Re: [PATCH 1/4] RDMA/cm: Fix memory leak in cm_add/remove_one

Leon Romanovsky
2019-09-18T11:36:27Z

On Mon, Sep 16, 2019 at 06:45:48PM +0000, Jason Gunthorpe wrote:
> On Mon, Sep 16, 2019 at 10:11:51AM +0300, Leon Romanovsky wrote:
> > From: Jack Morgenstein <jackm@dev.mellanox.co.il>
> >
> > In the process of moving the debug counters sysfs entries, the commit
> > mentioned below eliminated the cm_infiniband sysfs directory.
> >
> > This sysfs directory was tied to the cm_port object allocated in procedure
> > cm_add_one().
> >
> > Before the commit below, this cm_port object was freed via a call to
> > kobject_put(port->kobj) in procedure cm_remove_port_fs().
> >
> > Since port no longer uses its kobj, kobject_put(port->kobj) was eliminated.
> > This, however, meant that kfree was never called for the cm_port buffers.
> >
> > Fix this by adding explicit kfree(port) calls to functions cm_add_one()
> > and cm_remove_one().
> >
> > Note: the kfree call in the first chunk below (in the cm_add_one error
> > flow) fixes an old, undetected memory leak.
> >
> > Fixes: c87e65cfb97c ("RDMA/cm: Move debug counters to be under relevant IB device")
> > Signed-off-by: Jack Morgenstein <jackm@dev.mellanox.co.il>
> > Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
> > drivers/infiniband/core/cm.c | 3 +++
> > 1 file changed, 3 insertions(+)
> >
> > diff --git a/drivers/infiniband/core/cm.c b/drivers/infiniband/core/cm.c
> > index da10e6ccb43c..5920c0085d35 100644
> > +++ b/drivers/infiniband/core/cm.c
> > @@ -4399,6 +4399,7 @@ static void cm_add_one(struct ib_device *ib_device)
> > error1:
> > port_modify.set_port_cap_mask = 0;
> > port_modify.clr_port_cap_mask = IB_PORT_CM_SUP;
> > + kfree(port);
> > while (--i) {
> > if (!rdma_cap_ib_cm(ib_device, i))
> > continue;
> > @@ -4407,6 +4408,7 @@ static void cm_add_one(struct ib_device *ib_device)
> > ib_modify_port(ib_device, port->port_num, 0, &port_modify);
> > ib_unregister_mad_agent(port->mad_agent);
> > cm_remove_port_fs(port);
> > + kfree(port);
> > }
> > free:
> > kfree(cm_dev);
> > @@ -4460,6 +4462,7 @@ static void cm_remove_one(struct ib_device *ib_device, void *client_data)
> > spin_unlock_irq(&cm.state_lock);
> > ib_unregister_mad_agent(cur_mad_agent);
> > cm_remove_port_fs(port);
> > + kfree(port);
> > }
>
> This whole thing is looking pretty goofy now, and I suspect there are
> more error unwind bugs here.
>
> How about this instead:

It looks OK to me.

