linux-kernel - Re: [PATCH v2] Drivers: hv: vmbus: Fix memory leak in vmbus_add_channel

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Message-ID: <20220206145556.72obb2qxbsktw3sc@surface>
Date:   Sun, 6 Feb 2022 06:55:56 -0800
From:   Juan Vazquez <juvazq@...ux.microsoft.com>
To:     Miaoqian Lin <linmq006@...il.com>
Cc:     decui@...rosoft.com, gregkh@...uxfoundation.org,
        haiyangz@...rosoft.com, kys@...rosoft.com,
        linux-hyperv@...r.kernel.org, linux-kernel@...r.kernel.org,
        sthemmin@...rosoft.com, wei.liu@...nel.org
Subject: Re: [PATCH v2] Drivers: hv: vmbus: Fix memory leak in
 vmbus_add_channel_kobj

On Fri, Feb 04, 2022 at 01:30:08AM +0800, Miaoqian Lin wrote:
> kobject_init_and_add() takes reference even when it fails.
> According to the doc of kobject_init_and_add()：
> 
>    If this function returns an error, kobject_put() must be called to
>    properly clean up the memory associated with the object.
> 
> Fix memory leak by calling kobject_put().
> 
> Fixes: c2e5df616e1a ("vmbus: add per-channel sysfs info")
> Signed-off-by: Miaoqian Lin <linmq006@...il.com>
> ---
> Changes in v2:
> - Add cleanup when sysfs_create_group() fails
> 
> kobject_uevent() is used for notifying userspace by sending an uevent,
> I don't think we need to do error handling for it.

Thanks for the patch. It looks good to me.

Reviewed-by: Juan Vazquez <juvazq@...ux.microsoft.com>

> ---
>  drivers/hv/vmbus_drv.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
> index 17bf55fe3169..34a4fd21bdf5 100644
> --- a/drivers/hv/vmbus_drv.c
> +++ b/drivers/hv/vmbus_drv.c
> @@ -2028,8 +2028,10 @@ int vmbus_add_channel_kobj(struct hv_device *dev, struct vmbus_channel *channel)
>  	kobj->kset = dev->channels_kset;
>  	ret = kobject_init_and_add(kobj, &vmbus_chan_ktype, NULL,
>  				   "%u", relid);
> -	if (ret)
> +	if (ret) {
> +		kobject_put(kobj);
>  		return ret;
> +	}
>  
>  	ret = sysfs_create_group(kobj, &vmbus_chan_group);
>  
> @@ -2038,6 +2040,7 @@ int vmbus_add_channel_kobj(struct hv_device *dev, struct vmbus_channel *channel)
>  		 * The calling functions' error handling paths will cleanup the
>  		 * empty channel directory.
>  		 */
> +		kobject_put(kobj);
>  		dev_err(device, "Unable to set up channel sysfs files\n");
>  		return ret;
>  	}
> -- 
> 2.25.1