[PATCH 6.8 558/715] RDMA/srpt: Do not register event handler until srpt device is fully setup

[Sasha Levin]

From: William Kucharski <william.kucharski@xxxxxxxxxx>

[ Upstream commit c21a8870c98611e8f892511825c9607f1e2cd456 ]

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@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20240202091549.991784-2-william.kucharski@xxxxxxxxxx
Reviewed-by: Bart Van Assche <bvanassche@xxxxxxx>
Signed-off-by: Leon Romanovsky <leon@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/infiniband/ulp/srpt/ib_srpt.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/infiniband/ulp/srpt/ib_srpt.c b/drivers/infiniband/ulp/srpt/ib_srpt.c
index 040234c01be4d..9632afbd727b6 100644
--- a/drivers/infiniband/ulp/srpt/ib_srpt.c
+++ b/drivers/infiniband/ulp/srpt/ib_srpt.c
@@ -3209,7 +3209,6 @@ 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];
@@ -3232,6 +3231,7 @@ 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);
@@ -3242,7 +3242,6 @@ 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);
-- 
2.43.0