Add support to debug unresponsive host

Add support to debug unresponsive host

[Jayanth Othayoth]

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## Problem Description
Issue #457:  Add support to debug unresponsive host.

Scope: High level design direction to solve this problem,

## Background and References
There are situation at customer places where OPAL/Linux goes unresponsive
causing a system hang. And there is no way to figure out what went wrong
with Linux kernel or OPAL. Looking for a way to trigger a dump capture on
Linux host so that we can capture the OS dump for post analysis.

## Proposed Design for POWER processor based systems:
Get all Host CPUs in reset vector and Linux then has a mechanism to patch
it into panic-kdump path to trigger dump capture. This will enable us to
analyze and fix customer issue where we see Linux hang and unresponsive
system.

### Redfish Schema used:
* Reference: DSP2046 2018.3,
* ComputerSystem 1.6.0 schema provides an action called
#ComputerSystem.Reset”, This action is used to reset the system. ResetType
parameter is used  for indicating type of reset need to be performed. In
this use case we can use “Nmi” type
    * Nmi: Generate a Diagnostic Interrupt (usually an NMI on x86 systems)
to cease normal operations, perform diagnostic actions and typically halt
the system.
* ### d-bus :

Option 1:   Extending  the existing  d-bus interface  state.Host  name
space (
/openbmc/phosphor-dbus-interfaces/xyz/openbmc_project/State/Host.interface.yaml
) to support new RequestedHostTransition property called  “Nmi”.   d-bus
backend can internally invoke processor specific target to do Sreset(
equivalent to x86 NMI) and associated  actions.

Option 2: Introducing new d-bus interface in the control.state namespace (
/openbmc/phosphor-dbus-interfaces/xyz/openbmc_project/Control/Host/NMI.interface.yaml)
namespace and implement the new d-bus back-end for respective  processor
specific targets.

## Alternatives Considered
NA

## Impacts:
NA

## Testing
NA

Looking for input from the team on this  High level design direction
approach.

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RE: Add support to debug unresponsive host

[Neeraj Ladkani]

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Some questions.


  1.  How does BMC know when to trigger NMI? Are we relying on agents to run and send heartbeat? Can this be done agentless ?
  2.  How do we NMI on non x86 platforms ?

we should brainstorm to create a generic framework to solve this problem.

What
Neeraj

From: openbmc <openbmc-bounces+neladk=microsoft.com@lists.ozlabs.org> On Behalf Of Jayanth Othayoth
Sent: Wednesday, May 15, 2019 5:40 AM
To: openbmc@lists.ozlabs.org; geissonator@gmail.com; bradleyb@fuzziesquirrel.com
Subject: Add support to debug unresponsive host

## Problem Description
Issue #457:  Add support to debug unresponsive host.

Scope: High level design direction to solve this problem,

## Background and References
There are situation at customer places where OPAL/Linux goes unresponsive causing a system hang. And there is no way to figure out what went wrong with Linux kernel or OPAL. Looking for a way to trigger a dump capture on Linux host so that we can capture the OS dump for post analysis.

## Proposed Design for POWER processor based systems:
Get all Host CPUs in reset vector and Linux then has a mechanism to patch it into panic-kdump path to trigger dump capture. This will enable us to analyze and fix customer issue where we see Linux hang and unresponsive system.

### Redfish Schema used:
* Reference: DSP2046 2018.3,
* ComputerSystem 1.6.0 schema provides an action called #ComputerSystem.Reset”, This action is used to reset the system. ResetType parameter is used  for indicating type of reset need to be performed. In this use case we can use “Nmi” type
    * Nmi: Generate a Diagnostic Interrupt (usually an NMI on x86 systems) to cease normal operations, perform diagnostic actions and typically halt the system. 

* ### d-bus :

Option 1:   Extending  the existing  d-bus interface  state.Host  name space ( /openbmc/phosphor-dbus-interfaces/xyz/openbmc_project/State/Host.interface.yaml ) to support new RequestedHostTransition property called  “Nmi”.   d-bus backend can internally invoke processor specific target to do Sreset( equivalent to x86 NMI) and associated  actions.

Option 2: Introducing new d-bus interface in the control.state namespace ( /openbmc/phosphor-dbus-interfaces/xyz/openbmc_project/Control/Host/NMI.interface.yaml) namespace and implement the new d-bus back-end for respective  processor specific targets.

