net/mlx5: DR, prevent potential error pointer dereference

The dr_domain_add_vport_cap() function generally returns NULL on error
but sometimes we want it to return ERR_PTR(-EBUSY) so the caller can
retry.  The problem here is that "ret" can be either -EBUSY or -ENOMEM
and if it's and -ENOMEM then the error pointer is propogated back and
eventually dereferenced in dr_ste_v0_build_src_gvmi_qpn_tag().

Fixes: 11a45def2e19 ("net/mlx5: DR, Add support for SF vports")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Link: https://patch.msgid.link/07477254-e179-43e2-b1b3-3b9db4674195@stanley.mountain
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/steering/sws/dr_domain.c b/drivers/net/ethernet/mellanox/mlx5/core/steering/sws/dr_domain.c
index 3d74109f82300ee2256a92d047ce3e429b6343a0..49f22cad92bfd0fcd05f2d55654ad5cd64bafbc8 100644 (file)
--- a/drivers/net/ethernet/mellanox/mlx5/core/steering/sws/dr_domain.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/steering/sws/dr_domain.c
@@ -297,7 +297,9 @@ dr_domain_add_vport_cap(struct mlx5dr_domain *dmn, u16 vport)
        if (ret) {
                mlx5dr_dbg(dmn, "Couldn't insert new vport into xarray (%d)\n", ret);
                kvfree(vport_caps);
-               return ERR_PTR(ret);
+               if (ret == -EBUSY)
+                       return ERR_PTR(-EBUSY);
+               return NULL;
        }
 
        return vport_caps;