Re: [PATCH v1] mailbox: mchp-ipc-sbi: fix uninitialized symbol and other smatch warnings

[Dan Carpenter]

On Thu, Dec 18, 2025 at 10:33:59AM +0000, Valentina Fernandez wrote:
> Fix uninitialized symbol 'hartid' warning in mchp_ipc_cluster_aggr_isr()
> by introducing a 'found' flag to track whether the IRQ matches any
> online hart. If no match is found, return IRQ_NONE.
> 
> Also fix other smatch warnings by removing dead code in
> mchp_ipc_startup() and by returning -ENODEV in dev_err_probe() if the
> Microchip SBI extension is not found.
> 
> Fixes below smatch warnings:
> drivers/mailbox/mailbox-mchp-ipc-sbi.c:187 mchp_ipc_cluster_aggr_isr() error: uninitialized symbol 'hartid'.
> drivers/mailbox/mailbox-mchp-ipc-sbi.c:324 mchp_ipc_startup() warn: ignoring unreachable code.
> drivers/mailbox/mailbox-mchp-ipc-sbi.c:422 mchp_ipc_probe() warn: passing zero to 'dev_err_probe'
> 
> Reported-by: kernel test robot <lkp@xxxxxxxxx>
> Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
> Closes: https://lore.kernel.org/r/202512171533.CDLdScMY-lkp@xxxxxxxxx/
> Signed-off-by: Valentina Fernandez <valentina.fernandezalanis@xxxxxxxxxxxxx>
> ---
>  drivers/mailbox/mailbox-mchp-ipc-sbi.c | 21 +++++++++------------
>  1 file changed, 9 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/mailbox/mailbox-mchp-ipc-sbi.c b/drivers/mailbox/mailbox-mchp-ipc-sbi.c
> index d444491a584e..b87bf2fb4b9b 100644
> --- a/drivers/mailbox/mailbox-mchp-ipc-sbi.c
> +++ b/drivers/mailbox/mailbox-mchp-ipc-sbi.c
> @@ -174,17 +174,21 @@ static irqreturn_t mchp_ipc_cluster_aggr_isr(int irq, void *data)
>  	struct mchp_ipc_msg ipc_msg;
>  	struct mchp_ipc_status status_msg;
>  	int ret;
> -	unsigned long hartid;
>  	u32 i, chan_index, chan_id;
> +	bool found = false;
>  
>  	/* Find out the hart that originated the irq */
>  	for_each_online_cpu(i) {
> -		hartid = cpuid_to_hartid_map(i);
> -		if (irq == ipc->cluster_cfg[i].irq)
> +		if (irq == ipc->cluster_cfg[i].irq) {
> +			found = true;
>  			break;
> +		}
>  	}
>  
> -	status_msg.cluster = hartid;
> +	if (unlikely(!found))
> +		return IRQ_NONE;

This one is a false positive because obviously there is going to be
at least one online cpu.  I would prefer to silence this in Smatch.
Generally, you should ignore static checker false positives.

regards,
dan carpenter