linux-kernel - Re: [PATCH] driver core: Make sure device detached from driver before deleting it

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <1742035.QldI8RN9SY@aspire.rjw.lan>
Date:   Wed, 18 Oct 2017 12:04:18 +0200
From:   "Rafael J. Wysocki" <rjw@...ysocki.net>
To:     Jeffy Chen <jeffy.chen@...k-chips.com>
Cc:     linux-kernel@...r.kernel.org, dmitry.torokhov@...il.com,
        heiko@...ech.de, briannorris@...omium.org, dianders@...omium.org,
        tfiga@...omium.org, broonie@...nel.org, seanpaul@...omium.org,
        thierry.reding@...il.com,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Subject: Re: [PATCH] driver core: Make sure device detached from driver before deleting it

On Wednesday, October 18, 2017 7:49:26 AM CEST Jeffy Chen wrote:
> There are cases we call device_del() without detaching it from the
> driver(e.g. spi core del children devices).

But device_del() itself detaches the device from its driver.

> Signed-off-by: Jeffy Chen <jeffy.chen@...k-chips.com>
> ---
> 
>  drivers/base/core.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/base/core.c b/drivers/base/core.c
> index 12ebd055724c..717efc3020af 100644
> --- a/drivers/base/core.c
> +++ b/drivers/base/core.c
> @@ -1951,6 +1951,8 @@ void device_del(struct device *dev)
>  	struct kobject *glue_dir = NULL;
>  	struct class_interface *class_intf;
>  
> +	device_release_driver(dev);
> +
>  	/* Notify clients of device removal.  This call must come
>  	 * before dpm_sysfs_remove().
>  	 */
> 

But device_del() calls bus_remove_device() which in turn calls
device_release_driver(), so this looks like an ordering issue to me.

What *exactly* is not working?  Or rather, what symptoms do you see?

Thanks,
Rafael