[gentoo-user] app-admin/mcelog daily cronjob?

[gentoo-user] app-admin/mcelog daily cronjob?

[Stroller]

I set up a new machine a couple of months ago, and for some time I've been getting an email each day:

  Subject: Cron <root@host> test -x /usr/sbin/run-crons && /usr/sbin/run-crons
  fopen: Permission denied


Taking a look at /etc/cron.daily/ shows only one odd one out:

  $ sudo ls -lh /etc/cron.daily/
  total 16K  
  -rwxr-xr-x 1 root root  180 Feb  4 20:28 logrotate
  -rwxr-xr-x 1 root root  196 Mar  3 09:48 man-db
  -rw-r--r-- 1 root root  141 Apr 16 14:09 mcelog  
  -rwxr-xr-x 1 root root 1.3K Feb  4 23:53 mlocate


I *assume* that mcelog is the cron job which is causing this error, although the error message is not much to go on. It doesn't have execute permissions set, though, so that's what leads me towards this (tentative) conclusion.

I dunno, running it manually gives a different error:

  $ sudo /etc/cron.daily/mcelog
  sudo: /etc/cron.daily/mcelog: command not found
  $ 

Nevertheless, when I look at the http://mcelog.org/ homepage, specified in the package description, it says:

  Traditionally mcelog was run as a cronjob, but this usage is
  deprecated now. The modern way to run it is to start it at
  boot up time and run it always as a daemon.

I tried unmerging app-admin/mcelog and the cron.daily file is removed; then remerging (the latest stable version - 1.0_pre3_p20130621-r1) and it's reinstalled with the same permissions.

So I guess my question is: is this a bug with the app-admin/mcelog package?

I've got another system which isn't showing this problem, and mcelog is not installed. And the system *seems* to be running just fine, despite the assertion at mcelog.or that "mcelog is required by … Linux kernels … to log machine checks and should run on all Linux systems that need error handling." 

On the system which is showing this problem, app-admin/mcelog is in the world file - and it was before I started investigating this problem (I know this because I have a clone of that system which I took a few weeks ago), although I don't recall ever choosing to install it. 

What is mcelog, and why do I need it, please?

Stroller.

Re: [gentoo-user] app-admin/mcelog daily cronjob?

[Tom Wijsman]

On Wed, 16 Apr 2014 14:39:16 +0100
Stroller <stroller@stellar.eclipse.co.uk> wrote:

> What is mcelog, and why do I need it, please?

Machine check exception logger; iotw, it logs hardware errors.

-- 
With kind regards,

Tom Wijsman (TomWij)
Gentoo Developer

E-mail address  : TomWij@gentoo.org
GPG Public Key  : 6D34E57D
GPG Fingerprint : C165 AF18 AB4C 400B C3D2  ABF0 95B2 1FCD 6D34 E57D

Re: [gentoo-user] app-admin/mcelog daily cronjob?

[Stroller]

On Wed, 16 April 2014, at 3:44 pm, Tom Wijsman <TomWij@gentoo.org> wrote:

> On Wed, 16 Apr 2014 14:39:16 +0100
> Stroller <stroller@stellar.eclipse.co.uk> wrote:
> 
>> What is mcelog, and why do I need it, please?
> 
> Machine check exception logger; iotw, it logs hardware errors.

Ok, ignoring everything else that I wrote in my previous message, that this package appears to be generating daily errors… 

your contention is that I don't need it, because my other machine is running fine without it?

Stroller.

Re: [gentoo-user] app-admin/mcelog daily cronjob?

[Tom Wijsman]

On Wed, 16 Apr 2014 16:39:22 +0100
Stroller <stroller@stellar.eclipse.co.uk> wrote:

> 
> On Wed, 16 April 2014, at 3:44 pm, Tom Wijsman <TomWij@gentoo.org>
> wrote:
> 
> > On Wed, 16 Apr 2014 14:39:16 +0100
> > Stroller <stroller@stellar.eclipse.co.uk> wrote:
> > 
> >> What is mcelog, and why do I need it, please?
> > 
> > Machine check exception logger; iotw, it logs hardware errors.
> 
> Ok, ignoring everything else that I wrote in my previous message,
> that this package appears to be generating daily errors… 
> 
> your contention is that I don't need it, because my other machine is
> running fine without it?