Thanks

>
> From e8dad20c7b69436e63b18f16cd9457ea27da5bc1 Mon Sep 17 00:00:00 2001
> From: Jack Morgenstein <jackm@dev.mellanox.co.il>
> Date: Mon, 16 Sep 2019 10:11:51 +0300
> Subject: [PATCH] RDMA/cm: Fix memory leak in cm_add/remove_one
>
> In the process of moving the debug counters sysfs entries, the commit
> mentioned below eliminated the cm_infiniband sysfs directory, and created
> some missing cases where the port pointers were not being freed as the
> kobject_put was also eliminated.
>
> Rework this to not allocate port pointers and consolidate all the error
> unwind into one sequence.
>
> This also fixes unlikely racey bugs where error-unwind after unregistering
> the MAD handler would miss flushing the WQ and other clean up that is
> necessary once concurrency starts.
>
> Fixes: c87e65cfb97c ("RDMA/cm: Move debug counters to be under relevant IB device")
> Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
> ---
> drivers/infiniband/core/cm.c | 187 ++++++++++++++++++-----------------
> 1 file changed, 94 insertions(+), 93 deletions(-)
>
> diff --git a/drivers/infiniband/core/cm.c b/drivers/infiniband/core/cm.c
> index da10e6ccb43cd0..30a764e763dec1 100644
> --- a/drivers/infiniband/core/cm.c
> +++ b/drivers/infiniband/core/cm.c
> @@ -223,7 +223,7 @@ struct cm_device {
> struct ib_device *ib_device;
> u8 ack_delay;
> int going_down;
> - struct cm_port *port[0];
> + struct cm_port port[];
> };
>
> struct cm_av {
> @@ -520,7 +520,7 @@ get_cm_port_from_path(struct sa_path_rec *path, const struct ib_gid_attr *attr)
> read_lock_irqsave(&cm.device_lock, flags);
> list_for_each_entry(cm_dev, &cm.device_list, list) {
> if (cm_dev->ib_device == attr->device) {
> - port = cm_dev->port[attr->port_num - 1];
> + port = &cm_dev->port[attr->port_num - 1];
> break;
> }
> }
> @@ -539,7 +539,7 @@ get_cm_port_from_path(struct sa_path_rec *path, const struct ib_gid_attr *attr)
> sa_conv_pathrec_to_gid_type(path),
> NULL);
> if (!IS_ERR(attr)) {
> - port = cm_dev->port[attr->port_num - 1];
> + port = &cm_dev->port[attr->port_num - 1];
> break;
> }
> }
> @@ -4319,23 +4319,99 @@ static void cm_remove_port_fs(struct cm_port *port)
>
> }
>
> -static void cm_add_one(struct ib_device *ib_device)
> +static void cm_destroy_one_port(struct cm_device *cm_dev, unsigned int port_num)
> {
> - struct cm_device *cm_dev;
> - struct cm_port *port;
> + struct cm_port *port = &cm_dev->port[port_num - 1];
> + struct ib_port_modify port_modify = {
> + .clr_port_cap_mask = IB_PORT_CM_SUP
> + };
> + struct ib_mad_agent *cur_mad_agent;
> + struct cm_id_private *cm_id_priv;
> +
> + if (!rdma_cap_ib_cm(cm_dev->ib_device, port_num))
> + return;
> +
> + ib_modify_port(cm_dev->ib_device, port_num, 0, &port_modify);
> +
> + /* Mark all the cm_id's as not valid */
> + spin_lock_irq(&cm.lock);
> + list_for_each_entry (cm_id_priv, &port->cm_priv_altr_list, altr_list)
> + cm_id_priv->altr_send_port_not_ready = 1;
> + list_for_each_entry (cm_id_priv, &port->cm_priv_prim_list, prim_list)
> + cm_id_priv->prim_send_port_not_ready = 1;
> + spin_unlock_irq(&cm.lock);
> +
> + /*
> + * We flush the queue here after the going_down set, this verifies
> + * that no new works will be queued in the recv handler, after that we
> + * can call the unregister_mad_agent
> + */
> + flush_workqueue(cm.wq);
> +
> + spin_lock_irq(&cm.state_lock);
> + cur_mad_agent = port->mad_agent;
> + port->mad_agent = NULL;
> + spin_unlock_irq(&cm.state_lock);
> +
> + if (cur_mad_agent)
> + ib_unregister_mad_agent(cur_mad_agent);
> +
> + cm_remove_port_fs(port);
> +}
> +
> +static int cm_init_one_port(struct cm_device *cm_dev, unsigned int port_num)
> +{
> + struct cm_port *port = &cm_dev->port[port_num - 1];
> struct ib_mad_reg_req reg_req = {
> .mgmt_class = IB_MGMT_CLASS_CM,
> .mgmt_class_version = IB_CM_CLASS_VERSION,
> };
> struct ib_port_modify port_modify = {
> - .set_port_cap_mask = IB_PORT_CM_SUP
> + .set_port_cap_mask = IB_PORT_CM_SUP,
> };
> - unsigned long flags;
> int ret;
> +
> + if (!rdma_cap_ib_cm(cm_dev->ib_device, port_num))
> + return 0;
> +
> + set_bit(IB_MGMT_METHOD_SEND, reg_req.method_mask);
> +
> + port->cm_dev = cm_dev;
> + port->port_num = port_num;
> +
> + INIT_LIST_HEAD(&port->cm_priv_prim_list);
> + INIT_LIST_HEAD(&port->cm_priv_altr_list);
> +
