On Sat, Sep 23, 2023 at 06:37:23PM +0800, Dinghao Liu wrote:
> When device_register() fails, zfcp_port_release() will be called
> after put_device(). As a result, zfcp_ccw_adapter_put() will be
> called twice: one in zfcp_port_release() and one in the error path
> after device_register(). So the reference on the adapter object is
> doubly put, which may lead to a premature free. Fix this by adjusting
> the error tag after device_register().
>
> Fixes: f3450c7b9172 ("[SCSI] zfcp: Replace local reference counting with common kref")
> Signed-off-by: Dinghao Liu <dinghao.liu@xxxxxxxxxx>
> ---
>
> Changelog:
>
> v2: -Improve the patch description.
> -Add a new label 'err_register' to unify code style.
>
> v3: -Improve the names of goto labels.
> ---
> drivers/s390/scsi/zfcp_aux.c | 9 +++++----
> 1 file changed, 5 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/s390/scsi/zfcp_aux.c b/drivers/s390/scsi/zfcp_aux.c
> index df782646e856..ab2f35bc294d 100644
> --- a/drivers/s390/scsi/zfcp_aux.c
> +++ b/drivers/s390/scsi/zfcp_aux.c
> @@ -518,12 +518,12 @@ struct zfcp_port *zfcp_port_enqueue(struct zfcp_adapter *adapter, u64 wwpn,
> if (port) {
> put_device(&port->dev);
> retval = -EEXIST;
> - goto err_out;
> + goto err_put;
> }
>
> port = kzalloc(sizeof(struct zfcp_port), GFP_KERNEL);
> if (!port)
> - goto err_out;
> + goto err_put;
>
> rwlock_init(&port->unit_list_lock);
> INIT_LIST_HEAD(&port->unit_list);
> @@ -546,7 +546,7 @@ struct zfcp_port *zfcp_port_enqueue(struct zfcp_adapter *adapter, u64 wwpn,
>
> if (dev_set_name(&port->dev, "0x%016llx", (unsigned long long)wwpn)) {
> kfree(port);
> - goto err_out;
> + goto err_put;
> }
> retval = -EINVAL;
>
> @@ -563,7 +563,8 @@ struct zfcp_port *zfcp_port_enqueue(struct zfcp_adapter *adapter, u64 wwpn,
>
> return port;
>
> -err_out:
> +err_put:
> zfcp_ccw_adapter_put(adapter);
> +err_out:
> return ERR_PTR(retval);
> }
> --
> 2.17.1
>
Looks good to me. Ideally we would have a stable tag (v2.6.33+) in with the
Fixes tag as well, but I don't think we need to fly an extra round just for
that. We can ask the stable team once this is included upstream.
Acked-by: Benjamin Block <bblock@xxxxxxxxxxxxx>
Martin, can you please pick this directly?
--
Best Regards, Benjamin Block / Linux on IBM Z Kernel Development
IBM Deutschland Research & Development GmbH / https://www.ibm.com/privacy
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