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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, Stefan Wahren <stefan.wahren@i2se.com>,
        Nicolas Saenz Julienne <nsaenzjulienne@suse.de>,
        Dan Carpenter <dan.carpenter@oracle.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.19 081/639] staging: bcm2835-camera: Abort probe if there is no camera
Date:   Fri, 24 Jan 2020 10:24:11 +0100
Message-Id: <20200124093057.530953361@linuxfoundation.org>
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From: Stefan Wahren <stefan.wahren@i2se.com>

[ Upstream commit 7566f39dfdc11f8a97d5810c6e6295a88f97ef91 ]

Abort the probing of the camera driver in case there isn't a camera
actually connected to the Raspberry Pi. This solution also avoids a
NULL ptr dereference of mmal instance on driver unload.

Fixes: 7b3ad5abf027 ("staging: Import the BCM2835 MMAL-based V4L2 camera driver.")
Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
Reviewed-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Reviewed-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 .../vc04_services/bcm2835-camera/bcm2835-camera.c        | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/staging/vc04_services/bcm2835-camera/bcm2835-camera.c b/drivers/staging/vc04_services/bcm2835-camera/bcm2835-camera.c
index 455082867246d..068e5b9ab2323 100644
--- a/drivers/staging/vc04_services/bcm2835-camera/bcm2835-camera.c
+++ b/drivers/staging/vc04_services/bcm2835-camera/bcm2835-camera.c
@@ -1854,6 +1854,12 @@ static int bcm2835_mmal_probe(struct platform_device *pdev)
 	num_cameras = get_num_cameras(instance,
 				      resolutions,
 				      MAX_BCM2835_CAMERAS);
+
+	if (num_cameras < 1) {
+		ret = -ENODEV;
+		goto cleanup_mmal;
+	}
+
 	if (num_cameras > MAX_BCM2835_CAMERAS)
 		num_cameras = MAX_BCM2835_CAMERAS;
 
@@ -1953,6 +1959,9 @@ cleanup_gdev:
 	pr_info("%s: error %d while loading driver\n",
 		BM2835_MMAL_MODULE_NAME, ret);
 
+cleanup_mmal:
+	vchiq_mmal_finalise(instance);
+
 	return ret;
 }
 
-- 
2.20.1