Bug 1446914 - L2TP: "recursion detected" messages in dmesg output
Summary: L2TP: "recursion detected" messages in dmesg output
Keywords:
Status: CLOSED EOL
Alias: None
Product: Fedora
Classification: Fedora
Component: xl2tpd
Version: 25
Hardware: Unspecified
OS: Unspecified
unspecified
unspecified
Target Milestone: ---
Assignee: Paul Wouters
QA Contact: Fedora Extras Quality Assurance
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2017-04-30 12:30 UTC by Vlad Ivanov
Modified: 2019-06-25 08:35 UTC (History)
4 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed: 2017-12-12 10:08:11 UTC
Type: Bug
Embargoed:


Attachments (Terms of Use)


Links
System ID Private Priority Status Summary Last Updated
Debian BTS 856655 0 None None None 2017-04-30 12:30:53 UTC

Description Vlad Ivanov 2017-04-30 12:30:54 UTC
Description of problem:
L2TP VPN connection doesn't work. I can't access any hosts of the remote network. Connecting to the same server from Windows 7/8/10 works fine. dmesg output has a lot of messages like this:

[ +30,033294] net_ratelimit: 3 callbacks suppressed
[  +0,000005] ppp0: recursion detected
[  +0,000045] ppp0: recursion detected
[  +0,000048] ppp0: recursion detected
[  +0,000057] ppp0: recursion detected
[  +0,000072] ppp0: recursion detected
[  +0,000084] ppp0: recursion detected
[  +0,000096] ppp0: recursion detected
[  +0,000184] ppp0: recursion detected
[  +0,000165] ppp0: recursion detected
[  +0,000184] ppp0: recursion detected

Version-Release number of selected component (if applicable):
Fedora 25
Linux 4.10.12-200.fc25.x86_64
xl2tpd-1.3.9

Steps to Reproduce:
1. Create a VPN connection to a TP-Link router providing L2TP VPN service
2. Establish connection
3. Wait for dmesg messages to appear

Additional info:
This issue was causing soft lockups before. It was fixed with the following commit: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=55454a565836e1cb002d433e901804dea4406a32

Related bug:
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=856655

Logs:
dmesg:
[  +0,006035] IPv4 over IPsec tunneling driver
[  +2,283015] alg: No test for echainiv(authenc(hmac(sha1),cbc(des3_ede))) (echainiv(authenc(hmac(sha1-generic),cbc(des3_ede-generic))))
[  +0,052194] PPP generic driver version 2.4.2
[  +0,004187] NET: Registered protocol family 24
[  +0,007978] l2tp_core: L2TP core driver, V2.0
[  +0,002099] l2tp_netlink: L2TP netlink interface
[  +0,002637] l2tp_ppp: PPPoL2TP kernel driver, V2.0

systemd journal:
https://paste.fedoraproject.org/paste/zJ87OrtKCB4pZzczDGGclV5M1UNdIGYhyRLivL9gydE=

Comment 1 Fedora End Of Life 2017-11-16 19:34:32 UTC
This message is a reminder that Fedora 25 is nearing its end of life.
Approximately 4 (four) weeks from now Fedora will stop maintaining
and issuing updates for Fedora 25. It is Fedora's policy to close all
bug reports from releases that are no longer maintained. At that time
this bug will be closed as EOL if it remains open with a Fedora  'version'
of '25'.

Package Maintainer: If you wish for this bug to remain open because you
plan to fix it in a currently maintained version, simply change the 'version'
to a later Fedora version.

Thank you for reporting this issue and we are sorry that we were not
able to fix it before Fedora 25 is end of life. If you would still like
to see this bug fixed and are able to reproduce it against a later version
of Fedora, you are encouraged  change the 'version' to a later Fedora
version prior this bug is closed as described in the policy above.

Although we aim to fix as many bugs as possible during every release's
lifetime, sometimes those efforts are overtaken by events. Often a
more recent Fedora release includes newer upstream software that fixes
bugs or makes them obsolete.

Comment 2 Fedora End Of Life 2017-12-12 10:08:11 UTC
Fedora 25 changed to end-of-life (EOL) status on 2017-12-12. Fedora 25 is
no longer maintained, which means that it will not receive any further
security or bug fix updates. As a result we are closing this bug.

If you can reproduce this bug against a currently maintained version of
Fedora please feel free to reopen this bug against that version. If you
are unable to reopen this bug, please file a new report against the
current release. If you experience problems, please add a comment to this
bug.

Thank you for reporting this bug and we are sorry it could not be fixed.

Comment 3 Paul Wouters 2017-12-13 17:17:28 UTC
Can you still reproduce this? If so what kernel version? Some people reported issues with 4.14 and some 4.13 kernels with backports and that it broke l2tp/ipsec

Comment 4 Douglas Kosovic 2017-12-15 12:03:29 UTC
Have someone using NetworkManager-l2tp 1.2.8 who reported an issue with kernel 4.14.3 and 4.14.5, but not with some 4.13 kernels, see:
    https://bugzilla.redhat.com/show_bug.cgi?id=1526203

Upstream libreswan report :
    https://github.com/libreswan/libreswan/issues/140

Comment 5 Paul Wouters 2017-12-15 15:04:41 UTC
also 4.15.0 seems to work fine?

Comment 6 Douglas Kosovic 2017-12-15 23:44:18 UTC
On Fedora 27 can confirm I'm able to establish a L2TP/IPsec connection with kernel-4.15.0-0.rc3.git0.1.fc28.

Unfortunately kernel-4.14.6-300.fc27 in testing still has the issue.

Comment 7 udo 2019-06-25 08:35:30 UTC
I see this on Fedora 30 with pppoE in use in pppd.


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