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        Mon, 01 Nov 2021 13:31:34 +0200
Date:   Mon, 1 Nov 2021 13:31:34 +0200
From:   Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To:     Daniel Scally <djrscally@gmail.com>
Cc:     Paul Kocialkowski <paul.kocialkowski@bootlin.com>,
        linux-media@vger.kernel.org, Yong Zhi <yong.zhi@intel.com>,
        Sakari Ailus <sakari.ailus@linux.intel.com>,
        Bingbu Cao <bingbu.cao@intel.com>,
        Tianshu Qiu <tian.shu.qiu@intel.com>,
        Hans de Goede <hdegoede@redhat.com>,
        Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
        Kieran Bingham <kieran.bingham@ideasonboard.com>
Subject: Re: [PATCH v4 16/16] media: i2c: ov8865: Fix lockdep error
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References: <20211101001119.46056-1-djrscally@gmail.com>
 <20211101001119.46056-17-djrscally@gmail.com>
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On Mon, Nov 01, 2021 at 12:11:19AM +0000, Daniel Scally wrote:
> From: Hans de Goede <hdegoede@redhat.com>
> 
> 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:

> [   13.233413] ------------[ cut here ]------------

You may drop this noisy line.

> [   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

Seems to me that this should be moved to the head of the series with Fixes tag
added.

-- 
With Best Regards,
Andy Shevchenko