[Qemu-devel] [Bug 453617] Re: kvm hangs at 100% cpu when connecting to forwarded ports (when listed incorrectly on the command line)

[Qemu-devel] [Bug 453617] Re: kvm hangs at 100% cpu when connecting to forwarded ports (when listed incorrectly on the command line)

[Launchpad Bug Tracker]

** Branch linked: lp:ubuntu/qemu-kvm

-- 
kvm hangs at 100% cpu when connecting to forwarded ports (when listed incorrectly on the command line)
https://bugs.launchpad.net/bugs/453617
You received this bug notification because you are a member of qemu-
devel-ml, which is subscribed to QEMU.

Status in QEMU: Confirmed
Status in “qemu-kvm” package in Ubuntu: Fix Released
Status in “qemu-kvm” source package in Lucid: Fix Released

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

Re: [Qemu-devel] [Bug 453617] Re: kvm hangs at 100% cpu when connecting to forwarded ports (when listed incorrectly on the command line)

[Gleb Natapov]

> ProblemType: Bug
> Architecture: amd64
> Date: Fri Oct 16 17:19:59 2009
> DistroRelease: Ubuntu 9.10
What is the point forwarding distro bugs here? Can we have upstream bug
tracker to report upstream issues?

--
			Gleb.

Re: [Qemu-devel] [Bug 453617] Re: kvm hangs at 100% cpu when connecting to forwarded ports (when listed incorrectly on the command line)

[Michael Tokarev]

21.05.2010 19:42, Gleb Natapov wrote:
>> ProblemType: Bug
>> Architecture: amd64
>> Date: Fri Oct 16 17:19:59 2009
>> DistroRelease: Ubuntu 9.10
> What is the point forwarding distro bugs here? Can we have upstream bug
> tracker to report upstream issues?

Um, this _is_ upstream issue, as far as I can see.
It exists in qemu-kvm-0.12.4 at least, I just verified.

What's wrong with that forwarding?

/mjt

[Qemu-devel] Re: [Bug 453617] Re: kvm hangs at 100% cpu when connecting to forwarded ports (when listed incorrectly on the command line)

[Jan Kiszka]

Michael Tokarev wrote:
> 21.05.2010 19:42, Gleb Natapov wrote:
>>> ProblemType: Bug
>>> Architecture: amd64
>>> Date: Fri Oct 16 17:19:59 2009
>>> DistroRelease: Ubuntu 9.10
>> What is the point forwarding distro bugs here? Can we have upstream bug
>> tracker to report upstream issues?
> 
> Um, this _is_ upstream issue, as far as I can see.
> It exists in qemu-kvm-0.12.4 at least, I just verified.

Well, this particular bug rather looks like a potential documentation
insufficiency:

Instantiating two user space networking stacks on the _same_ vlan with
_identical_ parameters is just asking for troubles. If the reporter read
the manual and then did the mistake, we may have to clarify the docs
what "-net user" does.

> 
> What's wrong with that forwarding?

IMHO so far nothing - as long as the ratio of pure downstream issues
remains low. I think we should give this channel a chance as it can be
advantageous to have more "real" end-user reports.

Jan

-- 
Siemens AG, Corporate Technology, CT T DE IT 1
Corporate Competence Center Embedded Linux

[Qemu-devel] Re: [Bug 453617] Re: kvm hangs at 100% cpu when connecting to forwarded ports (when listed incorrectly on the command line)

[Michael Tokarev]

21.05.2010 21:16, Jan Kiszka wrote:
> Michael Tokarev wrote:
>> 21.05.2010 19:42, Gleb Natapov wrote:
>>>> ProblemType: Bug
>>>> Architecture: amd64
>>>> Date: Fri Oct 16 17:19:59 2009
>>>> DistroRelease: Ubuntu 9.10
>>> What is the point forwarding distro bugs here? Can we have upstream bug
>>> tracker to report upstream issues?
>>
>> Um, this _is_ upstream issue, as far as I can see.
>> It exists in qemu-kvm-0.12.4 at least, I just verified.
>
> Well, this particular bug rather looks like a potential documentation
> insufficiency:
>
> Instantiating two user space networking stacks on the _same_ vlan with
> _identical_ parameters is just asking for troubles. If the reporter read
> the manual and then did the mistake, we may have to clarify the docs
> what "-net user" does.

