Re: [2/2,v3] myri10ge: avoid uninitialized variable use

[Jakub Kicinski <kuba@kernel.org>]

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---
myri10ge: avoid uninitialized variable use

This patch fixes uninitialized variable warnings found by gcc-10 on s390
by initializing cmd.data0, cmd.data1, and cmd.data2 before calls to
myri10ge_send_cmd() across multiple functions.

> diff --git a/drivers/net/ethernet/myricom/myri10ge/myri10ge.c b/drivers/net/ethernet/myricom/myri10ge/myri10ge.c
> --- a/drivers/net/ethernet/myricom/myri10ge/myri10ge.c
> +++ b/drivers/net/ethernet/myricom/myri10ge/myri10ge.c

[ ... ]

> @@ -2238,6 +2250,8 @@ static int myri10ge_get_txrx(struct myri10ge_priv *mgp, int slice)
>  	status = 0;
>  	if (slice == 0 || (mgp->dev->real_num_tx_queues > 1)) {
>  		cmd.data0 = slice;
> +		cmd.data1 = 0;
> +		cmd.data2 = 0;
>  		status = myri10ge_send_cmd(mgp, MXGEFW_CMD_GET_SEND_OFFSET,
>  					   &cmd, 0);
>  		ss->tx.lanai = (struct mcp_kreq_ether_send __iomem *)
>  			    (mgp->sram + cmd.data0);
>  	}
>  	cmd.data0 = slice;
>  	status |= myri10ge_send_cmd(mgp, MXGEFW_CMD_GET_SMALL_RX_OFFSET,
>  				    &cmd, 0);

The initialization of cmd.data1 and cmd.data2 is inside the conditional
block. When slice > 0 and real_num_tx_queues <= 1, does the subsequent
myri10ge_send_cmd() call for MXGEFW_CMD_GET_SMALL_RX_OFFSET use
uninitialized data1/data2 values?

Simon Horman pointed this out in his review of v2:
https://lore.kernel.org/all/20250622162715.GA297140@horms.kernel.org/

He provided a diff showing that the second cmd.data0 = slice assignment
also needs cmd.data1 and cmd.data2 initialization. This feedback does
not appear to have been addressed in v3.
-- 
pw-bot: cr