[PATCH rdma-next] RDMA/restrack: Delay QP deletion till all users are gone

[Leon Romanovsky <leon@kernel.org>]

From: Shay Drory <shayd@nvidia.com>

Currently, in case of QP, the following use-after-free is possible:

	cpu0				cpu1
	----				----
 res_get_common_dumpit()
 rdma_restrack_get()
 fill_res_qp_entry()
				ib_destroy_qp_user()
				 rdma_restrack_del()
				 qp->device->ops.destroy_qp()
  ib_query_qp()
  qp->device->ops.query_qp()
    --> use-after-free-qp

This is because rdma_restrack_del(), in case of QP, isn't waiting until
all users are gone.

Fix it by making rdma_restrack_del() wait until all users are gone for
QPs as well.

Fixes: 13ef5539def7 ("RDMA/restrack: Count references to the verbs objects")
Signed-off-by: Shay Drory <shayd@nvidia.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
---
 drivers/infiniband/core/restrack.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/infiniband/core/restrack.c b/drivers/infiniband/core/restrack.c
index ffabaf327242..def0c5b0efe9 100644
--- a/drivers/infiniband/core/restrack.c
+++ b/drivers/infiniband/core/restrack.c
@@ -340,7 +340,7 @@ void rdma_restrack_del(struct rdma_restrack_entry *res)
 	rt = &dev->res[res->type];
 
 	old = xa_erase(&rt->xa, res->id);
-	if (res->type == RDMA_RESTRACK_MR || res->type == RDMA_RESTRACK_QP)
+	if (res->type == RDMA_RESTRACK_MR)
 		return;
 	WARN_ON(old != res);
 
-- 
2.30.2