Bug 1468395

Summary: VPN Causes 100% CPU - Missing Route
Product: [Fedora] Fedora Reporter: James <james>
Component: NetworkManager-pptpAssignee: Lubomir Rintel <lkundrak>
Status: CLOSED EOL QA Contact: Fedora Extras Quality Assurance <extras-qa>
Severity: unspecified Docs Contact:
Priority: unspecified    
Version: 25CC: code, dcbw, lkundrak, thaller
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Last Closed: 2017-12-12 10:25:35 UTC Type: Bug
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description James 2017-07-07 00:03:41 UTC
Description of problem:
Create a VPN Connection and millions of packets go out the GRE tunnel


Version-Release number of selected component (if applicable):
NetworkManager-pptp-gnome-1.2.4-1.fc25.x86_64
NetworkManager-pptp-1.2.4-1.fc25.x86_64
pptp-1.9.0-1.fc25.x86_64

Linux localhost.localdomain 4.11.8-200.fc25.x86_64 #1 SMP Thu Jun 29 16:13:56 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux


How reproducible:

Add A VPN - Route only vpn traffic doesn't help either way.

Network Manager Config:

[connection]
id=VPN
uuid=2f8d94e8-fd57-44be-9f5b-74fe651a045b
type=vpn
autoconnect=false
permissions=[REMOVED]
secondaries=
timestamp=1499307382
zone=trusted

[vpn]
gateway=[REMOVED]
password-flags=1
refuse-chap=yes
refuse-eap=yes
refuse-mschap=yes
refuse-pap=yes
user=[REMOVED]
service-type=org.freedesktop.NetworkManager.pptp

[ipv4]
dns-search=
method=auto
never-default=true
route1=192.168.4.0/24,[VPNIP],10

[ipv6]
addr-gen-mode=stable-privacy
dns-search=
method=ignore




Actual results:
100% CPU no VPN
Computer Overheating
Can still ping local gateway

Expected results:
VPN

Additional info:

Routing Seems to be Wrong:


Route Before VPN:
[root@localhost sbin]# route -n
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
0.0.0.0         192.168.0.1     0.0.0.0         UG    600    0        0 wlp4s0
192.168.0.0     0.0.0.0         255.255.255.0   U     600    0        0 wlp4s0
192.168.122.0   0.0.0.0         255.255.255.0   U     0      0        0 virbr0

Route After VPN NOT WORKING:
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
0.0.0.0         192.168.0.1     0.0.0.0         UG    600    0        0 wlp4s0
192.168.0.0     0.0.0.0         255.255.255.0   U     600    0        0 wlp4s0
192.168.0.1     0.0.0.0         255.255.255.255 UH    600    0        0 wlp4s0
192.168.4.0     [VPNIPADDR]     255.255.255.0   UG    10     0        0 ppp0
192.168.122.0   0.0.0.0         255.255.255.0   U     0      0        0 virbr0
[VPNIPADDR]     0.0.0.0         255.255.255.255 UH    50     0        0 ppp0


After booting kernel 
Linux localhost.localdomain 4.8.6-300.fc25.x86_64 #1 SMP Tue Nov 1 12:36:38 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux

Connect to same VPN same settings- WORKS:
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
0.0.0.0         192.168.0.1     0.0.0.0         UG    600    0        0 wlp4s0
192.168.0.0     0.0.0.0         255.255.255.0   U     600    0        0 wlp4s0
192.168.0.1     0.0.0.0         255.255.255.255 UH    600    0        0 wlp4s0
192.168.4.0     [VPNIPADDR]     255.255.255.0   UG    10     0        0 ppp0
192.168.122.0   0.0.0.0         255.255.255.0   U     0      0        0 virbr0
[VPNIPADDR]     192.168.0.1     255.255.255.255 UGH   0      0        0 wlp4s0 << MISSING FROM ABOVE
[VPNIPADDR]     0.0.0.0         255.255.255.255 UH    50     0        0 ppp0

Comment 1 Thomas Haller 2017-07-10 10:43:08 UTC
which process consumes 100% CPU? Try `ps` or `top`.

Comment 2 James 2017-07-10 19:03:40 UTC
top - 12:01:32 up 1 min,  1 user,  load average: 2.78, 1.04, 0.38
Tasks: 214 total,   3 running, 211 sleeping,   0 stopped,   0 zombie
%Cpu(s): 17.6 us, 22.1 sy,  0.0 ni, 39.2 id,  0.0 wa,  0.0 hi, 21.0 si,  0.0 st
KiB Mem :  7912980 total,  5899996 free,  1374436 used,   638548 buff/cache
KiB Swap:  7815164 total,  7815164 free,        0 used.  6254020 avail Mem 

  PID USER      PR  NI    VIRT    RES    SHR S  %CPU %MEM     TIME+ COMMAND                                                            
 2138 root      20   0    6472    704    628 D  55.8  0.0   0:24.99 pptpgw                                                             
   18 root      20   0       0      0      0 S  29.9  0.0   0:09.71 ksoftirqd/1                                                        
  107 root      20   0       0      0      0 R  17.6  0.0   0:04.37 kworker/u4:5 



 2138 ?        R      0:39 /sbin/pptp 216.171.98.93 --nolaunchpppd --loglevel 0 --logstring nm-pptp-service-2105

Comment 3 Thomas Haller 2017-07-17 14:19:44 UTC
sounds like http://pptpclient.sourceforge.net/howto-diagnosis.phtml#ip_loop

From the redacted routing table it's not entirely clear to me, but it seems that you route [VPNIPADDR] via the VPN tunnel itself. That would be a mis-configuration.

  route1=192.168.4.0/24,[VPNIP],10

looks wrong. Does it work if you replace [VPNIP] with 0.0.0.0 ?

Comment 4 James 2017-07-22 04:15:55 UTC
If I boot the older kernel the same configuration works.

I've tried with and without that route on there the result is the same.


The problem is the one very important route is missing when I boot the latest kernel.

This one:

[VPNIPADDR]     192.168.0.1     255.255.255.255 UGH   0      0        0 wlp4s0 << MISSING FROM ABOVE


Maybe the new fedora will fix this.. don't have time to upgrade at the moment and I can live with an older kernel.

Comment 5 Fedora End Of Life 2017-11-16 19:39:28 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 6 Fedora End Of Life 2017-12-12 10:25:35 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 7 James 2017-12-12 18:26:22 UTC
Note the following stops the packet loop created by pptp


sudo route add -host VPNIP/32 gw ORIGINALGATEWAYIP dev wlp4s0