RDMA/srpt: Do not register event handler until srpt device is fully setup

Upon rare occasions, KASAN reports a use-after-free Write
in srpt_refresh_port().

This seems to be because an event handler is registered before the
srpt device is fully setup and a race condition upon error may leave a
partially setup event handler in place.

Instead, only register the event handler after srpt device initialization
is complete.

Fixes: a42d985bd5b2 ("ib_srpt: Initial SRP Target merge for v3.3-rc1")
Signed-off-by: William Kucharski <william.kucharski@oracle.com>
Link: https://lore.kernel.org/r/20240202091549.991784-2-william.kucharski@oracle.com
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Leon Romanovsky <leon@kernel.org>

diff --git a/drivers/infiniband/ulp/srpt/ib_srpt.c b/drivers/infiniband/ulp/srpt/ib_srpt.c
index 58f70cf..d35f021 100644 (file)
--- a/drivers/infiniband/ulp/srpt/ib_srpt.c
+++ b/drivers/infiniband/ulp/srpt/ib_srpt.c
@@ -3204,7 +3204,6 @@ static int srpt_add_one(struct ib_device *device)
 
        INIT_IB_EVENT_HANDLER(&sdev->event_handler, sdev->device,
                              srpt_event_handler);
-       ib_register_event_handler(&sdev->event_handler);
 
        for (i = 1; i <= sdev->device->phys_port_cnt; i++) {
                sport = &sdev->port[i - 1];
@@ -3227,6 +3226,7 @@ static int srpt_add_one(struct ib_device *device)
                }
        }
 
+       ib_register_event_handler(&sdev->event_handler);
        spin_lock(&srpt_dev_lock);
        list_add_tail(&sdev->list, &srpt_dev_list);
        spin_unlock(&srpt_dev_lock);
@@ -3237,7 +3237,6 @@ static int srpt_add_one(struct ib_device *device)
 
 err_port:
        srpt_unregister_mad_agent(sdev, i);
-       ib_unregister_event_handler(&sdev->event_handler);
 err_cm:
        if (sdev->cm_id)
                ib_destroy_cm_id(sdev->cm_id);