Never reached lkml due to the HTML.
Resending, with a CC to linux-fbdev added.
---------- Forwarded message ----------
From: Levin Du <zsle...@gmail.com>
Date: 2012/7/12
Subject: video/fbmem.c: Fix __u32 >= 0 condition in fb_do_show_logo.
To: linux-kernel@vger.kernel.org
Cc: b...@neruo.com
Dear all,
Since dx or dy in struct fb_image is unsigned 32 bit integer:
struct fb_image {
__u32 dx; /* Where to place image */
__u32 dy;
...
}
In fb_do_show_logo(), image->dx or image->dy will always meet the >= 0
condition.
if the logo is large enough (same as to the whole screen, for example) and
rotate is UD or CCW, and image->dx or image->dy will results in a
large value which
makes info->fbops->fb_imageblit fail miserably.
Here is the raw patch:
diff --git a/drivers/video/fbmem.c b/drivers/video/fbmem.c
index ad93629..34a0ba3 100644
--- a/drivers/video/fbmem.c
+++ b/drivers/video/fbmem.c
@@ -419,6 +419,7 @@ static void fb_do_show_logo(struct fb_info *info,
struct fb_image *image,
int rotate, unsigned int num)
{
unsigned int x;
+ long d;
if (rotate == FB_ROTATE_UR) {
for (x = 0;
@@ -428,9 +429,10 @@ static void fb_do_show_logo(struct fb_info *info,
struct fb_image *image,
image->dx += image->width + 8;
}
} else if (rotate == FB_ROTATE_UD) {
- for (x = 0; x < num && image->dx >= 0; x++) {
+ d = image->dx;
+ for (x = 0; x < num && d >= 0; x++) {
info->fbops->fb_imageblit(info, image);
- image->dx -= image->width + 8;
+ d -= image->width + 8;
}
} else if (rotate == FB_ROTATE_CW) {
for (x = 0;
@@ -440,9 +442,10 @@ static void fb_do_show_logo(struct fb_info *info,
struct fb_image *image,
image->dy += image->height + 8;
}
} else if (rotate == FB_ROTATE_CCW) {
- for (x = 0; x < num && image->dy >= 0; x++) {
+ d = image->dy;
+ for (x = 0; x < num && d >= 0; x++) {
info->fbops->fb_imageblit(info, image);
- image->dy -= image->height + 8;
+ d -= image->height + 8;
}
}
}
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- ge...@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
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