On Thu, Sep 21, 2023 at 12:21:02PM +0200, Benjamin Block wrote:
> Hello Liu Dinghao,
>
> good find.
Oh, also, please put linux-scsi on the CC list. Patches to zfcp go via
linux-scsi, not linux-s390.
>
> On Thu, Sep 21, 2023 at 02:39:15PM +0800, Dinghao Liu wrote:
> > When device_register() fails, zfcp_port_release() will be called
> > after put_device(). As a result, the zfcp_ccw_adapter_put() after
> > err_out is redundant because it will be called in the call-back
> > function zfcp_port_release(). Remove it from this error path.
>
> So the reference on the adapter object is doubly put, which may
> lead to a premature free of the adapter object itself. Please mention that
> either in the subject, or description; it makes it easier to see what exactly
> breaks at a glance.
>
> >
> > Fixes: f3450c7b9172 ("[SCSI] zfcp: Replace local reference counting with common kref")
> > Signed-off-by: Dinghao Liu <[email protected]>
> > ---
> > drivers/s390/scsi/zfcp_aux.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/s390/scsi/zfcp_aux.c b/drivers/s390/scsi/zfcp_aux.c
> > index df782646e856..489e6239dedf 100644
> > --- a/drivers/s390/scsi/zfcp_aux.c
> > +++ b/drivers/s390/scsi/zfcp_aux.c
> > @@ -552,7 +552,7 @@ struct zfcp_port *zfcp_port_enqueue(struct zfcp_adapter *adapter, u64 wwpn,
> >
> > if (device_register(&port->dev)) {
> > put_device(&port->dev);
> > - goto err_out;
> > + return ERR_PTR(retval);
>
> I'd rather have a new label at the bottom, in front of the return that is
> already there, and jump to that, instead of a different function exit point.
>
> > }
> >
> > write_lock_irq(&adapter->port_list_lock);
> > --
> > 2.17.1
> >
--
Best Regards, Benjamin Block / Linux on IBM Z Kernel Development
IBM Deutschland Research & Development GmbH / https://www.ibm.com/privacy
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> On Thu, Sep 21, 2023 at 12:21:02PM +0200, Benjamin Block wrote:
> > Hello Liu Dinghao,
> >
> > good find.
>
> Oh, also, please put linux-scsi on the CC list. Patches to zfcp go via
> linux-scsi, not linux-s390.
>
> >
> > On Thu, Sep 21, 2023 at 02:39:15PM +0800, Dinghao Liu wrote:
> > > When device_register() fails, zfcp_port_release() will be called
> > > after put_device(). As a result, the zfcp_ccw_adapter_put() after
> > > err_out is redundant because it will be called in the call-back
> > > function zfcp_port_release(). Remove it from this error path.
> >
> > So the reference on the adapter object is doubly put, which may
> > lead to a premature free of the adapter object itself. Please mention that
> > either in the subject, or description; it makes it easier to see what exactly
> > breaks at a glance.
> >
> > >
> > > Fixes: f3450c7b9172 ("[SCSI] zfcp: Replace local reference counting with common kref")
> > > Signed-off-by: Dinghao Liu <[email protected]>
> > > ---
> > > drivers/s390/scsi/zfcp_aux.c | 2 +-
> > > 1 file changed, 1 insertion(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/s390/scsi/zfcp_aux.c b/drivers/s390/scsi/zfcp_aux.c
> > > index df782646e856..489e6239dedf 100644
> > > --- a/drivers/s390/scsi/zfcp_aux.c
> > > +++ b/drivers/s390/scsi/zfcp_aux.c
> > > @@ -552,7 +552,7 @@ struct zfcp_port *zfcp_port_enqueue(struct zfcp_adapter *adapter, u64 wwpn,
> > >
> > > if (device_register(&port->dev)) {
> > > put_device(&port->dev);
> > > - goto err_out;
> > > + return ERR_PTR(retval);
> >
> > I'd rather have a new label at the bottom, in front of the return that is
> > already there, and jump to that, instead of a different function exit point.
> >
> > > }
> > >
> > > write_lock_irq(&adapter->port_list_lock);
> > > --
> > > 2.17.1
> > >
Thank you for your advice! I will resend a new patch soon.
Regards,
Dinghao