Actually it's solved like that in ubuntu, by updating documentation.

It's a common trap - two pairs of -net nic -net tap without
specifying vlan=NN and voila, you have a loop on your network.
This has been tried/trapped on more than once, that's for sure :)

>> What's wrong with that forwarding?
>
> IMHO so far nothing - as long as the ratio of pure downstream issues
> remains low. I think we should give this channel a chance as it can be
> advantageous to have more "real" end-user reports.

There's very few distro-specific bugreports usually.  At least on
Debian.  Two observations: I forward or notify about bugs filed
against Debian package (I maintain qemu-kvm there) anyway, and
quite some bugs filed actually are either usage/operator errors
or sort of misunderstanding or misuse, not real bugs.

But actually I were asking about this particular bugreport,
not about general forwarding - which - at least - should be
done with care :)

Thanks!

/mjt

[Qemu-devel] Re: [Bug 453617] Re: kvm hangs at 100% cpu when connecting to forwarded ports (when listed incorrectly on the command line)

[Jan Kiszka]

Michael Tokarev wrote:
> 21.05.2010 21:16, Jan Kiszka wrote:
>> Michael Tokarev wrote:
>>> 21.05.2010 19:42, Gleb Natapov wrote:
>>>>> ProblemType: Bug
>>>>> Architecture: amd64
>>>>> Date: Fri Oct 16 17:19:59 2009
>>>>> DistroRelease: Ubuntu 9.10
>>>> What is the point forwarding distro bugs here? Can we have upstream bug
>>>> tracker to report upstream issues?
>>> Um, this _is_ upstream issue, as far as I can see.
>>> It exists in qemu-kvm-0.12.4 at least, I just verified.
>> Well, this particular bug rather looks like a potential documentation
>> insufficiency:
>>
>> Instantiating two user space networking stacks on the _same_ vlan with
>> _identical_ parameters is just asking for troubles. If the reporter read
>> the manual and then did the mistake, we may have to clarify the docs
>> what "-net user" does.
> 
> Actually it's solved like that in ubuntu, by updating documentation.
> 
> It's a common trap - two pairs of -net nic -net tap without
> specifying vlan=NN and voila, you have a loop on your network.
> This has been tried/trapped on more than once, that's for sure :)

So, in the presence of -netdev, we may have to deemphasize on -net which
is now actually an expert knob. Doc updates welcome where required.

> 
>>> What's wrong with that forwarding?
>> IMHO so far nothing - as long as the ratio of pure downstream issues
>> remains low. I think we should give this channel a chance as it can be
>> advantageous to have more "real" end-user reports.
> 
> There's very few distro-specific bugreports usually.  At least on
> Debian.  Two observations: I forward or notify about bugs filed
> against Debian package (I maintain qemu-kvm there) anyway, and
> quite some bugs filed actually are either usage/operator errors
> or sort of misunderstanding or misuse, not real bugs.

If there are too much operator errors, that may actually point to some
usability and/or documentation issue.

> 
> But actually I were asking about this particular bugreport,
> not about general forwarding - which - at least - should be
> done with care :)

Right.

Jan

-- 
Siemens AG, Corporate Technology, CT T DE IT 1
Corporate Competence Center Embedded Linux

[Qemu-devel] Re: [Bug 453617] Re: kvm hangs at 100% cpu when connecting to forwarded ports (when listed incorrectly on the command line)

[Gleb Natapov]

On Fri, May 21, 2010 at 09:22:23PM +0400, Michael Tokarev wrote:
> But actually I were asking about this particular bugreport,
> not about general forwarding - which - at least - should be
> done with care :)
> 
Ugh, I am talking about general forwarding not this particular bug
report :) Although it was not clear to me from the message that distro
maintainers actually looked at the report and verified it against
upstream.

--
			Gleb.

