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From:   "Rafael J. Wysocki" <rafael@kernel.org>
Date:   Thu, 13 Dec 2018 10:38:14 +0100
Message-ID: <CAJZ5v0jkE=Rt2ozwcTxRdUN++Sr4HXULksDeMx4jEWj1jVDcyA@mail.gmail.com>
Subject: Re: [PATCH] drivers/base: use a worker for sysfs unbind
To:     Daniel Vetter <daniel.vetter@ffwll.ch>
Cc:     Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        dri-devel <dri-devel@lists.freedesktop.org>,
        ramalingam.c@intel.com,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        "Rafael J. Wysocki" <rafael@kernel.org>,
        Daniel Vetter <daniel.vetter@intel.com>
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On Mon, Dec 10, 2018 at 9:47 AM Daniel Vetter <daniel.vetter@ffwll.ch> wrote:
>
> Drivers might want to remove some sysfs files, which needs the same
> locks and ends up angering lockdep. Relevant snippet of the stack
> trace:
>
>   kernfs_remove_by_name_ns+0x3b/0x80
>   bus_remove_driver+0x92/0xa0
>   acpi_video_unregister+0x24/0x40
>   i915_driver_unload+0x42/0x130 [i915]
>   i915_pci_remove+0x19/0x30 [i915]
>   pci_device_remove+0x36/0xb0
>   device_release_driver_internal+0x185/0x250
>   unbind_store+0xaf/0x180
>   kernfs_fop_write+0x104/0x190

Is the acpi_bus_unregister_driver() in acpi_video_unregister() the
source of the lockdep unhappiness?