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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Kangjie Lu <kjlu@umn.edu>,
        Matthias Schwarzott <zzam@gentoo.org>,
        Sean Young <sean@mess.org>,
        Mauro Carvalho Chehab <mchehab+samsung@kernel.org>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.19 249/276] media: si2165: fix a missing check of return value
Date:   Wed, 29 May 2019 20:06:47 -0700
Message-Id: <20190530030540.713606171@linuxfoundation.org>
In-Reply-To: <20190530030523.133519668@linuxfoundation.org>
References: <20190530030523.133519668@linuxfoundation.org>
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[ Upstream commit 0ab34a08812a3334350dbaf69a018ee0ab3d2ddd ]

si2165_readreg8() may fail. Looking into si2165_readreg8(), we will find
that "val_tmp" will be an uninitialized value when regmap_read() fails.
"val_tmp" is then assigned to "val". So if si2165_readreg8() fails,
"val" will be a random value. Further use will lead to undefined
behaviors. The fix checks if si2165_readreg8() fails, and if so, returns
its error code upstream.

Signed-off-by: Kangjie Lu <kjlu@umn.edu>
Reviewed-by: Matthias Schwarzott <zzam@gentoo.org>
Tested-by: Matthias Schwarzott <zzam@gentoo.org>
Signed-off-by: Sean Young <sean@mess.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/media/dvb-frontends/si2165.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/media/dvb-frontends/si2165.c b/drivers/media/dvb-frontends/si2165.c
index feacd8da421da..d55d8f169dca6 100644
--- a/drivers/media/dvb-frontends/si2165.c
+++ b/drivers/media/dvb-frontends/si2165.c
@@ -275,18 +275,20 @@ static u32 si2165_get_fe_clk(struct si2165_state *state)
 
 static int si2165_wait_init_done(struct si2165_state *state)
 {
-	int ret = -EINVAL;
+	int ret;
 	u8 val = 0;
 	int i;
 
 	for (i = 0; i < 3; ++i) {
-		si2165_readreg8(state, REG_INIT_DONE, &val);
+		ret = si2165_readreg8(state, REG_INIT_DONE, &val);
+		if (ret < 0)
+			return ret;
 		if (val == 0x01)
 			return 0;
 		usleep_range(1000, 50000);
 	}
 	dev_err(&state->client->dev, "init_done was not set\n");
-	return ret;
+	return -EINVAL;
 }
 
 static int si2165_upload_firmware_block(struct si2165_state *state,
-- 
2.20.1