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

Warning was found when cross compiling using aarch64-linux-gnu-gcc (GCC)
15.1.0.

Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@intel.com>
Link: https://patch.msgid.link/20250913133229.2087822-1-niklas.soderlund+renesas@ragnatech.se
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/ethernet/renesas/ravb_main.c b/drivers/net/ethernet/renesas/ravb_main.c
index 94b6fb94f8f17de31cdfb3e9f875c8980e6042f1..9d3bd65b85ffbc2c4ce5f06a61bd8ccaf20717d3 100644 (file)
--- 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)