Ubuntu
qemu-kvm package

kvm hangs at 100% cpu when connecting to forwarded ports (when listed incorrectly on the command line)

Bug #453617 reported by Jesse Michael
6
This bug affects 1 person
Affects Status Importance Assigned to Milestone
QEMU
Fix Released
Undecided
Unassigned
qemu-kvm (Ubuntu)
Fix Released
Low
Dustin Kirkland 
Lucid
Fix Released
Low
Dustin Kirkland 

Bug Description

Binary package hint: qemu-kvm

If kvm is started using two separate "-net user,hostfwd=<forwarding rule>" arguments to forward ports from the host to the client, it won't complain, but will return a connection refused error and hang at 100% cpu when trying to connect to either forwarded port.

However, if kvm is started with the hostfwd rules combined together into a single "-net user" argument, it works fine.

As an example, this command line doesn't generate any warnings or errors, but causes kvm to hang for me:

kvm -net nic -net user,hostfwd=tcp:127.0.0.1:8888-:80 -net user,hostfwd=tcp:127.0.0.1:2222-:22 -m 128 -smp 1 -drive file=disk0.qcow2

... but this command line works fine:

kvm -net nic -net user,hostfwd=tcp:127.0.0.1:8888-:80,hostfwd=tcp:127.0.0.1:2222-:22 -m 128 -smp 1 -drive file=disk0.qcow2

ProblemType: Bug
Architecture: amd64
Date: Fri Oct 16 17:19:59 2009
DistroRelease: Ubuntu 9.10
KvmCmdLine: Error: command ['ps', '-C', 'kvm', '-F'] failed with exit code 1: UID PID PPID C SZ RSS PSR STIME TTY TIME CMD
MachineType: Sony Corporation VGN-SZ650N
NonfreeKernelModules: nvidia
Package: kvm (not installed)
PccardctlIdent:
 Socket 0:
   no product info available
PccardctlStatus:
 Socket 0:
   no card
ProcCmdLine: root=UUID=3ee4953e-48f0-497c-ae78-18cbb18cfef8 ro quiet splash
ProcEnviron:
 LANGUAGE=en_US.UTF-8
 PATH=(custom, user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
ProcVersionSignature: Ubuntu 2.6.31-14.47-generic
SourcePackage: qemu-kvm
Uname: Linux 2.6.31-14-generic x86_64
dmi.bios.date: 07/12/2007
dmi.bios.vendor: Phoenix Technologies LTD
dmi.bios.version: R0081S5
dmi.board.asset.tag: N/A
dmi.board.name: VAIO
dmi.board.vendor: Sony Corporation
dmi.board.version: N/A
dmi.chassis.type: 10
dmi.chassis.vendor: Sony Corporation
dmi.chassis.version: N/A
dmi.modalias: dmi:bvnPhoenixTechnologiesLTD:bvrR0081S5:bd07/12/2007:svnSonyCorporation:pnVGN-SZ650N:pvrJ002VXGP:rvnSonyCorporation:rnVAIO:rvrN/A:cvnSonyCorporation:ct10:cvrN/A:
dmi.product.name: VGN-SZ650N
dmi.product.version: J002VXGP
dmi.sys.vendor: Sony Corporation

Related branches

lp:ubuntu/maverick/qemu-kvm
Revision history for this message
Jesse Michael (jesse.michael) wrote :
Soren Hansen (soren)
Changed in qemu-kvm (Ubuntu):
status: New → Confirmed
importance: Undecided → Low
Revision history for this message
Torsten Spindler (tspindler) wrote :

On Lucid alpha 3 an error is reported and kvm stops:

$ sudo kvm -net nic -net user,hostfwd=tcp:127.0.0.1:8888-:80 -net user,hostfwd=tcp:127.0.0.1:2222-:22 -m 128 -smp 1 -drive file=disk0.qcow2kvm -net nic -net user,hostfwd=tcp:127.0.0.1:8888-:80 -net user,hostfwd=tcp:127.0.0.1:2222-:22 -m 128 -smp 1 -drive file=lucid.qcow2
could not set up host forwarding rule 'tcp:127.0.0.1:8888-:80'

qemu-kvm Version: 0.12.3-0ubuntu2

Revision history for this message
Dustin Kirkland  (kirkland) wrote :

Torsten-

Check your command line. Looks like you double-pasted the faulty command.

Jesse-

I can actually confirm this in Lucid's qemu-kvm 0.12.3. I ran your exact two lines and it seems to lock my kvm process and eat a bunch of cpu.

The symptoms look very similar to Bug #474968.

Anthony, can we have a look at this?

Changed in qemu:
status: New → Confirmed
summary: - kvm hangs at 100% cpu when connecting to forwarded ports
+ kvm hangs at 100% cpu when connecting to forwarded ports (when listed
+ incorrectly on the command line)
Revision history for this message
Dustin Kirkland  (kirkland) wrote :

At the very least, the manpage needs to be updated, as the "hostfwd=[tcp|udp]:[hostaddr]:hostport-[guestaddr]:guestport" section says: "This option can be given multiple times."

Revision history for this message
Dustin Kirkland  (kirkland) wrote :

The documentation aspect of this bug should be fix along with Bug #474969.

Changed in qemu-kvm (Ubuntu Lucid):
assignee: nobody → Brian Thomason (brian-thomason)
milestone: none → ubuntu-10.04-beta-1
Thierry Carrez (ttx)
Changed in qemu-kvm (Ubuntu Lucid):
milestone: ubuntu-10.04-beta-1 → none
Dustin Kirkland  (kirkland)
Changed in qemu-kvm (Ubuntu Lucid):
status: Confirmed → In Progress
assignee: Brian Thomason (brian-thomason) → Dustin Kirkland (kirkland)
Revision history for this message
Launchpad Janitor (janitor) wrote :

This bug was fixed in the package qemu-kvm - 0.12.3-0ubuntu6

---------------
qemu-kvm (0.12.3-0ubuntu6) lucid; urgency=low

  [ Dustin Kirkland ]
  * debian/postinst: clean up jaunty-era conffiles on upgrade, LP: #455411
  * debian/links, debian/qemu-kvm-extras.links: install non-x86 arch
    manpages in the qemu-kvm-extras package, LP: #478552

  [ Brian Thomason ]
  * debian/patches/better_describe_-net_options.patch: improve port
    forwarding documentation, LP: #474969, LP: #453617
 -- Dustin Kirkland <email address hidden> Fri, 05 Mar 2010 18:39:19 -0600

Changed in qemu-kvm (Ubuntu Lucid):
status: In Progress → Fix Released
Revision history for this message
Thomas Huth (th-huth) wrote :

Is there still an issue left here with upstream QEMU?

Changed in qemu:
status: Confirmed → Incomplete
Revision history for this message
Thomas Huth (th-huth) wrote :

There hasn't been any comment about upstream QEMU within the last months, so I assume this has been fixed there, too. Closing...

Changed in qemu:
status: Incomplete → Fix Released
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