## Alternatives Considered
NA

## Impacts:
NA

## Testing
NA

Looking for input from the team on this  High level design direction approach.

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Re: Add support to debug unresponsive host

[Artem Senichev]

We have solved a similar task for our VESNIN servers, based on POWER8 CPU
(OpenPOWER platform).

OpenBMC has pdbg debugger (meta-openpower/recipes-bsp/pdbg), this
utility, among other things, can be used to send SRESET signal from
OpenBMC to the host's CPU. As a result of handling the signal, host
side Linux kernel initiates kdump.

This procedure inevitably reboots the host system, whether the host
is working or the system is hung, so it is not a good idea to do this
automatically.
A system administrator initiates the procedure manually from OpenBMC
console.

-- 
Regards,
Artem Senichev
Software Engineer, YADRO.

On Wed, May 15, 2019 at 06:26:08PM +0000, Neeraj Ladkani wrote:
> Some questions.
> 
> 
>   1.  How does BMC know when to trigger NMI? Are we relying on agents to run and send heartbeat? Can this be done agentless ?
>   2.  How do we NMI on non x86 platforms ?
> 
> we should brainstorm to create a generic framework to solve this problem.
> 
> What
> Neeraj
> 
> From: openbmc <openbmc-bounces+neladk=microsoft.com@lists.ozlabs.org> On Behalf Of Jayanth Othayoth
> Sent: Wednesday, May 15, 2019 5:40 AM
> To: openbmc@lists.ozlabs.org; geissonator@gmail.com; bradleyb@fuzziesquirrel.com
> Subject: Add support to debug unresponsive host
> 
> ## Problem Description
> Issue #457:  Add support to debug unresponsive host.
> 
> Scope: High level design direction to solve this problem,
> 
> ## Background and References
> There are situation at customer places where OPAL/Linux goes unresponsive causing a system hang. And there is no way to figure out what went wrong with Linux kernel or OPAL. Looking for a way to trigger a dump capture on Linux host so that we can capture the OS dump for post analysis.
> 
> ## Proposed Design for POWER processor based systems:
> Get all Host CPUs in reset vector and Linux then has a mechanism to patch it into panic-kdump path to trigger dump capture. This will enable us to analyze and fix customer issue where we see Linux hang and unresponsive system.
> 
> ### Redfish Schema used:
> * Reference: DSP2046 2018.3,
> * ComputerSystem 1.6.0 schema provides an action called #ComputerSystem.Reset”, This action is used to reset the system. ResetType parameter is used  for indicating type of reset need to be performed. In this use case we can use “Nmi” type
>     * Nmi: Generate a Diagnostic Interrupt (usually an NMI on x86 systems) to cease normal operations, perform diagnostic actions and typically halt the system. 

> * ### d-bus :
> 
> Option 1:   Extending  the existing  d-bus interface  state.Host  name space ( /openbmc/phosphor-dbus-interfaces/xyz/openbmc_project/State/Host.interface.yaml ) to support new RequestedHostTransition property called  “Nmi”.   d-bus backend can internally invoke processor specific target to do Sreset( equivalent to x86 NMI) and associated  actions.
> 
> Option 2: Introducing new d-bus interface in the control.state namespace ( /openbmc/phosphor-dbus-interfaces/xyz/openbmc_project/Control/Host/NMI.interface.yaml) namespace and implement the new d-bus back-end for respective  processor specific targets.
> 
> ## Alternatives Considered
> NA
> 
> ## Impacts:
> NA
> 
> ## Testing
> NA
> 
> Looking for input from the team on this  High level design direction approach.

