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Date:   Tue, 26 Mar 2019 13:41:32 +0900
From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     Kangjie Lu <kjlu@umn.edu>
Cc:     pakki001@umn.edu, Colin Ian King <colin.king@canonical.com>,
        Jia-Ju Bai <baijiaju1990@gmail.com>, linux-usb@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH] usb: u132-hcd: fix potential NULL pointer dereference
Message-ID: <20190326044132.GA19677@kroah.com>
References: <20190319135609.GA16254@kroah.com>
 <20190319173407.7279-1-kjlu@umn.edu>
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On Tue, Mar 19, 2019 at 12:34:06PM -0500, Kangjie Lu wrote:
> In case create_singlethread_workqueue fails, the fix notifies
> callers the error to avoid potential NULL pointer dereferences.
> 
> Signed-off-by: Kangjie Lu <kjlu@umn.edu>
> ---
> removed "unlikely"
> ---
>  drivers/usb/host/u132-hcd.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/usb/host/u132-hcd.c b/drivers/usb/host/u132-hcd.c
> index 934584f0a20a..6d5b532b03f8 100644
> --- a/drivers/usb/host/u132-hcd.c
> +++ b/drivers/usb/host/u132-hcd.c
> @@ -3203,6 +3203,8 @@ static int __init u132_hcd_init(void)
>  		return -ENODEV;
>  	printk(KERN_INFO "driver %s\n", hcd_name);
>  	workqueue = create_singlethread_workqueue("u132");
> +	if (!workqueue)
> +		return -ENOMEM;
>  	retval = platform_driver_register(&u132_platform_driver);
>  	return retval;

if platform_driver_register() fails, shouldn't you clean up the
workqueue?  That can be a separate patch, that's not your fault here :)

thanks,

greg k-h