[Qemu-devel] Re: [Bug 453617] Re: kvm hangs at 100% cpu when connecting to forwarded ports (when listed incorrectly on the command line)

[Jan Kiszka]

Jan Kiszka wrote:
> Michael Tokarev wrote:
>> 21.05.2010 19:42, Gleb Natapov wrote:
>>>> ProblemType: Bug
>>>> Architecture: amd64
>>>> Date: Fri Oct 16 17:19:59 2009
>>>> DistroRelease: Ubuntu 9.10
>>> What is the point forwarding distro bugs here? Can we have upstream bug
>>> tracker to report upstream issues?
>> Um, this _is_ upstream issue, as far as I can see.
>> It exists in qemu-kvm-0.12.4 at least, I just verified.
> 
> Well, this particular bug rather looks like a potential documentation
> insufficiency:
> 
> Instantiating two user space networking stacks on the _same_ vlan with
> _identical_ parameters is just asking for troubles. If the reporter read
> the manual and then did the mistake, we may have to clarify the docs
> what "-net user" does.
> 
>> What's wrong with that forwarding?
> 
> IMHO so far nothing - as long as the ratio of pure downstream issues
> remains low. I think we should give this channel a chance as it can be
> advantageous to have more "real" end-user reports.

That said, initial reports may show up here, but we do need some filter
to sort out distro-specific updates - like this one.

Jan

-- 
Siemens AG, Corporate Technology, CT T DE IT 1
Corporate Competence Center Embedded Linux

Re: [Qemu-devel] [Bug 453617] Re: kvm hangs at 100% cpu when connecting to forwarded ports (when listed incorrectly on the command line)

[Gleb Natapov]

On Fri, May 21, 2010 at 08:31:41PM +0400, Michael Tokarev wrote:
> 21.05.2010 19:42, Gleb Natapov wrote:
> >>ProblemType: Bug
> >>Architecture: amd64
> >>Date: Fri Oct 16 17:19:59 2009
> >>DistroRelease: Ubuntu 9.10
> >What is the point forwarding distro bugs here? Can we have upstream bug
> >tracker to report upstream issues?
> 
> Um, this _is_ upstream issue, as far as I can see.
So bug report should be marked as upstream issue and not distro package
bug. Then it will be clear that distro maintainers looked at the bug and
determined it to be upstream issue.

> It exists in qemu-kvm-0.12.4 at least, I just verified.
> 
Then fill bug report against upstream.

> What's wrong with that forwarding?
> 
Do we want every Ubuntu bug report about qemu/qemu-kvm automatically
forwarded to mailing list?

--
			Gleb.

Re: [Qemu-devel] [Bug 453617] Re: kvm hangs at 100% cpu when connecting to forwarded ports (when listed incorrectly on the command line)

[Anthony Liguori]

On 05/21/2010 10:42 AM, Gleb Natapov wrote:
>> ProblemType: Bug
>> Architecture: amd64
>> Date: Fri Oct 16 17:19:59 2009
>> DistroRelease: Ubuntu 9.10
>>      
> What is the point forwarding distro bugs here? Can we have upstream bug
> tracker to report upstream issues?
>    

These bugs are being explicitly reported against upstream.  Launchpad 
can also track status against distros bugs (Fedora, Debian, Gentoo, 
Ubuntu, etc.).

It can be annoying is if a very Ubuntu (or other distribution) specific 
bug report is marked also affects upstream without a clear indication 
that this was in fact explicitly tested against upstream (and what 
specific version was tested).  This is something that we can fix though 
by just making protocol clear for this type of thing.

Regards,

Anthony Liguori


> --
> 			Gleb.
>
>    

Re: [Qemu-devel] [Bug 453617] Re: kvm hangs at 100% cpu when connecting to forwarded ports (when listed incorrectly on the command line)

[Gleb Natapov]

On Fri, May 21, 2010 at 02:23:13PM -0500, Anthony Liguori wrote:
> On 05/21/2010 10:42 AM, Gleb Natapov wrote:
> >>ProblemType: Bug
> >>Architecture: amd64
> >>Date: Fri Oct 16 17:19:59 2009
> >>DistroRelease: Ubuntu 9.10
> >What is the point forwarding distro bugs here? Can we have upstream bug
> >tracker to report upstream issues?
> 
> These bugs are being explicitly reported against upstream.
How should we know it from the message?