There is no such indication in that reply. That is up to you to decide.

-- 
With kind regards,

Tom Wijsman (TomWij)
Gentoo Developer

E-mail address  : TomWij@gentoo.org
GPG Public Key  : 6D34E57D
GPG Fingerprint : C165 AF18 AB4C 400B C3D2  ABF0 95B2 1FCD 6D34 E57D

Re: [gentoo-user] app-admin/mcelog daily cronjob?

[Stroller]

On Wed, 16 April 2014, at 4:52 pm, Tom Wijsman <TomWij@gentoo.org> wrote:
> 
> There is no such indication in that reply. That is up to you to decide.

Well, I posted here looking for useful answers and perhaps a full explanation (like, of how this is needed beyond the system logger), not vapid one-liners. 

I guess I'll just file a vapid-one bug that my Gentoo system is generating these cron messages, rather than first trying to come to a understanding of the cause. Would that make the developers' lives easier? 

Stroller.

Re: [gentoo-user] app-admin/mcelog daily cronjob?

[Alan McKinnon]

On 16/04/2014 18:14, Stroller wrote:
> 
> On Wed, 16 April 2014, at 4:52 pm, Tom Wijsman <TomWij@gentoo.org> wrote:
>>
>> There is no such indication in that reply. That is up to you to decide.
> 
> Well, I posted here looking for useful answers and perhaps a full explanation (like, of how this is needed beyond the system logger), not vapid one-liners. 
> 
> I guess I'll just file a vapid-one bug that my Gentoo system is generating these cron messages, rather than first trying to come to a understanding of the cause. Would that make the developers' lives easier? 
> 
> Stroller.
> 
> 
> 
> 


mce is Machine Check Exception; it's a hardware trickery that watches
for and records faults in hardware.

Consider something like Dell's fancy monitoring softwares, the results
don't magically appear in syslog - you use Dell's client app to query
the hardware, figure out what the bits means then you can look-see what
is going on. mcelog is sort of in the same class of software, but it's a
generic interface.

You don't *have* to use it, the machines will run just fine without it.
You will lack some monitoring though that could be useful - that's your
call.

As for the cron job files, by all means file a bug. At a minimum you'll
get an answer as to what the dev thinks about that deprecation status.

-- 
Alan McKinnon
alan.mckinnon@gmail.com

Re: [gentoo-user] app-admin/mcelog daily cronjob?

[Tom Wijsman]

On Wed, 16 Apr 2014 17:14:27 +0100
Stroller <stroller@stellar.eclipse.co.uk> wrote:

> 
> On Wed, 16 April 2014, at 4:52 pm, Tom Wijsman <TomWij@gentoo.org>
> wrote:
> > 
> > There is no such indication in that reply. That is up to you to
> > decide.
> 
> Well, I posted here looking for useful answers

You need it when you need it; iotw, what keeps you from your decision?

(http://blog.stackoverflow.com/2010/11/qa-is-hard-lets-go-shopping/)

> and perhaps a full explanation (like, of how this is needed beyond
> the system logger), not vapid one-liners. 

For a system to log a source it needs a logger that logs that source.

> I guess I'll just file a vapid-one bug that my Gentoo system is
> generating these cron messages, rather than first trying to come to a
> understanding of the cause. Would that make the developers' lives
> easier? 

If it is a bug to you, up to you to decide, then feel free to file it.

-- 
With kind regards,

Tom Wijsman (TomWij)
Gentoo Developer

E-mail address  : TomWij@gentoo.org
GPG Public Key  : 6D34E57D
GPG Fingerprint : C165 AF18 AB4C 400B C3D2  ABF0 95B2 1FCD 6D34 E57D

Re: [gentoo-user] app-admin/mcelog daily cronjob?

