On Fri, Nov 20, 2020 at 03:48:53PM +0800, Qinglang Miao wrote:
> kfree(port) is called in put_device(&port->dev) so that following
> use would cause use-after-free bug.
>
> the former put_device is redundant for device_unregister contains
> put_device already. So just remove it to fix this.
>
> Fixes: 83d4e1c33d93 ("[SCSI] zfcp: cleanup port sysfs attribute usage")
> Reported-by: Hulk Robot <hulkci@xxxxxxxxxx>
> Signed-off-by: Qinglang Miao <miaoqinglang@xxxxxxxxxx>
> ---
> drivers/s390/scsi/zfcp_sysfs.c | 2 --
> 1 file changed, 2 deletions(-)
>
> diff --git a/drivers/s390/scsi/zfcp_sysfs.c b/drivers/s390/scsi/zfcp_sysfs.c
> index 8d9662e8b..06285e452 100644
> --- a/drivers/s390/scsi/zfcp_sysfs.c
> +++ b/drivers/s390/scsi/zfcp_sysfs.c
> @@ -327,8 +327,6 @@ static ssize_t zfcp_sysfs_port_remove_store(struct device *dev,
> list_del(&port->list);
> write_unlock_irq(&adapter->port_list_lock);
>
> - put_device(&port->dev);
> -
> zfcp_erp_port_shutdown(port, 0, "syprs_1");
> device_unregister(&port->dev);
> out:
Hmm, the placement of the put_device() is indeed strange, now that I
think about it. But just removing it and then having a dangling
reference also seems wrong - we do get one explicitly in
`zfcp_get_port_by_wwpn()`.
My first thought would be to move it after the `device_unregister()`
call, and before the `out:` label.
--
Best Regards, Benjamin Block / Linux on IBM Z Kernel Development / IBM Systems
IBM Deutschland Research & Development GmbH / https://www.ibm.com/privacy
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