> Launchpad can also track status against distros bugs (Fedora,
> Debian, Gentoo, Ubuntu, etc.).
> 
Great, here we only care about upstream.

> It can be annoying is if a very Ubuntu (or other distribution)
> specific bug report is marked also affects upstream without a clear
> indication that this was in fact explicitly tested against upstream
> (and what specific version was tested).  This is something that we
> can fix though by just making protocol clear for this type of thing.
> 
New bug should be opened against upstream. Then it will be crystal
clear that somebody took the time to check against upstream.

--
			Gleb.

Re: [Qemu-devel] [Bug 453617] Re: kvm hangs at 100% cpu when connecting to forwarded ports (when listed incorrectly on the command line)

[Gleb Natapov]

Another thing. If my memory serves me right it was promised that message
will contain enough info to contact bug reporter without going through
launchpad web interface. In other words email of bug reporter will be
specified. I can't find it in the message.

--
			Gleb.

Re: [Qemu-devel] [Bug 453617] Re: kvm hangs at 100% cpu when connecting to forwarded ports (when listed incorrectly on the command line)

[Anthony Liguori]

On 05/21/2010 02:37 PM, Gleb Natapov wrote:
> Another thing. If my memory serves me right it was promised that message
> will contain enough info to contact bug reporter without going through
> launchpad web interface. In other words email of bug reporter will be
> specified. I can't find it in the message.
>    

It is when the bug is original filed against the upstream project.

I think what you're suggesting is that bugs filed against a distro (say 
Ubuntu) should not just be marked as "also affects upstream" but rather 
that a new upstream bug should be filed.  It's still possible to connect 
the two bugs and I think it's not an unreasonable suggestion.

Regards,

Anthony Liguori

> --
> 			Gleb.
>    

Re: [Qemu-devel] [Bug 453617] Re: kvm hangs at 100% cpu when connecting to forwarded ports (when listed incorrectly on the command line)

[Gleb Natapov]

On Fri, May 21, 2010 at 02:44:46PM -0500, Anthony Liguori wrote:
> On 05/21/2010 02:37 PM, Gleb Natapov wrote:
> >Another thing. If my memory serves me right it was promised that message
> >will contain enough info to contact bug reporter without going through
> >launchpad web interface. In other words email of bug reporter will be
> >specified. I can't find it in the message.
> 
> It is when the bug is original filed against the upstream project.
> 
> I think what you're suggesting is that bugs filed against a distro
> (say Ubuntu) should not just be marked as "also affects upstream"
> but rather that a new upstream bug should be filed.  It's still
> possible to connect the two bugs and I think it's not an
> unreasonable suggestion.
> 
Correct, thanks.

--
			Gleb.

[Qemu-devel] [Bug 453617] Re: kvm hangs at 100% cpu when connecting to forwarded ports (when listed incorrectly on the command line)

[Thomas Huth]

Is there still an issue left here with upstream QEMU?

** Changed in: qemu
       Status: Confirmed => Incomplete

-- 
You received this bug notification because you are a member of qemu-
devel-ml, which is subscribed to QEMU.
https://bugs.launchpad.net/bugs/453617

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

Status in QEMU:
  Incomplete
Status in qemu-kvm package in Ubuntu:
  Fix Released
Status in qemu-kvm source package in Lucid:
  Fix Released

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

To manage notifications about this bug go to:
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[Qemu-devel] [Bug 453617] Re: kvm hangs at 100% cpu when connecting to forwarded ports (when listed incorrectly on the command line)

[Thomas Huth]

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

-- 
You received this bug notification because you are a member of qemu-
devel-ml, which is subscribed to QEMU.
https://bugs.launchpad.net/bugs/453617

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

Status in QEMU:
  Fix Released
Status in qemu-kvm package in Ubuntu:
  Fix Released
Status in qemu-kvm source package in Lucid:
  Fix Released

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

To manage notifications about this bug go to:
https://bugs.launchpad.net/qemu/+bug/453617/+subscriptions