From ee5929c1e85ebdc94f938481e90f7e8723083563 Mon Sep 17 00:00:00 2001 From: Nathan Chancellor Date: Sun, 19 Mar 2023 16:41:08 -0700 Subject: [PATCH] net: pasemi: Fix return type of pasemi_mac_start_tx() [ Upstream commit c8384d4a51e7cb0e6587f3143f29099f202c5de1 ] With clang's kernel control flow integrity (kCFI, CONFIG_CFI_CLANG), indirect call targets are validated against the expected function pointer prototype to make sure the call target is valid to help mitigate ROP attacks. If they are not identical, there is a failure at run time, which manifests as either a kernel panic or thread getting killed. A warning in clang aims to catch these at compile time, which reveals: drivers/net/ethernet/pasemi/pasemi_mac.c:1665:21: error: incompatible function pointer types initializing 'netdev_tx_t (*)(struct sk_buff *, struct net_device *)' (aka 'enum netdev_tx (*)(struct sk_buff *, struct net_device *)') with an expression of type 'int (struct sk_buff *, struct net_device *)' [-Werror,-Wincompatible-function-pointer-types-strict] .ndo_start_xmit = pasemi_mac_start_tx, ^~~~~~~~~~~~~~~~~~~ 1 error generated. ->ndo_start_xmit() in 'struct net_device_ops' expects a return type of 'netdev_tx_t', not 'int'. Adjust the return type of pasemi_mac_start_tx() to match the prototype's to resolve the warning. While PowerPC does not currently implement support for kCFI, it could in the future, which means this warning becomes a fatal CFI failure at run time. Link: https://github.com/ClangBuiltLinux/linux/issues/1750 Signed-off-by: Nathan Chancellor Reviewed-by: Horatiu Vultur Link: https://lore.kernel.org/r/20230319-pasemi-incompatible-pointer-types-strict-v1-1-1b9459d8aef0@kernel.org Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin --- drivers/net/ethernet/pasemi/pasemi_mac.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/net/ethernet/pasemi/pasemi_mac.c b/drivers/net/ethernet/pasemi/pasemi_mac.c index aaab590..ed7dd0a 100644 --- a/drivers/net/ethernet/pasemi/pasemi_mac.c +++ b/drivers/net/ethernet/pasemi/pasemi_mac.c @@ -1423,7 +1423,7 @@ static void pasemi_mac_queue_csdesc(const struct sk_buff *skb, write_dma_reg(PAS_DMA_TXCHAN_INCR(txring->chan.chno), 2); } -static int pasemi_mac_start_tx(struct sk_buff *skb, struct net_device *dev) +static netdev_tx_t pasemi_mac_start_tx(struct sk_buff *skb, struct net_device *dev) { struct pasemi_mac * const mac = netdev_priv(dev); struct pasemi_mac_txring * const txring = tx_ring(mac); -- 2.7.4