RDMA/restrack: Increment CQ restrack object before committing

Once the uobj is committed it is immediately possible another thread
could destroy it, which worst case, can result in a use-after-free
of the restrack objects.

Cc: syzkaller <syzkaller@googlegroups.com>
Fixes: 08f294a1524b ("RDMA/core: Add resource tracking for create and destroy CQs")
Reported-by: Noa Osherovich <noaos@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

diff --git a/drivers/infiniband/core/uverbs_cmd.c b/drivers/infiniband/core/uverbs_cmd.c
index 256934d..4e55f83 100644 (file)
--- a/drivers/infiniband/core/uverbs_cmd.c
+++ b/drivers/infiniband/core/uverbs_cmd.c
@@ -1030,14 +1030,14 @@ static struct ib_ucq_object *create_cq(struct ib_uverbs_file *file,
        resp.response_length = offsetof(typeof(resp), response_length) +
                sizeof(resp.response_length);
 
+       cq->res.type = RDMA_RESTRACK_CQ;
+       rdma_restrack_add(&cq->res);
+
        ret = cb(file, obj, &resp, ucore, context);
        if (ret)
                goto err_cb;
 
        uobj_alloc_commit(&obj->uobject);
-       cq->res.type = RDMA_RESTRACK_CQ;
-       rdma_restrack_add(&cq->res);
-
        return obj;
 
 err_cb: