On Fri, Nov 20, 2020 at 03:48:54PM +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: 86bdf218a717 ("[SCSI] zfcp: cleanup unit sysfs attribute usage")
> Reported-by: Hulk Robot <hulkci@xxxxxxxxxx>
> Signed-off-by: Qinglang Miao <miaoqinglang@xxxxxxxxxx>
> ---
> drivers/s390/scsi/zfcp_unit.c | 2 --
> 1 file changed, 2 deletions(-)
>
> diff --git a/drivers/s390/scsi/zfcp_unit.c b/drivers/s390/scsi/zfcp_unit.c
> index e67bf7388..664b77853 100644
> --- a/drivers/s390/scsi/zfcp_unit.c
> +++ b/drivers/s390/scsi/zfcp_unit.c
> @@ -255,8 +255,6 @@ int zfcp_unit_remove(struct zfcp_port *port, u64 fcp_lun)
> scsi_device_put(sdev);
> }
>
> - put_device(&unit->dev);
> -
> device_unregister(&unit->dev);
>
> return 0;
Same as in the other mail for `zfcp_sysfs_port_remove_store()`. We
explicitly get a new ref in `_zfcp_unit_find()`, so we also need to put
that away again.
--
Best Regards, Benjamin Block / Linux on IBM Z Kernel Development / IBM Systems
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