4.20-stable review patch. If anyone has any objections, please let me know.
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[ Upstream commit f75df8d4b4fabfad7e3cba2debfad12741c6fde7 ]
Blitting an image with "negative" offsets is not working since there is no clipping. It hopefully just crashes. For the bootup logo, there is protection so that blitting does not happen as the image is drawn further and further to the right (ROTATE_UR) or further and further down (ROTATE_CW). There is however no protection when drawing in the opposite directions (ROTATE_UD and ROTATE_CCW).
Add back this protection.
The regression is 20-odd years old but the mindless warning-killing mentality displayed in commit 34bdb666f4b2 ("fbdev: fbmem: remove positive test on unsigned values") is also to blame, methinks.
Fixes: 448d479747b8 ("fbdev: fb_do_show_logo() updates") Signed-off-by: Peter Rosin peda@axentia.se Cc: Tomi Valkeinen tomi.valkeinen@ti.com Cc: Fabian Frederick ffrederick@users.sourceforge.net Cc: Geert Uytterhoeven geert+renesas@glider.be cc: Geoff Levand geoff@infradead.org Cc: James Simmons jsimmons@users.sf.net Signed-off-by: Bartlomiej Zolnierkiewicz b.zolnierkie@samsung.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/video/fbdev/core/fbmem.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/drivers/video/fbdev/core/fbmem.c b/drivers/video/fbdev/core/fbmem.c index 861bf8081619..7dd6924feaa8 100644 --- a/drivers/video/fbdev/core/fbmem.c +++ b/drivers/video/fbdev/core/fbmem.c @@ -436,7 +436,9 @@ 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; x++) { + u32 dx = image->dx; + + for (x = 0; x < num && image->dx <= dx; x++) { info->fbops->fb_imageblit(info, image); image->dx -= image->width + 8; } @@ -448,7 +450,9 @@ 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; x++) { + u32 dy = image->dy; + + for (x = 0; x < num && image->dy <= dy; x++) { info->fbops->fb_imageblit(info, image); image->dy -= image->height + 8; }