From: Marcelo Ricardo Leitner <marcelo.leitner@gmail•com>
To: Dmitry Vyukov <dvyukov@google•com>
Cc: David Ahern <dsahern@gmail•com>,
syzbot
<bot+21b498fc12cf2041655f8e1eeae0733807d794b3@syzkaller•appspotmail.com>,
LKML <linux-kernel@vger•kernel.org>,
Ingo Molnar <mingo@redhat•com>,
Peter Zijlstra <peterz@infradead•org>,
syzkaller-bugs@googlegroups•com,
David Miller <davem@davemloft•net>,
Florian Westphal <fw@strlen•de>,
Daniel Borkmann <daniel@iogearbox•net>,
Xin Long <lucien.xin@gmail•com>,
jakub.kicinski@netronome•com, mschiffer@universe-factory•net,
Vladislav Yasevich <vyasevich@gmail•com>,
Jiri Benc <jbenc@redhat•com>, netdev <netdev@vger•kernel.org>,
Neil Horman <nhorman@tuxdriver•com>,
linux-sctp@vger•kernel.org
Subject: Re: INFO: task hung in bpf_exit_net
Date: Fri, 22 Dec 2017 16:28:07 -0200 [thread overview]
Message-ID: <20171222182807.GC32765@localhost.localdomain> (raw)
In-Reply-To: <CACT4Y+aaSX4S3KHJjqkiQhhOZAtEN_fMD1m_Ve3rz4u4x9KSWg@mail.gmail.com>
On Fri, Dec 22, 2017 at 11:58:08AM +0100, Dmitry Vyukov wrote:
...
> > Same with this one, perhaps related to / fixed by:
> > http://patchwork.ozlabs.org/patch/850957/
> >
>
>
>
> Looking at the log, this one seems to be an infinite loop in SCTP code
> with console output in it. Kernel is busy printing gazilion of:
>
> [ 176.491099] sctp: sctp_transport_update_pmtu: Reported pmtu 508 too
> low, using default minimum of 512
> ** 110 printk messages dropped **
> [ 176.503409] sctp: sctp_transport_update_pmtu: Reported pmtu 508 too
> low, using default minimum of 512
> ** 103 printk messages dropped **
> ...
> [ 246.742374] sctp: sctp_transport_update_pmtu: Reported pmtu 508 too
> low, using default minimum of 512
> [ 246.742484] sctp: sctp_transport_update_pmtu: Reported pmtu 508 too
> low, using default minimum of 512
> [ 246.742590] sctp: sctp_transport_update_pmtu: Reported pmtu 508 too
> low, using default minimum of 512
>
> Looks like a different issue.
>
Oh. I guess this is caused by the interface having a MTU smaller than
SCTP_DEFAULT_MINSEGMENT (512), as the icmp frag needed handler
(sctp_icmp_frag_needed) will trigger an instant retransmission.
But as the MTU is smaller, SCTP won't update it, but will issue the
retransmission anyway.
I will test this soon. Should be fairly easy to trigger it.
Marcelo
next prev parent reply other threads:[~2017-12-22 18:28 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <001a1143fd00a8cc790560b0b552@google.com>
2017-12-19 12:47 ` INFO: task hung in bpf_exit_net Dmitry Vyukov
2017-12-19 16:21 ` Xin Long
2017-12-19 18:20 ` David Ahern
2017-12-22 10:58 ` Dmitry Vyukov
2017-12-22 11:16 ` Marcelo Ricardo Leitner
2017-12-22 11:24 ` Dmitry Vyukov
2017-12-22 18:28 ` Marcelo Ricardo Leitner [this message]
2017-12-22 19:04 ` Marcelo Ricardo Leitner
2018-02-02 23:39 ` Eric Biggers
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=20171222182807.GC32765@localhost.localdomain \
--to=marcelo.leitner@gmail$(echo .)com \
--cc=bot+21b498fc12cf2041655f8e1eeae0733807d794b3@syzkaller$(echo .)appspotmail.com \
--cc=daniel@iogearbox$(echo .)net \
--cc=davem@davemloft$(echo .)net \
--cc=dsahern@gmail$(echo .)com \
--cc=dvyukov@google$(echo .)com \
--cc=fw@strlen$(echo .)de \
--cc=jakub.kicinski@netronome$(echo .)com \
--cc=jbenc@redhat$(echo .)com \
--cc=linux-kernel@vger$(echo .)kernel.org \
--cc=linux-sctp@vger$(echo .)kernel.org \
--cc=lucien.xin@gmail$(echo .)com \
--cc=mingo@redhat$(echo .)com \
--cc=mschiffer@universe-factory$(echo .)net \
--cc=netdev@vger$(echo .)kernel.org \
--cc=nhorman@tuxdriver$(echo .)com \
--cc=peterz@infradead$(echo .)org \
--cc=syzkaller-bugs@googlegroups$(echo .)com \
--cc=vyasevich@gmail$(echo .)com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
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