Re: [PATCH net] can: ctucanfd: handle bus error interrupts

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:

Pre-existing issues:
- [High] Un-ratelimited `netdev_info()` on bus errors causes a printk flood.
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--- Patch [1]: [PATCH net] can: ctucanfd: handle bus error interrupts ---
commit dcd94808a20ebfaa5db627f0ee1ba372c3c77c87
Author: Avi Weiss <[email protected]>

can: ctucanfd: handle bus error interrupts

Include REG_INT_STAT_BEI in the top-level error interrupt condition.

BEI is enabled when CAN_CTRLMODE_BERR_REPORTING is requested and
ctucan_err_interrupt() already handles it. Without checking and
clearing BEI in the top-level handler, bus error interrupts are not
handled or acknowledged.

> diff --git a/drivers/net/can/ctucanfd/ctucanfd_base.c b/drivers/net/can/ctucanfd/ctucanfd_base.c
> index 0ea1ff28dfce8..0cd2d428c1f15 100644
> --- a/drivers/net/can/ctucanfd/ctucanfd_base.c
> +++ b/drivers/net/can/ctucanfd/ctucanfd_base.c
> @@ -1136,8 +1136,12 @@ static irqreturn_t ctucan_interrupt(int irq, void *dev_id)
>  		/* Error interrupts */
>  		if (FIELD_GET(REG_INT_STAT_EWLI, isr) ||
>  		    FIELD_GET(REG_INT_STAT_FCSI, isr) ||
> -		    FIELD_GET(REG_INT_STAT_ALI, isr)) {
> -			icr = isr & (REG_INT_STAT_EWLI | REG_INT_STAT_FCSI | REG_INT_STAT_ALI);
> +		    FIELD_GET(REG_INT_STAT_ALI, isr) ||
> +		    FIELD_GET(REG_INT_STAT_BEI, isr)) {
> +			icr = isr & (REG_INT_STAT_EWLI |
> +				     REG_INT_STAT_FCSI |
> +				     REG_INT_STAT_ALI |
> +				     REG_INT_STAT_BEI);
>  
>  			ctucan_netdev_dbg(ndev, "some ERR interrupt: clearing 0x%08x\n", icr);
>  			ctucan_write32(priv, CTUCANFD_INT_STAT, icr);

[Severity: High]
This isn't a bug introduced by this patch, but since we are now passing
REG_INT_STAT_BEI into ctucan_err_interrupt() which is called directly after
this write, could this cause a printk flood?

Looking at ctucan_err_interrupt():

	/* Check for Bus Error interrupt */
	if (FIELD_GET(REG_INT_STAT_BEI, isr)) {
		netdev_info(ndev, "bus error\n");

This unconditional netdev_info() is called for every bus error interrupt,
whereas other errors like ALI correctly use a dologerr ratelimit check.

Would a flurry of bus errors overwhelm the system log?

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Sashiko AI review · https://sashiko.dev/#/patchset/[email protected]?part=1