From: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Date: Mon, 7 Mar 2022 18:47:39 +0100
Subject: ice: fix NULL pointer dereference in ice_update_vsi_tx_ring_stats()
Patch-mainline: v5.17
Git-commit: f153546913bada41a811722f2c6d17c3243a0333
References: jsc#SLE-18375

It is possible to do NULL pointer dereference in routine that updates
Tx ring stats. Currently only stats and bytes are updated when ring
pointer is valid, but later on ring is accessed to propagate gathered Tx
stats onto VSI stats.

Change the existing logic to move to next ring when ring is NULL.

Fixes: e72bba21355d ("ice: split ice_ring onto Tx/Rx separate structs")
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Acked-by: Alexander Lobakin <alexandr.lobakin@intel.com>
Tested-by: Gurucharan G <gurucharanx.g@intel.com> (A Contingent worker at Intel)
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/net/ethernet/intel/ice/ice_main.c |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

--- a/drivers/net/ethernet/intel/ice/ice_main.c
+++ b/drivers/net/ethernet/intel/ice/ice_main.c
@@ -5948,8 +5948,9 @@ ice_update_vsi_tx_ring_stats(struct ice_
 		u64 pkts = 0, bytes = 0;
 
 		ring = READ_ONCE(rings[i]);
-		if (ring)
-			ice_fetch_u64_stats_per_ring(&ring->syncp, ring->stats, &pkts, &bytes);
+		if (!ring)
+			continue;
+		ice_fetch_u64_stats_per_ring(&ring->syncp, ring->stats, &pkts, &bytes);
 		vsi_stats->tx_packets += pkts;
 		vsi_stats->tx_bytes += bytes;
 		vsi->tx_restart += ring->tx_stats.restart_q;