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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, Nadezda Lutovinova <lutovinova@ispras.ru>,
        Sam Ravnborg <sam@ravnborg.org>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.4 038/214] drm/brige/megachips: Add checking if ge_b850v3_lvds_init() is working correctly
Date:   Tue,  3 Nov 2020 21:34:46 +0100
Message-Id: <20201103203253.650095903@linuxfoundation.org>
In-Reply-To: <20201103203249.448706377@linuxfoundation.org>
References: <20201103203249.448706377@linuxfoundation.org>
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From: Nadezda Lutovinova <lutovinova@ispras.ru>

[ Upstream commit f688a345f0d7a6df4dd2aeca8e4f3c05e123a0ee ]

If ge_b850v3_lvds_init() does not allocate memory for ge_b850v3_lvds_ptr,
then a null pointer dereference is accessed.

The patch adds checking of the return value of ge_b850v3_lvds_init().

Found by Linux Driver Verification project (linuxtesting.org).

Signed-off-by: Nadezda Lutovinova <lutovinova@ispras.ru>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20200819143756.30626-1-lutovinova@ispras.ru
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 .../gpu/drm/bridge/megachips-stdpxxxx-ge-b850v3-fw.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/bridge/megachips-stdpxxxx-ge-b850v3-fw.c b/drivers/gpu/drm/bridge/megachips-stdpxxxx-ge-b850v3-fw.c
index 6e81e5db57f25..b050fd1f3d201 100644
--- a/drivers/gpu/drm/bridge/megachips-stdpxxxx-ge-b850v3-fw.c
+++ b/drivers/gpu/drm/bridge/megachips-stdpxxxx-ge-b850v3-fw.c
@@ -295,8 +295,12 @@ static int stdp4028_ge_b850v3_fw_probe(struct i2c_client *stdp4028_i2c,
 				       const struct i2c_device_id *id)
 {
 	struct device *dev = &stdp4028_i2c->dev;
+	int ret;
+
+	ret = ge_b850v3_lvds_init(dev);
 
-	ge_b850v3_lvds_init(dev);
+	if (ret)
+		return ret;
 
 	ge_b850v3_lvds_ptr->stdp4028_i2c = stdp4028_i2c;
 	i2c_set_clientdata(stdp4028_i2c, ge_b850v3_lvds_ptr);
@@ -354,8 +358,12 @@ static int stdp2690_ge_b850v3_fw_probe(struct i2c_client *stdp2690_i2c,
 				       const struct i2c_device_id *id)
 {
 	struct device *dev = &stdp2690_i2c->dev;
+	int ret;
+
+	ret = ge_b850v3_lvds_init(dev);
 
-	ge_b850v3_lvds_init(dev);
+	if (ret)
+		return ret;
 
 	ge_b850v3_lvds_ptr->stdp2690_i2c = stdp2690_i2c;
 	i2c_set_clientdata(stdp2690_i2c, ge_b850v3_lvds_ptr);
-- 
2.27.0