> + ret = cm_create_port_fs(port);
> + if (ret)
> + return ret;
> +
> + port->mad_agent =
> + ib_register_mad_agent(cm_dev->ib_device, port_num, IB_QPT_GSI,
> + &reg_req, 0, cm_send_handler,
> + cm_recv_handler, port, 0);
> + if (IS_ERR(port->mad_agent)) {
> + cm_destroy_one_port(cm_dev, port_num);
> + return PTR_ERR(port->mad_agent);
> + }
> +
> + ret = ib_modify_port(cm_dev->ib_device, port_num, 0, &port_modify);
> + if (ret) {
> + cm_destroy_one_port(cm_dev, port_num);
> + return ret;
> + }
> +
> + return 0;
> +}
> +
> +static void cm_add_one(struct ib_device *ib_device)
> +{
> + struct cm_device *cm_dev;
> + unsigned long flags;
> int count = 0;
> u8 i;
>
> - cm_dev = kzalloc(struct_size(cm_dev, port, ib_device->phys_port_cnt),
> + cm_dev = kvzalloc(struct_size(cm_dev, port, ib_device->phys_port_cnt),
> GFP_KERNEL);
> if (!cm_dev)
> return;
> @@ -4344,41 +4420,9 @@ static void cm_add_one(struct ib_device *ib_device)
> cm_dev->ack_delay = ib_device->attrs.local_ca_ack_delay;
> cm_dev->going_down = 0;
>
> - set_bit(IB_MGMT_METHOD_SEND, reg_req.method_mask);
> for (i = 1; i <= ib_device->phys_port_cnt; i++) {
> - if (!rdma_cap_ib_cm(ib_device, i))
> - continue;
> -
> - port = kzalloc(sizeof *port, GFP_KERNEL);
> - if (!port)
> - goto error1;
> -
> - cm_dev->port[i-1] = port;
> - port->cm_dev = cm_dev;
> - port->port_num = i;
> -
> - INIT_LIST_HEAD(&port->cm_priv_prim_list);
> - INIT_LIST_HEAD(&port->cm_priv_altr_list);
> -
> - ret = cm_create_port_fs(port);
> - if (ret)
> - goto error1;
> -
> - port->mad_agent = ib_register_mad_agent(ib_device, i,
> - IB_QPT_GSI,
> - &reg_req,
> - 0,
> - cm_send_handler,
> - cm_recv_handler,
> - port,
> - 0);
> - if (IS_ERR(port->mad_agent))
> - goto error2;
> -
> - ret = ib_modify_port(ib_device, i, 0, &port_modify);
> - if (ret)
> - goto error3;
> -
> + if (!cm_init_one_port(cm_dev, i))
> + goto error;
> count++;
> }
>
> @@ -4392,35 +4436,16 @@ static void cm_add_one(struct ib_device *ib_device)
> write_unlock_irqrestore(&cm.device_lock, flags);
> return;
>
> -error3:
> - ib_unregister_mad_agent(port->mad_agent);
> -error2:
> - cm_remove_port_fs(port);
> -error1:
> - port_modify.set_port_cap_mask = 0;
> - port_modify.clr_port_cap_mask = IB_PORT_CM_SUP;
> - while (--i) {
> - if (!rdma_cap_ib_cm(ib_device, i))
> - continue;
> -
> - port = cm_dev->port[i-1];
> - ib_modify_port(ib_device, port->port_num, 0, &port_modify);
> - ib_unregister_mad_agent(port->mad_agent);
> - cm_remove_port_fs(port);
> - }
> +error:
> + while (--i)
> + cm_destroy_one_port(cm_dev, i);
> free:
> - kfree(cm_dev);
> + kvfree(cm_dev);
> }
>
> static void cm_remove_one(struct ib_device *ib_device, void *client_data)
> {
> struct cm_device *cm_dev = client_data;
> - struct cm_port *port;
> - struct cm_id_private *cm_id_priv;
> - struct ib_mad_agent *cur_mad_agent;
> - struct ib_port_modify port_modify = {
> - .clr_port_cap_mask = IB_PORT_CM_SUP
> - };
> unsigned long flags;
> int i;
>
> @@ -4435,34 +4460,10 @@ static void cm_remove_one(struct ib_device *ib_device, void *client_data)
> cm_dev->going_down = 1;
> spin_unlock_irq(&cm.lock);
>
> - for (i = 1; i <= ib_device->phys_port_cnt; i++) {
> - if (!rdma_cap_ib_cm(ib_device, i))
> - continue;
> -
> - port = cm_dev->port[i-1];
> - ib_modify_port(ib_device, port->port_num, 0, &port_modify);
> - /* Mark all the cm_id's as not valid */
> - spin_lock_irq(&cm.lock);
> - list_for_each_entry(cm_id_priv, &port->cm_priv_altr_list, altr_list)
> - cm_id_priv->altr_send_port_not_ready = 1;
> - list_for_each_entry(cm_id_priv, &port->cm_priv_prim_list, prim_list)
> - cm_id_priv->prim_send_port_not_ready = 1;
> - spin_unlock_irq(&cm.lock);
> - /*
> - * We flush the queue here after the going_down set, this
> - * verify that no new works will be queued in the recv handler,
> - * after that we can call the unregister_mad_agent
> - */
> - flush_workqueue(cm.wq);
> - spin_lock_irq(&cm.state_lock);
> - cur_mad_agent = port->mad_agent;
> - port->mad_agent = NULL;
> - spin_unlock_irq(&cm.state_lock);
> - ib_unregister_mad_agent(cur_mad_agent);
> - cm_remove_port_fs(port);
> - }
> + for (i = 1; i <= ib_device->phys_port_cnt; i++)
> + cm_destroy_one_port(cm_dev, i);
>
> - kfree(cm_dev);
> + kvfree(cm_dev);
> }
>
> static int __init ib_cm_init(void)
> --
> 2.23.0
>