From: a.pichlkostner@gmx.de (Arthur Pichlkostner)
To: kernelnewbies@lists.kernelnewbies.org
Subject: How to find a bug with lost network messages
Date: Tue, 2 Feb 2016 20:05:58 +0100 [thread overview]
Message-ID: <20160202190558.GA1881@debi5.lan> (raw)
In-Reply-To: <56B07240.8070409@elfin.de>
I just know that netif_rx() should be updated to netif_rx_ni() for newer kernels.
Without the change I had NOHZ errors in the log, the same change was done in SLCAN.
Maybe this is the origin of your problem.
You can try our fork on https://github.com/tjohann/sllin which includes many improvents and fixes compared to the original driver from 2013.
On Tue, Feb 02, 2016 at 10:09:20AM +0100, Sandro Stiller wrote:
> Hello,
>
> I'm struggeling with a network driver (sllin[1]) which is not in the
> official kernel.
> It has a lot in common with the slcan driver but is used for LIN networks.
> The problem is, that sometimes messages sent to the network layer via
> netif_rx() don't arrive in all listening programs.
>
> This is how the driver works:
> 1. The application sends CAN messages to the network interface
> 2. The driver forwards it to the UART (tty)
> 3. The UART receives the same message (single-wire connection, RX and TX
> connected) and sends it back to the network layer
> 4. The sending application receives the previously sent message and can
> check for transmission errors and appended LIN slave replies.
>
> Sometimes the last point (4.) does not work after 10 - 40 seconds of
> transmission.
> The application does not receive the message using a blocking read() on
> the socket, but other processes receive it (running candump on the
> interface). netif_rx() always returns 0.
>
> If more programs are listening (running multiple instances of candump),
> the problem appears less often or never.
> On my PC there is no problem, it occures on ARM only.
> I'm using kernel 4.1.
>
> Can you give me a hint where to search for the cause of this behaviour?
>
> Thank you very much.
>
> Sandro
>
>
> [1]: https://github.com/sstiller/sllin/tree/master/sllin
>
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies at kernelnewbies.org
> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
prev parent reply other threads:[~2016-02-02 19:05 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-02-02 9:09 How to find a bug with lost network messages Sandro Stiller
2016-02-02 19:05 ` Arthur Pichlkostner [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20160202190558.GA1881@debi5.lan \
--to=a.pichlkostner@gmx.de \
--cc=kernelnewbies@lists.kernelnewbies.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).