| Message ID | 20230923103723.10320-1-dinghao.liu@zju.edu.cn (mailing list archive) |
|---|---|
| State | Accepted |
| Headers | show |
| Series | [v3] scsi: zfcp: Fix a double put in zfcp_port_enqueue | expand |
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@zju.edu.cn> > --- > > 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@linux.ibm.com> Martin, can you please pick this directly?
On Sat, 23 Sep 2023 18:37:23 +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(). > > [...] Applied to 6.6/scsi-fixes, thanks! [1/1] scsi: zfcp: Fix a double put in zfcp_port_enqueue https://git.kernel.org/mkp/scsi/c/b481f644d917
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); }
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@zju.edu.cn> --- 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(-)