolt Kajtar <soci@c64.rulez.org>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---

diff --git a/drivers/video/fbdev/core/fb_fillrect.h b/drivers/video/fbdev/core/fb_fillrect.h
index 66042e534de77..f366670a53af8 100644
--- a/drivers/video/fbdev/core/fb_fillrect.h
+++ b/drivers/video/fbdev/core/fb_fillrect.h
@@ -92,8 +92,7 @@ static unsigned long pixel_to_pat(int bpp, u32 color)
 		pattern = pattern | pattern << bpp;
 		break;
 	default:
-		pattern = color;
-		break;
+		return color;
 	}
 #ifndef __LITTLE_ENDIAN
 	pattern <<= (BITS_PER_LONG % bpp);