linux-kernel - [PATCH AUTOSEL 5.2 119/185] media: aspeed-video: address a protential usage of an unitialized var

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Message-Id: <20190922184924.32534-119-sashal@kernel.org>
Date:   Sun, 22 Sep 2019 14:48:17 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Mauro Carvalho Chehab <mchehab+samsung@...nel.org>,
        Eddie James <eajames@...ux.ibm.com>,
        Sasha Levin <sashal@...nel.org>, linux-media@...r.kernel.org
Subject: [PATCH AUTOSEL 5.2 119/185] media: aspeed-video: address a protential usage of an unitialized var

From: Mauro Carvalho Chehab <mchehab+samsung@...nel.org>

[ Upstream commit 31b8b0bd6e55c3ea5a08bb8141fa5d3c90600e3b ]

While this might not occur in practice, if the device is doing
the right thing, it would be teoretically be possible to have
both hsync_counter and vsync_counter negatives.

If this ever happen, ctrl will be undefined, but the driver
will still call:

	aspeed_video_update(video, VE_CTRL, 0, ctrl);

Change the code to prevent this to happen.

This was warned by cppcheck:

	[drivers/media/platform/aspeed-video.c:653]: (error) Uninitialized variable: ctrl

Reviewed-by: Eddie James <eajames@...ux.ibm.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@...nel.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/media/platform/aspeed-video.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/media/platform/aspeed-video.c b/drivers/media/platform/aspeed-video.c
index de0f192afa8b1..388c32a11345d 100644
--- a/drivers/media/platform/aspeed-video.c
+++ b/drivers/media/platform/aspeed-video.c
@@ -632,7 +632,7 @@ static void aspeed_video_check_and_set_polarity(struct aspeed_video *video)
 	}
 
 	if (hsync_counter < 0 || vsync_counter < 0) {
-		u32 ctrl;
+		u32 ctrl = 0;
 
 		if (hsync_counter < 0) {
 			ctrl = VE_CTRL_HSYNC_POL;
@@ -652,7 +652,8 @@ static void aspeed_video_check_and_set_polarity(struct aspeed_video *video)
 				V4L2_DV_VSYNC_POS_POL;
 		}
 
-		aspeed_video_update(video, VE_CTRL, 0, ctrl);
+		if (ctrl)
+			aspeed_video_update(video, VE_CTRL, 0, ctrl);
 	}
 }
 
-- 
2.20.1