Re: Add support to debug unresponsive host

[Deepak Kodihalli]

On 15/05/19 6:09 PM, Jayanth Othayoth wrote:
> ## Problem Description
> Issue #457:  Add support to debug unresponsive host.
> 
> Scope: High level design direction to solve this problem,
> 
> ## Background and References
> There are situation at customer places where OPAL/Linux goes 
> unresponsive causing a system hang. And there is no way to figure out 
> what went wrong with Linux kernel or OPAL. Looking for a way to trigger 
> a dump capture on Linux host so that we can capture the OS dump for post 
> analysis.
> 
> ## Proposed Design for POWER processor based systems:
> Get all Host CPUs in reset vector and Linux then has a mechanism to 
> patch it into panic-kdump path to trigger dump capture. This will enable 
> us to analyze and fix customer issue where we see Linux hang and 
> unresponsive system.
> 
> ### Redfish Schema used:
> * Reference: DSP2046 2018.3,
> * ComputerSystem 1.6.0 schema provides an action called 
> #ComputerSystem.Reset”, This action is used to reset the system. 
> ResetType parameter is used  for indicating type of reset need to be 
> performed. In this use case we can use “Nmi” type
>      * Nmi: Generate a Diagnostic Interrupt (usually an NMI on x86 
> systems) to cease normal operations, perform diagnostic actions and 
> typically halt the system. 

> * ### d-bus :
> 
> Option 1:   Extending  the existing  d-bus interface  state.Host  name 
> space ( 
> /openbmc/phosphor-dbus-interfaces/xyz/openbmc_project/State/Host.interface.yaml 
> ) to support new RequestedHostTransition property called  “Nmi”.   d-bus 
> backend can internally invoke processor specific target to do Sreset( 
> equivalent to x86 NMI) and associated  actions.

I don't prefer this option, because this would mean adding host specific 
code in phoshor-state-manager, which I think until now is host agnostic. 
So for that reason, Option 2 sounds better. There are some good 
questions from Neeraj as well, so I would suggest adding this as a 
design template on Gerrit to gather better feedback.

Thanks,
Deepak

> Option 2: Introducing new d-bus interface in the control.state namespace 
> ( 
> /openbmc/phosphor-dbus-interfaces/xyz/openbmc_project/Control/Host/NMI.interface.yaml) 
> namespace and implement the new d-bus back-end for respective  processor 
> specific targets.

Re: Add support to debug unresponsive host

[Andrew Geissler]

On Thu, May 16, 2019 at 1:36 AM Deepak Kodihalli
<dkodihal@linux.vnet.ibm.com> wrote:
>
> On 15/05/19 6:09 PM, Jayanth Othayoth wrote:
> > ## Problem Description
> > Issue #457:  Add support to debug unresponsive host.
> >
> > Scope: High level design direction to solve this problem,
> >
> > ## Background and References
> > There are situation at customer places where OPAL/Linux goes
> > unresponsive causing a system hang. And there is no way to figure out
> > what went wrong with Linux kernel or OPAL. Looking for a way to trigger
> > a dump capture on Linux host so that we can capture the OS dump for post
> > analysis.
> >
> > ## Proposed Design for POWER processor based systems:
> > Get all Host CPUs in reset vector and Linux then has a mechanism to
> > patch it into panic-kdump path to trigger dump capture. This will enable
> > us to analyze and fix customer issue where we see Linux hang and
> > unresponsive system.
> >
> > ### Redfish Schema used:
> > * Reference: DSP2046 2018.3,
> > * ComputerSystem 1.6.0 schema provides an action called
> > #ComputerSystem.Reset”, This action is used to reset the system.
> > ResetType parameter is used  for indicating type of reset need to be
> > performed. In this use case we can use “Nmi” type
> >      * Nmi: Generate a Diagnostic Interrupt (usually an NMI on x86
> > systems) to cease normal operations, perform diagnostic actions and
> > typically halt the system.
> > * ### d-bus :
> >
> > Option 1:   Extending  the existing  d-bus interface  state.Host  name
> > space (
> > /openbmc/phosphor-dbus-interfaces/xyz/openbmc_project/State/Host.interface.yaml
> > ) to support new RequestedHostTransition property called  “Nmi”.   d-bus
> > backend can internally invoke processor specific target to do Sreset(
> > equivalent to x86 NMI) and associated  actions.
>
> I don't prefer this option, because this would mean adding host specific
> code in phoshor-state-manager, which I think until now is host agnostic.

Yeah, this was my main concern with tying it into phosphor-state-manager.
The fact Redfish put it in with their other state related commands (which
are implemented by phosphor-state-manager) is the only reason I'm a little
wishy-washy here. We could just create a generic systemd target "host-nmi"
or something and phosphor-state-manager could just call that to abstract
any of the specifics, but it sill doesn't really feel like it fits to me.

