From 250854eed5d45a73d81e4137dfd85180af6f2ec3 Mon Sep 17 00:00:00 2001
From: Hans Verkuil <hverkuil@xs4all.nl>
Date: Mon, 8 Oct 2018 15:08:27 -0400
Subject: [PATCH] media: v4l2-tpg: fix kernel oops when enabling HFLIP and OSD
Git-commit: 250854eed5d45a73d81e4137dfd85180af6f2ec3
Patch-mainline: v4.20-rc1
References: bsc#1051510

When the OSD is on (i.e. vivid displays text on top of the test pattern), and
you enable hflip, then the driver crashes.

The cause turned out to be a division of a negative number by an unsigned value.
You expect that -8 / 2U would be -4, but in reality it is 2147483644 :-(

Fixes: 3e14e7a82c1ef ("vivid-tpg: add hor/vert downsampling support to tpg_gen_text")

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Reported-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Cc: <stable@vger.kernel.org>      # for v4.1 and up
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/media/common/v4l2-tpg/v4l2-tpg-core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/media/common/v4l2-tpg/v4l2-tpg-core.c b/drivers/media/common/v4l2-tpg/v4l2-tpg-core.c
index 76b125ebee6d..fa483b95bc5a 100644
--- a/drivers/media/common/v4l2-tpg/v4l2-tpg-core.c
+++ b/drivers/media/common/v4l2-tpg/v4l2-tpg-core.c
@@ -1801,7 +1801,7 @@ typedef struct { u16 __; u8 _; } __packed x24;
 				pos[7] = (chr & (0x01 << 0) ? fg : bg);	\
 			} \
 	\
-			pos += (tpg->hflip ? -8 : 8) / hdiv;	\
+			pos += (tpg->hflip ? -8 : 8) / (int)hdiv;	\
 		}	\
 	}	\
 } while (0)
-- 
2.19.1