[Randy Barlow]

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On Wed, 16 Apr 2014 14:39:16 +0100
Stroller <stroller@stellar.eclipse.co.uk> wrote:
> Taking a look at /etc/cron.daily/ shows only one odd one out:
> 
>   $ sudo ls -lh /etc/cron.daily/
>   total 16K  
>   -rwxr-xr-x 1 root root  180 Feb  4 20:28 logrotate
>   -rwxr-xr-x 1 root root  196 Mar  3 09:48 man-db
>   -rw-r--r-- 1 root root  141 Apr 16 14:09 mcelog  
>   -rwxr-xr-x 1 root root 1.3K Feb  4 23:53 mlocate

I don't think cron will attempt to execute anything in cron.daily that doesn't have execute perms, so the error probably isn't coming from mcelog.

-- 
Randy Barlow <randy@electronsweatshop.com>

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Re: [gentoo-user] app-admin/mcelog daily cronjob?

[Neil Bothwick]

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On Wed, 16 Apr 2014 14:39:16 +0100, Stroller wrote:

> Nevertheless, when I look at the http://mcelog.org/ homepage, specified
> in the package description, it says:
> 
>   Traditionally mcelog was run as a cronjob, but this usage is
>   deprecated now. The modern way to run it is to start it at
>   boot up time and run it always as a daemon.
> 
> I tried unmerging app-admin/mcelog and the cron.daily file is removed;
> then remerging (the latest stable version - 1.0_pre3_p20130621-r1) and
> it's reinstalled with the same permissions.
> 
> So I guess my question is: is this a bug with the app-admin/mcelog
> package?

I don't think so. If the running via cron is possible but deprecated,
proving a cron script with execute permissions disabled seems a sensible
way of covering both options.

As mcelog is not critical, why not try unmerging it for a couple of days
to see whether the messages disappear?


-- 
Neil Bothwick

New sig wanted good price paid.

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Re: [gentoo-user] app-admin/mcelog daily cronjob?

[Stroller]

On Wed, 16 April 2014, at 5:41 pm, Tom Wijsman <TomWij@gentoo.org> wrote:
> ...
>> I guess I'll just file a vapid-one bug that my Gentoo system is
>> generating these cron messages, rather than first trying to come to a
>> understanding of the cause. Would that make the developers' lives
>> easier? 
> 
> If it is a bug to you, up to you to decide, then feel free to file it.

Do you seriously consider it up for debate whether or not it's a bug, when daily error messages are produced and emailed to the system admin?

Stroller.

Re: [gentoo-user] app-admin/mcelog daily cronjob?

[Stroller]

On Thu, 17 April 2014, at 9:49 am, Neil Bothwick <neil@digimed.co.uk> wrote:
>> ...
>> So I guess my question is: is this a bug with the app-admin/mcelog
>> package?
> 
> I don't think so. If the running via cron is possible but deprecated,
> proving a cron script with execute permissions disabled seems a sensible
> way of covering both options.

If this is the cause I would assume that everybody would be seeing the same error message. 

I'm pretty sure a cron USE flag is in use elsewhere, I think it would be better to have an option to install the package without the cron script, rather than having to delete it manually each time one upgrades the package.

USE=-cron will persist throughout updates, if it's set in make.conf or package.use.

> As mcelog is not critical, why not try unmerging it for a couple of days
> to see whether the messages disappear?

Will do.

Stroller.

Re: [gentoo-user] app-admin/mcelog daily cronjob?

[Neil Bothwick]

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On Thu, 17 Apr 2014 13:15:57 +0100, Stroller wrote:

> On Thu, 17 April 2014, at 9:49 am, Neil Bothwick <neil@digimed.co.uk>
> wrote:
> >> ...
> >> So I guess my question is: is this a bug with the app-admin/mcelog
> >> package?  
> > 
> > I don't think so. If the running via cron is possible but deprecated,
> > proving a cron script with execute permissions disabled seems a
> > sensible way of covering both options.  
> 
> If this is the cause I would assume that everybody would be seeing the
> same error message. 

