linux-kernel - [PATCH AUTOSEL 4.14 08/11] fbdev: core: cfbcopyarea: fix sloppy typing

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Message-ID: <20231029230213.793581-8-sashal@kernel.org>
Date:   Sun, 29 Oct 2023 19:01:59 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Sergey Shtylyov <s.shtylyov@....ru>, Helge Deller <deller@....de>,
        Sasha Levin <sashal@...nel.org>, daniel@...ll.ch,
        linux-fbdev@...r.kernel.org, dri-devel@...ts.freedesktop.org
Subject: [PATCH AUTOSEL 4.14 08/11] fbdev: core: cfbcopyarea: fix sloppy typing

From: Sergey Shtylyov <s.shtylyov@....ru>

[ Upstream commit 7f33df94cf0156f64eee9509bd9b4a178990f613 ]

In cfb_copyarea(), the local variable bits_per_line is needlessly typed as
*unsigned long* -- which is a 32-bit type on the 32-bit arches and a 64-bit
type on the 64-bit arches; that variable's value is derived from the __u32
typed fb_fix_screeninfo::line_length field (multiplied by 8u) and a 32-bit
*unsigned int* type should still be enough to store the # of bits per line.

Found by Linux Verification Center (linuxtesting.org) with the Svace static
analysis tool.

Signed-off-by: Sergey Shtylyov <s.shtylyov@....ru>
Signed-off-by: Helge Deller <deller@....de>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/video/fbdev/core/cfbcopyarea.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/video/fbdev/core/cfbcopyarea.c b/drivers/video/fbdev/core/cfbcopyarea.c
index 6d4bfeecee350..5b80bf3dae504 100644
--- a/drivers/video/fbdev/core/cfbcopyarea.c
+++ b/drivers/video/fbdev/core/cfbcopyarea.c
@@ -382,7 +382,7 @@ void cfb_copyarea(struct fb_info *p, const struct fb_copyarea *area)
 {
 	u32 dx = area->dx, dy = area->dy, sx = area->sx, sy = area->sy;
 	u32 height = area->height, width = area->width;
-	unsigned long const bits_per_line = p->fix.line_length*8u;
+	unsigned int const bits_per_line = p->fix.line_length * 8u;
 	unsigned long __iomem *base = NULL;
 	int bits = BITS_PER_LONG, bytes = bits >> 3;
 	unsigned dst_idx = 0, src_idx = 0, rev_copy = 0;
-- 
2.42.0