linux-kernel - Re: [char-misc-next v2] mei: bus: fix device leak

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Message-ID: <2025062458-sadness-pregnancy-94b6@gregkh>
Date: Tue, 24 Jun 2025 12:35:12 +0100
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: Alexander Usyskin <alexander.usyskin@...el.com>
Cc: Reuven Abliyev <reuven.abliyev@...el.com>, linux-kernel@...r.kernel.org
Subject: Re: [char-misc-next v2] mei: bus: fix device leak

On Tue, Jun 24, 2025 at 02:05:20PM +0300, Alexander Usyskin wrote:
> The bus rescan function creates bus devices for all clients.
> The fixup routine is executed on all devices, unneeded
> devices are removed and fully initialized once set
> is_added flag to 1.
> 
> If link to firmware is reset right after all devices are
> initialized, but before fixup is executed, the rescan tries
> to remove devices.
> The is_added flag is not set and the mei_cl_bus_dev_destroy
> returns prematurely.
> Allow to clean up device when is_added flag is unset to
> account for above scenario.
> 
> Fixes: 6009595a66e4 ("mei: bus: link client devices instead of host clients")
> Signed-off-by: Alexander Usyskin <alexander.usyskin@...el.com>
> ---
>  drivers/misc/mei/bus.c | 11 ++++-------
>  1 file changed, 4 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/misc/mei/bus.c b/drivers/misc/mei/bus.c
> index 67176caf5416..f2e5d550c6b4 100644
> --- a/drivers/misc/mei/bus.c
> +++ b/drivers/misc/mei/bus.c
> @@ -1430,17 +1430,14 @@ static void mei_cl_bus_dev_stop(struct mei_cl_device *cldev)
>   */
>  static void mei_cl_bus_dev_destroy(struct mei_cl_device *cldev)
>  {
> -
>  	WARN_ON(!mutex_is_locked(&cldev->bus->cl_bus_lock));
>  
> -	if (!cldev->is_added)
> -		return;
> -
> -	device_del(&cldev->dev);
> +	if (cldev->is_added) {
> +		device_del(&cldev->dev);
> +		cldev->is_added = 0;
> +	}
>  
>  	list_del_init(&cldev->bus_list);
> -
> -	cldev->is_added = 0;
>  	put_device(&cldev->dev);
>  }
>  
> -- 
> 2.43.0
> 

Hi,

This is the friendly patch-bot of Greg Kroah-Hartman.  You have sent him
a patch that has triggered this response.  He used to manually respond
to these common problems, but in order to save his sanity (he kept
writing the same thing over and over, yet to different people), I was
created.  Hopefully you will not take offence and will fix the problem
in your patch and resubmit it so that it can be accepted into the Linux
kernel tree.

You are receiving this message because of the following common error(s)
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If you wish to discuss this problem further, or you have questions about
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thanks,

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