That assumes that everybody has mcelog installed, they don't. It doesn't
even seem certain that this script is causing the problem. Apart fro
whether or not the cron script is actually run, upstream considers running
via cron deprecated, not broken, so including a cron script is perfectly
valid for now.

> I'm pretty sure a cron USE flag is in use elsewhere, I think it would
> be better to have an option to install the package without the cron
> script, rather than having to delete it manually each time one upgrades
> the package.

That's a fair point, except you don't have to delete anything. If the
execute permission is not set, the script does not run.

> USE=-cron will persist throughout updates, if it's set in make.conf or
> package.use.

It may be worth filing a bug requesting the use of that flag.


-- 
Neil Bothwick

If it ain't broke, break it and charge for repair.

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Re: [gentoo-user] app-admin/mcelog daily cronjob?

[Tom Wijsman]

On Thu, 17 Apr 2014 13:11:38 +0100
Stroller <stroller@stellar.eclipse.co.uk> wrote:

> 
> On Wed, 16 April 2014, at 5:41 pm, Tom Wijsman <TomWij@gentoo.org>
> wrote:
> > ...
> >> I guess I'll just file a vapid-one bug that my Gentoo system is
> >> generating these cron messages, rather than first trying to come
> >> to a understanding of the cause. Would that make the developers'
> >> lives easier? 
> > 
> > If it is a bug to you, up to you to decide, then feel free to file
> > it.
> 
> Do you seriously consider it up for debate whether or not it's a bug,
> when daily error messages are produced and emailed to the system
> admin?

That depends on whether you consider that to be the expected behavior
for the way it has been set up; the cause is already known, wrong perms.

Would filing a bug make your life easier? Do you want me to file a bug?

-- 
With kind regards,

Tom Wijsman (TomWij)
Gentoo Developer

E-mail address  : TomWij@gentoo.org
GPG Public Key  : 6D34E57D
GPG Fingerprint : C165 AF18 AB4C 400B C3D2  ABF0 95B2 1FCD 6D34 E57D

Re: [gentoo-user] app-admin/mcelog daily cronjob?

[Stroller]

On Thu, 17 April 2014, at 2:32 pm, Tom Wijsman <TomWij@gentoo.org> wrote:
>> ...
>> Do you seriously consider it up for debate whether or not it's a bug,
>> when daily error messages are produced and emailed to the system
>> admin?
> 
> That depends on whether you consider that to be the expected behavior
> for the way it has been set up; the cause is already known, wrong perms.

Well, it seems to be the Gentoo devs that set it up this way.

You're the expert - you tell me why this is happening.

You haven't given me any explanation why this package is on a freshly-installed Gentoo system, you haven't told me in the Gentoo install docs that I need to configure this package, have you?

Stroller.

Re: [gentoo-user] app-admin/mcelog daily cronjob?

[Stroller]

On Thu, 17 April 2014, at 1:28 pm, Neil Bothwick <neil@digimed.co.uk> wrote:
> On Thu, 17 Apr 2014 13:15:57 +0100, Stroller wrote:
>> ...
>> If this is the cause I would assume that everybody would be seeing the
>> same error message. 
> 
> That assumes that everybody has mcelog installed, they don't.

Since I don't recall installing it, I assume that this is now being shipped as part of world.

So, yes, I would expect a lot of people to be seeing the problem.

> ...
>> I'm pretty sure a cron USE flag is in use elsewhere, I think it would
>> be better to have an option to install the package without the cron
>> script, rather than having to delete it manually each time one upgrades
>> the package.
> 
> That's a fair point, except you don't have to delete anything. If the
> execute permission is not set, the script does not run.

I think it's reasonable not to expect a daily error message from default settings which the user hasn't been advised to configure. 

