net: macb: fix the restore of cmp registers

commit a714e27 upstream.

Commit a14d273 ("net: macb: restore cmp registers on resume path")
introduces the restore of CMP registers on resume path. In case the IP
doesn't support type 2 screeners (zero on DCFG8 register) the
struct macb::rx_fs_list::list is not initialized and thus the
list_for_each_entry(item, &bp->rx_fs_list.list, list) loop introduced in
commit a14d273 ("net: macb: restore cmp registers on resume path")
will access an uninitialized list leading to crash. Thus, initialize
the struct macb::rx_fs_list::list without taking into account if the
IP supports type 2 screeners or not.

Fixes: a14d273 ("net: macb: restore cmp registers on resume path")
Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/net/ethernet/cadence/macb_main.c

@@ -3914,6 +3914,7 @@ static int macb_init(struct platform_device *pdev)
 	reg = gem_readl(bp, DCFG8);
 	bp->max_tuples = min((GEM_BFEXT(SCR2CMP, reg) / 3),
 			GEM_BFEXT(T2SCR, reg));
+	INIT_LIST_HEAD(&bp->rx_fs_list.list);
 	if (bp->max_tuples > 0) {
 		/* also needs one ethtype match to check IPv4 */
 		if (GEM_BFEXT(SCR2ETH, reg) > 0) {
@@ -3924,7 +3925,6 @@ static int macb_init(struct platform_device *pdev)
 			/* Filtering is supported in hw but don't enable it in kernel now */
 			dev->hw_features |= NETIF_F_NTUPLE;
 			/* init Rx flow definitions */
-			INIT_LIST_HEAD(&bp->rx_fs_list.list);
 			bp->rx_fs_list.count = 0;
 			spin_lock_init(&bp->rx_fs_lock);
 		} else