I think I prefer option 2, and then we can just map bmcweb to that API when
the Redfish command comes in. Sounds like for ppc64 systems we can just
use pdbg to issue the NMI.

> So for that reason, Option 2 sounds better. There are some good
> questions from Neeraj as well, so I would suggest adding this as a
> design template on Gerrit to gather better feedback.
>
> Thanks,
> Deepak
>
> > Option 2: Introducing new d-bus interface in the control.state namespace
> > (
> > /openbmc/phosphor-dbus-interfaces/xyz/openbmc_project/Control/Host/NMI.interface.yaml)
> > namespace and implement the new d-bus back-end for respective  processor
> > specific targets.
>

Re: Add support to debug unresponsive host

[Jayanth Othayoth]

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Design template Review is available here

https://gerrit.openbmc-project.xyz/c/openbmc/docs/+/21772

On Thu, May 16, 2019 at 6:31 PM Andrew Geissler <geissonator@gmail.com>
wrote:

> On Thu, May 16, 2019 at 1:36 AM Deepak Kodihalli
> <dkodihal@linux.vnet.ibm.com> wrote:
> >
> > On 15/05/19 6:09 PM, Jayanth Othayoth wrote:
> > > ## Problem Description
> > > Issue #457:  Add support to debug unresponsive host.
> > >
> > > Scope: High level design direction to solve this problem,
> > >
> > > ## Background and References
> > > There are situation at customer places where OPAL/Linux goes
> > > unresponsive causing a system hang. And there is no way to figure out
> > > what went wrong with Linux kernel or OPAL. Looking for a way to trigger
> > > a dump capture on Linux host so that we can capture the OS dump for
> post
> > > analysis.
> > >
> > > ## Proposed Design for POWER processor based systems:
> > > Get all Host CPUs in reset vector and Linux then has a mechanism to
> > > patch it into panic-kdump path to trigger dump capture. This will
> enable
> > > us to analyze and fix customer issue where we see Linux hang and
> > > unresponsive system.
> > >
> > > ### Redfish Schema used:
> > > * Reference: DSP2046 2018.3,
> > > * ComputerSystem 1.6.0 schema provides an action called
> > > #ComputerSystem.Reset”, This action is used to reset the system.
> > > ResetType parameter is used  for indicating type of reset need to be
> > > performed. In this use case we can use “Nmi” type
> > >      * Nmi: Generate a Diagnostic Interrupt (usually an NMI on x86
> > > systems) to cease normal operations, perform diagnostic actions and
> > > typically halt the system.
> > > * ### d-bus :
> > >
> > > Option 1:   Extending  the existing  d-bus interface  state.Host  name
> > > space (
> > >
> /openbmc/phosphor-dbus-interfaces/xyz/openbmc_project/State/Host.interface.yaml
> > > ) to support new RequestedHostTransition property called  “Nmi”.
>  d-bus
> > > backend can internally invoke processor specific target to do Sreset(
> > > equivalent to x86 NMI) and associated  actions.
> >
> > I don't prefer this option, because this would mean adding host specific
> > code in phoshor-state-manager, which I think until now is host agnostic.
>
> Yeah, this was my main concern with tying it into phosphor-state-manager.
> The fact Redfish put it in with their other state related commands (which
> are implemented by phosphor-state-manager) is the only reason I'm a little
> wishy-washy here. We could just create a generic systemd target "host-nmi"
> or something and phosphor-state-manager could just call that to abstract
> any of the specifics, but it sill doesn't really feel like it fits to me.
>
> I think I prefer option 2, and then we can just map bmcweb to that API when
> the Redfish command comes in. Sounds like for ppc64 systems we can just
> use pdbg to issue the NMI.
>
> > So for that reason, Option 2 sounds better. There are some good
> > questions from Neeraj as well, so I would suggest adding this as a
> > design template on Gerrit to gather better feedback.
> >
> > Thanks,
> > Deepak
> >
> > > Option 2: Introducing new d-bus interface in the control.state
> namespace
> > > (
> > >
> /openbmc/phosphor-dbus-interfaces/xyz/openbmc_project/Control/Host/NMI.interface.yaml)
> > > namespace and implement the new d-bus back-end for respective
> processor
> > > specific targets.
> >
>

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Re: Add support to debug unresponsive host

[vishwa]

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I kind of remember this topic being talked about in the past. Looks like 
we need to do 2 things prior to calling SRESET. I will comment the review.