I don't know whether the script is being run or not, but assuming this package is causing this error message (which is the assumption under which you made this reply), the error is being produced. 

Stroller.

Re: [gentoo-user] app-admin/mcelog daily cronjob?

[Neil Bothwick]

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On Thu, 17 Apr 2014 18:17:35 +0100, Stroller wrote:

> > That assumes that everybody has mcelog installed, they don't.  
> 
> Since I don't recall installing it, I assume that this is now being
> shipped as part of world.

It's no t on anything here. @world is empty, I take it you mean @system.
That is defined by the current profile so if it had been added, anyone
running the latest profile would have it - I am and I do not.

If it's in @world, you put it there.

> >> I'm pretty sure a cron USE flag is in use elsewhere, I think it would
> >> be better to have an option to install the package without the cron
> >> script, rather than having to delete it manually each time one
> >> upgrades the package.  
> > 
> > That's a fair point, except you don't have to delete anything. If the
> > execute permission is not set, the script does not run.  
> 
> I think it's reasonable not to expect a daily error message from
> default settings which the user hasn't been advised to configure. 
> 
> I don't know whether the script is being run or not, but assuming this
> package is causing this error message (which is the assumption under
> which you made this reply), the error is being produced. 

I'm only following on from your assumption. I see no reason why a
disabled cron script should cause an error message, but it's your system
and you know enough for me to follow your judgement. If you are still
uncertain what is causing the messages, surely finding out must be your
priority.


-- 
Neil Bothwick

Don't take life too seriously, you won't get out alive.

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Re: [gentoo-user] app-admin/mcelog daily cronjob?

[Tom Wijsman]

On Thu, 17 Apr 2014 18:13:57 +0100
Stroller <stroller@stellar.eclipse.co.uk> wrote:

> 
> On Thu, 17 April 2014, at 2:32 pm, Tom Wijsman <TomWij@gentoo.org>
> wrote:
> >> ...
> >> Do you seriously consider it up for debate whether or not it's a
> >> bug, when daily error messages are produced and emailed to the
> >> system admin?
> > 
> > That depends on whether you consider that to be the expected
> > behavior for the way it has been set up; the cause is already
> > known, wrong perms.
> 
> Well, it seems to be the Gentoo devs that set it up this way.
>
> You're the expert - you tell me why this is happening.

Your found information and the post installation messages tell this:

  "Traditionally mcelog was run as a cronjob, but this usage is
  deprecated now. The modern way to run it is to start it at
  boot up time and run it always as a daemon."

  "A sample cronjob is installed into /etc/cron.daily
  without executable bit (system service is the preferred method now)"

There is nothing extra for a non-maintainer to add to this.

> You haven't given me any explanation why this package is on a
> freshly-installed Gentoo system, you haven't told me in the Gentoo
> install docs that I need to configure this package, have you?

That is because you have installed it; and if you did install it, then
the useful post installation messages tell you this information.

To demonstrate that this is the case, app-admin/mcelog is ...

... not part of the current stage3 as revealed by its contents list;

    $ grep app-admin/mcelog stage3-amd64-20140410.tar.bz2.CONTENTS
    $

... not pulled in by another dependency as recorded in the database;

    $ grep --include='*DEPEND' -rl app-admin/mcelog /var/db/pkg/
    $

... not pulled in through profiles and therefore not by the @system set

    $ grep -r app-admin/mcelog /usr/portage/profiles/
    $

... and not listed as the dependency of any package in the Portage tree.

    $ grep --include='*.ebuild' --exclude='mcelog-*' -r app-admin/mcelog /usr/portage/
    $

-- 
With kind regards,

Tom Wijsman (TomWij)
Gentoo Developer

E-mail address  : TomWij@gentoo.org
GPG Public Key  : 6D34E57D
GPG Fingerprint : C165 AF18 AB4C 400B C3D2  ABF0 95B2 1FCD 6D34 E57D