netdev - [net-next] net: ravb: Fix -Wmaybe-uninitialized warning

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Message-ID: <20250912130624.1022028-1-niklas.soderlund+renesas@ragnatech.se>
Date: Fri, 12 Sep 2025 15:06:24 +0200
From: Niklas Söderlund <niklas.soderlund+renesas@...natech.se>
To: Paul Barker <paul@...rker.dev>,
	Andrew Lunn <andrew+netdev@...n.ch>,
	"David S. Miller" <davem@...emloft.net>,
	Eric Dumazet <edumazet@...gle.com>,
	Jakub Kicinski <kuba@...nel.org>,
	Paolo Abeni <pabeni@...hat.com>,
	netdev@...r.kernel.org,
	linux-renesas-soc@...r.kernel.org
Cc: Niklas Söderlund <niklas.soderlund+renesas@...natech.se>
Subject: [net-next] net: ravb: Fix -Wmaybe-uninitialized warning

Fix a -Wmaybe-uninitialized warning by initializing the variable to
NULL. The warning is bogus and should not happen, but fixing it allows
running the check on the driver to catch potential future problems.

  $ make CFLAGS_ravb_main.o=-Wmaybe-uninitialized

  In function 'ravb_rx_csum_gbeth',
      inlined from 'ravb_rx_gbeth' at .../linux/drivers/net/ethernet/renesas/ravb_main.c:923:6:
  .../linux/drivers/net/ethernet/renesas/ravb_main.c:765:25: error: 'skb' may be used uninitialized [-Werror=maybe-uninitialized]
    765 |         if (unlikely(skb->len < csum_len))
        |                      ~~~^~~~~
  .../linux/include/linux/compiler.h:77:45: note: in definition of macro 'unlikely'
     77 | # define unlikely(x)    __builtin_expect(!!(x), 0)
        |                                             ^
  .../linux/drivers/net/ethernet/renesas/ravb_main.c: In function 'ravb_rx_gbeth':
  .../linux/drivers/net/ethernet/renesas/ravb_main.c:806:25: note: 'skb' was declared here
    806 |         struct sk_buff *skb;
        |                         ^~~
  cc1: all warnings being treated as errors

Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@...natech.se>
---
 drivers/net/ethernet/renesas/ravb_main.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/renesas/ravb_main.c b/drivers/net/ethernet/renesas/ravb_main.c
index 94b6fb94f8f1..9d3bd65b85ff 100644
--- a/drivers/net/ethernet/renesas/ravb_main.c
+++ b/drivers/net/ethernet/renesas/ravb_main.c
@@ -802,7 +802,6 @@ static int ravb_rx_gbeth(struct net_device *ndev, int budget, int q)
 	const struct ravb_hw_info *info = priv->info;
 	struct net_device_stats *stats;
 	struct ravb_rx_desc *desc;
-	struct sk_buff *skb;
 	int rx_packets = 0;
 	u8  desc_status;
 	u16 desc_len;
@@ -815,6 +814,8 @@ static int ravb_rx_gbeth(struct net_device *ndev, int budget, int q)
 	stats = &priv->stats[q];
 
 	for (i = 0; i < limit; i++, priv->cur_rx[q]++) {
+		struct sk_buff *skb = NULL;
+
 		entry = priv->cur_rx[q] % priv->num_rx_ring[q];
 		desc = &priv->rx_ring[q].desc[entry];
 		if (rx_packets == budget || desc->die_dt == DT_FEMPTY)
-- 
2.51.0