!! Vishwa !!

On 5/27/19 12:45 PM, Jayanth Othayoth wrote:
> Design template Review is available here
>
> https://gerrit.openbmc-project.xyz/c/openbmc/docs/+/21772
>
> On Thu, May 16, 2019 at 6:31 PM Andrew Geissler <geissonator@gmail.com 
> <mailto:geissonator@gmail.com>> wrote:
>
>     On Thu, May 16, 2019 at 1:36 AM Deepak Kodihalli
>     <dkodihal@linux.vnet.ibm.com <mailto:dkodihal@linux.vnet.ibm.com>>
>     wrote:
>     >
>     > On 15/05/19 6:09 PM, Jayanth Othayoth wrote:
>     > > ## Problem Description
>     > > Issue #457:  Add support to debug unresponsive host.
>     > >
>     > > Scope: High level design direction to solve this problem,
>     > >
>     > > ## Background and References
>     > > There are situation at customer places where OPAL/Linux goes
>     > > unresponsive causing a system hang. And there is no way to
>     figure out
>     > > what went wrong with Linux kernel or OPAL. Looking for a way
>     to trigger
>     > > a dump capture on Linux host so that we can capture the OS
>     dump for post
>     > > analysis.
>     > >
>     > > ## Proposed Design for POWER processor based systems:
>     > > Get all Host CPUs in reset vector and Linux then has a
>     mechanism to
>     > > patch it into panic-kdump path to trigger dump capture. This
>     will enable
>     > > us to analyze and fix customer issue where we see Linux hang and
>     > > unresponsive system.
>     > >
>     > > ### Redfish Schema used:
>     > > * Reference: DSP2046 2018.3,
>     > > * ComputerSystem 1.6.0 schema provides an action called
>     > > #ComputerSystem.Reset”, This action is used to reset the system.
>     > > ResetType parameter is used  for indicating type of reset need
>     to be
>     > > performed. In this use case we can use “Nmi” type
>     > >      * Nmi: Generate a Diagnostic Interrupt (usually an NMI on x86
>     > > systems) to cease normal operations, perform diagnostic
>     actions and
>     > > typically halt the system.
>     > > * ### d-bus :
>     > >
>     > > Option 1:   Extending  the existing  d-bus interface 
>     state.Host  name
>     > > space (
>     > >
>     /openbmc/phosphor-dbus-interfaces/xyz/openbmc_project/State/Host.interface.yaml
>     > > ) to support new RequestedHostTransition property called 
>     “Nmi”.   d-bus
>     > > backend can internally invoke processor specific target to do
>     Sreset(
>     > > equivalent to x86 NMI) and associated  actions.
>     >
>     > I don't prefer this option, because this would mean adding host
>     specific
>     > code in phoshor-state-manager, which I think until now is host
>     agnostic.
>
>     Yeah, this was my main concern with tying it into
>     phosphor-state-manager.
>     The fact Redfish put it in with their other state related commands
>     (which
>     are implemented by phosphor-state-manager) is the only reason I'm
>     a little
>     wishy-washy here. We could just create a generic systemd target
>     "host-nmi"
>     or something and phosphor-state-manager could just call that to
>     abstract
>     any of the specifics, but it sill doesn't really feel like it fits
>     to me.
>
>     I think I prefer option 2, and then we can just map bmcweb to that
>     API when
>     the Redfish command comes in. Sounds like for ppc64 systems we can
>     just
>     use pdbg to issue the NMI.
>
>     > So for that reason, Option 2 sounds better. There are some good
>     > questions from Neeraj as well, so I would suggest adding this as a
>     > design template on Gerrit to gather better feedback.
>     >
>     > Thanks,
>     > Deepak
>     >
>     > > Option 2: Introducing new d-bus interface in the control.state
>     namespace
>     > > (
>     > >
>     /openbmc/phosphor-dbus-interfaces/xyz/openbmc_project/Control/Host/NMI.interface.yaml)
>     > > namespace and implement the new d-bus back-end for respective 
>     processor
>     > > specific targets.
>     >
>

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