net: ethernet: ti: cpsw: fix NULL pointer dereference in switch mode

In switch mode on struct cpsw_slave->ndev field will be initialized with proper value only for the one cpsw slave port, as result cpsw_get_usage_count() will generate "Unable to handle kernel NULL pointer dereference" exception when first ethernet interface is opening cpsw_ndo_open(). This issue causes boot regression on AM335x EVM and reproducible on am57xx-evm (switch mode). Fix it by adding additional check for !cpsw->slaves[i].ndev in cpsw_get_usage_count(). Cc: Ivan Khoronzhuk <[email protected]> Fixes: 03fd01a ("net: ethernet: ti: cpsw: don't duplicate ndev_running") Signed-off-by: Grygorii Strashko <[email protected]> Reviewed-by: Ivan Khoronzhuk <[email protected]> Signed-off-by: David S. Miller <[email protected]>
cail · Feb 1, 2017 · f696186 · f696186
1 parent b2504a5
commit f696186
Showing 1 changed file with 1 addition and 1 deletion.
diff --git a/drivers/net/ethernet/ti/cpsw.c b/drivers/net/ethernet/ti/cpsw.c
@@ -677,7 +677,7 @@ static int cpsw_get_usage_count(struct cpsw_common *cpsw)
 	u32 usage_count = 0;
 
 	for (i = 0; i < cpsw->data.slaves; i++)
-		if (netif_running(cpsw->slaves[i].ndev))
+		if (cpsw->slaves[i].ndev && netif_running(cpsw->slaves[i].ndev))
 			usage_count++;
 
 	return usage_count;