Hi Kurt,
see below.
> -----Original Message-----
> From: Kurt Van Dijck <dev.kurt@xxxxxxxxxxxxxxxxxxxxxx>
> Sent: Friday, June 12, 2020 9:43 AM
> Subject: Re: [PATCH] can: c_can: Handle lost bus-off interrupt while IRQs are
> disabled
>
> Hi Felix,
>
> Next question comes up.
> See inline.
>
> On vr, 12 jun 2020 09:10:44 +0200, Kurt Van Dijck wrote:
> > Thanks for verifying,
> >
> > I'll take a look how that can happen.
> >
> > I think packet loss is better (less packets lost) than before.
> >
> > Kurt
> >
> > On wo, 10 jun 2020 08:08:28 +0000, Felix Riemann wrote:
> > > Hi Kurt,
> > >
> > > > -----Original Message-----
> > > >
> > > > 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)
>
> It would be interesting to know idx and priv->tx_active here.
That's the statistic over about 1600 lines I captured. First number is number of occurrences:
992 can0: Skip @ idx 0, tx_active: 0x1
255 can0: Skip @ idx 0, tx_active: 0x3
250 can0: Skip @ idx 1, tx_active: 0x2
11 can0: Skip @ idx 0, tx_active: 0x7
10 can0: Skip @ idx 1, tx_active: 0x6
8 can0: Skip @ idx 7, tx_active: 0x80
8 can0: Skip @ idx 6, tx_active: 0xc0
8 can0: Skip @ idx 2, tx_active: 0x6
6 can0: Skip @ idx 1, tx_active: 0xe
5 can0: Skip @ idx 2, tx_active: 0x4
5 can0: Skip @ idx 0, tx_active: 0xf
4 can0: Skip @ idx 2, tx_active: 0xc
4 can0: Skip @ idx 0, tx_active: 0x3f
3 can0: Skip @ idx 6, tx_active: 0x40
3 can0: Skip @ idx 3, tx_active: 0xc
3 can0: Skip @ idx 2, tx_active: 0xfc
3 can0: Skip @ idx 2, tx_active: 0x3c
3 can0: Skip @ idx 0, tx_active: 0x1f
2 can0: Skip @ idx 5, tx_active: 0x3e
2 can0: Skip @ idx 4, tx_active: 0x3e
2 can0: Skip @ idx 3, tx_active: 0xf8
2 can0: Skip @ idx 3, tx_active: 0x3e
2 can0: Skip @ idx 2, tx_active: 0x3e
2 can0: Skip @ idx 1, tx_active: 0x3e
2 can0: Skip @ idx 1, tx_active: 0x1e
1 can0: Skip @ idx 7, tx_active: 0xf0
1 can0: Skip @ idx 6, tx_active: 0xf0
1 can0: Skip @ idx 6, tx_active: 0x78
1 can0: Skip @ idx 6, tx_active: 0x70
1 can0: Skip @ idx 5, tx_active: 0xf0
1 can0: Skip @ idx 5, tx_active: 0x78
1 can0: Skip @ idx 5, tx_active: 0x70
1 can0: Skip @ idx 5, tx_active: 0x38
1 can0: Skip @ idx 5, tx_active: 0x20
1 can0: Skip @ idx 4, tx_active: 0xf0
1 can0: Skip @ idx 4, tx_active: 0x38
1 can0: Skip @ idx 4, tx_active: 0x1c
1 can0: Skip @ idx 3, tx_active: 0xfc
1 can0: Skip @ idx 3, tx_active: 0xe
1 can0: Skip @ idx 3, tx_active: 0x8
1 can0: Skip @ idx 3, tx_active: 0x78
1 can0: Skip @ idx 3, tx_active: 0x38
1 can0: Skip @ idx 3, tx_active: 0x1c
1 can0: Skip @ idx 2, tx_active: 0xe
1 can0: Skip @ idx 2, tx_active: 0x7c
1 can0: Skip @ idx 2, tx_active: 0x1c
1 can0: Skip @ idx 1, tx_active: 0xfe
1 can0: Skip @ idx 0, tx_active: 0xff
1 can0: Skip @ idx 0, tx_active: 0x7f
I used atomic_read to get the value of tx_active.
Regards,
Felix
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