Hi Kurt,
> -----Original Message-----
> From: Kurt Van Dijck <dev.kurt@xxxxxxxxxxxxxxxxxxxxxx>
> Sent: Wednesday, April 29, 2020 11:06 AM
> Subject: Re: [PATCH] can: c_can: Handle lost bus-off interrupt while IRQs are
> disabled
>
> I have the impression that the recv path is covered, at least the null ptr would
> have caused issued earlier already.
> Would the problem arise in c_can_do_tx fetching a NULL echo_skb?
It really looks like it.
Adding a BUG_ON to the loop in c_can_do_tx triggers with a NULL skb returned by __can_get_echo_skb().
For testing I replaced the BUG_ON with a check that skips the skb if that happens (not sure if that would be a valid fix in that place):
while ((obj = c_can_ffs64(pend))) {
pend &= ~((u64)1 << (obj - 1));
c_can_inval_tx_object(dev, IF_RX, obj);
idx = obj - priv->obj.send_frst;
skb = __can_get_echo_skb(dev, idx, &len);
if(!skb)
continue;
can_rx_offload_irq_receive_skb(&priv->offload, skb);
bytes += len;
pkts++;
}
So far it got through the night without crashing or deadlocking, but I can't really tell if we are missing pakets though.
Regards,
Felix
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