netdev - Re: [Patch net-next] net: dump more useful information in netdev_rx_csum

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Message-ID: <CAM_iQpXeudFkHrJdCe3FCyNTxBO_YyvSb1rvSsbHBg1Yuy9m8g@mail.gmail.com>
Date:   Fri, 9 Nov 2018 17:42:09 -0800
From:   Cong Wang <xiyou.wangcong@...il.com>
To:     linyunsheng@...wei.com
Cc:     Linux Kernel Network Developers <netdev@...r.kernel.org>
Subject: Re: [Patch net-next] net: dump more useful information in netdev_rx_csum_fault()

On Fri, Nov 9, 2018 at 5:39 PM Yunsheng Lin <linyunsheng@...wei.com> wrote:
>
> On 2018/11/10 3:43, Cong Wang wrote:
> > Currently netdev_rx_csum_fault() only shows a device name,
> > we need more information about the skb for debugging.
> >
> > Sample output:
> >
> >  ens3: hw csum failure
> >  dev features: 0x0000000000014b89
> >  skb len=84 data_len=0 gso_size=0 gso_type=0 ip_summed=0 csum=0, csum_complete_sw=0, csum_valid=0
> >
> > Signed-off-by: Cong Wang <xiyou.wangcong@...il.com>
> > ---
> >  include/linux/netdevice.h |  5 +++--
> >  net/core/datagram.c       |  6 +++---
> >  net/core/dev.c            | 10 ++++++++--
> >  net/sunrpc/socklib.c      |  2 +-
> >  4 files changed, 15 insertions(+), 8 deletions(-)
> >
> > diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
> > index 857f8abf7b91..fabcd9fa6cf7 100644
> > --- a/include/linux/netdevice.h
> > +++ b/include/linux/netdevice.h
> > @@ -4332,9 +4332,10 @@ static inline bool can_checksum_protocol(netdev_features_t features,
> >  }
> >
> >  #ifdef CONFIG_BUG
> > -void netdev_rx_csum_fault(struct net_device *dev);
> > +void netdev_rx_csum_fault(struct net_device *dev, struct sk_buff *skb);
> >  #else
> > -static inline void netdev_rx_csum_fault(struct net_device *dev)
> > +static inline void netdev_rx_csum_fault(struct net_device *dev,
> > +                                     struct sk_buff *skb)
> >  {
> >  }
> >  #endif
> > diff --git a/net/core/datagram.c b/net/core/datagram.c
> > index 57f3a6fcfc1e..d8f4d55cd6c5 100644
> > --- a/net/core/datagram.c
> > +++ b/net/core/datagram.c
> > @@ -736,7 +736,7 @@ __sum16 __skb_checksum_complete_head(struct sk_buff *skb, int len)
> >       if (likely(!sum)) {
> >               if (unlikely(skb->ip_summed == CHECKSUM_COMPLETE) &&
> >                   !skb->csum_complete_sw)
> > -                     netdev_rx_csum_fault(skb->dev);
> > +                     netdev_rx_csum_fault(skb->dev, skb);
> >       }
> >       if (!skb_shared(skb))
> >               skb->csum_valid = !sum;
> > @@ -756,7 +756,7 @@ __sum16 __skb_checksum_complete(struct sk_buff *skb)
> >       if (likely(!sum)) {
> >               if (unlikely(skb->ip_summed == CHECKSUM_COMPLETE) &&
> >                   !skb->csum_complete_sw)
> > -                     netdev_rx_csum_fault(skb->dev);
> > +                     netdev_rx_csum_fault(skb->dev, skb);
> >       }
> >
> >       if (!skb_shared(skb)) {
> > @@ -810,7 +810,7 @@ int skb_copy_and_csum_datagram_msg(struct sk_buff *skb,
> >
> >               if (unlikely(skb->ip_summed == CHECKSUM_COMPLETE) &&
> >                   !skb->csum_complete_sw)
> > -                     netdev_rx_csum_fault(NULL);
> > +                     netdev_rx_csum_fault(NULL, skb);
> >       }
> >       return 0;
> >  fault:
> > diff --git a/net/core/dev.c b/net/core/dev.c
> > index 0ffcbdd55fa9..2b337df26117 100644
> > --- a/net/core/dev.c
> > +++ b/net/core/dev.c
> > @@ -3091,10 +3091,16 @@ EXPORT_SYMBOL(__skb_gso_segment);
> >
> >  /* Take action when hardware reception checksum errors are detected. */
> >  #ifdef CONFIG_BUG
> > -void netdev_rx_csum_fault(struct net_device *dev)
> > +void netdev_rx_csum_fault(struct net_device *dev, struct sk_buff *skb)
> >  {
> >       if (net_ratelimit()) {
> >               pr_err("%s: hw csum failure\n", dev ? dev->name : "<unknown>");
> > +             if (dev)
> > +                     pr_err("dev features: %pNF\n", &dev->features);
> > +             pr_err("skb len=%d data_len=%d gso_size=%d gso_type=%d ip_summed=%d csum=%x, csum_complete_sw=%d, csum_valid=%d\n",
> > +                    skb->len, skb->data_len, skb_shinfo(skb)->gso_size,
> > +                    skb_shinfo(skb)->gso_type, skb->ip_summed, skb->csum,
> > +                    skb->csum_complete_sw, skb->csum_valid);
>
>
> This function also have the netdev available, use netdev_err to log the error?

It is apparently not me who picked pr_err() from the beginning,
I just follow that pr_err(). If you are not happy with it, please send
a followup.


>
> Also, dev->features was dumped before this patch, why remove it?

Seriously? Where do I remove it? Please be specific. :)