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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, Hans de Goede <hdegoede@redhat.com>,
        Sakari Ailus <sakari.ailus@linux.intel.com>,
        Mauro Carvalho Chehab <mchehab+huawei@kernel.org>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.16 0187/1039] media: i2c: ov8865: Fix lockdep error
Date:   Mon, 24 Jan 2022 19:32:56 +0100
Message-Id: <20220124184131.586323555@linuxfoundation.org>
In-Reply-To: <20220124184125.121143506@linuxfoundation.org>
References: <20220124184125.121143506@linuxfoundation.org>
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From: Hans de Goede <hdegoede@redhat.com>

[ Upstream commit 6e1c9bc9ae96e57bcd8807174f2c0f44f9ef7938 ]

ov8865_state_init() calls ov8865_state_mipi_configure() which uses
__v4l2_ctrl_s_ctrl[_int64](). This means that sensor->mutex (which
is also sensor->ctrls.handler.lock) must be locked before calling
ov8865_state_init().

Note ov8865_state_mipi_configure() is also used in other places where
the lock is already held so it cannot be changed itself.

This fixes the following lockdep kernel WARN:

[   13.233421] WARNING: CPU: 0 PID: 8 at drivers/media/v4l2-core/v4l2-ctrls-api.c:833 __v4l2_ctrl_s_ctrl+0x4d/0x60 [videodev]
...
[   13.234063] Call Trace:
[   13.234074]  ov8865_state_configure+0x98b/0xc00 [ov8865]
[   13.234095]  ov8865_probe+0x4b1/0x54c [ov8865]
[   13.234117]  i2c_device_probe+0x13c/0x2d0

Fixes: 11c0d8fdccc5 ("media: i2c: Add support for the OV8865 image sensor")
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/media/i2c/ov8865.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/drivers/media/i2c/ov8865.c
+++ b/drivers/media/i2c/ov8865.c
@@ -2893,7 +2893,9 @@ static int ov8865_probe(struct i2c_clien
 	if (ret)
 		goto error_mutex;
 
+	mutex_lock(&sensor->mutex);
 	ret = ov8865_state_init(sensor);
+	mutex_unlock(&sensor->mutex);
 	if (ret)
 		goto error_ctrls;