[PATCH v2 net] net/mlx5: DR, prevent potential error pointer dereference

[Dan Carpenter <dan.carpenter@linaro.org>]

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: Yevgeny Kliteynik <kliteyn@nvidia.com>
---
v2: Fix a typo in the commit message.  "generally".

 .../net/ethernet/mellanox/mlx5/core/steering/sws/dr_domain.c    | 2 ++
 1 file changed, 2 insertions(+)

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 3d74109f8230..a379e8358f82 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/steering/sws/dr_domain.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/steering/sws/dr_domain.c
@@ -297,6 +297,8 @@ 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);
+		if (ret != -EBUSY)
+			return NULL;
 		return ERR_PTR(ret);
 	}
 
-- 
2.45.2