From: Shay Drory <shayd@xxxxxxxxxxxx>
commit 116a1b9f1cb769b83e5adff323f977a62b1dcb2e upstream.
Currently, when RMPP MADs are processed while the MAD agent is destroyed,
it could result in use after free of rmpp_recv, as decribed below:
cpu-0 cpu-1
----- -----
ib_mad_recv_done()
ib_mad_complete_recv()
ib_process_rmpp_recv_wc()
unregister_mad_agent()
ib_cancel_rmpp_recvs()
cancel_delayed_work()
process_rmpp_data()
start_rmpp()
queue_delayed_work(rmpp_recv->cleanup_work)
destroy_rmpp_recv()
free_rmpp_recv()
cleanup_work()[1]
spin_lock_irqsave(&rmpp_recv->agent->lock) <-- use after free
[1] cleanup_work() == recv_cleanup_handler
Fix it by waiting for the MAD agent reference count becoming zero before
calling to ib_cancel_rmpp_recvs().
Fixes: 9a41e38a467c ("IB/mad: Use IDR for agent IDs")
Link: https://lore.kernel.org/r/20200621104738.54850-2-leon@xxxxxxxxxx
Signed-off-by: Shay Drory <shayd@xxxxxxxxxxxx>
Reviewed-by: Maor Gottlieb <maorg@xxxxxxxxxxxx>
Signed-off-by: Leon Romanovsky <leonro@xxxxxxxxxxxx>
Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/infiniband/core/mad.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/infiniband/core/mad.c b/drivers/infiniband/core/mad.c
index 218411282069b..cd82134d517be 100644
--- a/drivers/infiniband/core/mad.c
+++ b/drivers/infiniband/core/mad.c
@@ -615,10 +615,10 @@ static void unregister_mad_agent(struct ib_mad_agent_private *mad_agent_priv)
idr_unlock(&ib_mad_clients);
flush_workqueue(port_priv->wq);
- ib_cancel_rmpp_recvs(mad_agent_priv);
deref_mad_agent(mad_agent_priv);
wait_for_completion(&mad_agent_priv->comp);
+ ib_cancel_rmpp_recvs(mad_agent_priv);
ib_mad_agent_security_cleanup(&mad_agent_priv->agent);
--
2.25.1
