2006-10-04 20:35:05

by Jesper Juhl

[permalink] [raw]
Subject: removed sysctl system call - documentation and timeline

Hi,

With recent kernels I'm getting a lot of warnings about programs using
the removed sysctl syscal.

Examples (after 5 min of uptime here) :
root@dragon:/home/juhl# dmesg | grep "used the removed sysctl system
call" | sort | uniq
warning: process `dd' used the removed sysctl system call
warning: process `ls' used the removed sysctl system call
warning: process `touch' used the removed sysctl system call

and more can be found...


I'm not, as such, opposed to removing sysctl (and yes, I know what it
is and what it does). What I am a little opposed to is that it is
being removed on such short notice (unless I missed the memo) and that
it is hidden inside EMBEDDED.

I would like to propose that, at least for 2.6.19, it be default on
(as it is now), not hide it in EMBEDDED where people usually don't go,
some huge deprecation warnings be added, and that it then gets the
usual 6-12months before being removed (did it already get that and I'm
just slow?)... ohhh, and correct the help text; it currently says
"...Nothing has been using the binary sysctl interface for some time
now so nothing should break if you disable sysctl syscall support" -
that's obviously false as demonstrated by the above extract from my
dmesg...

--
Jesper Juhl <[email protected]>
Don't top-post http://www.catb.org/~esr/jargon/html/T/top-post.html
Plain text mails only, please http://www.expita.com/nomime.html


2006-10-04 20:45:19

by Jeremy Fitzhardinge

[permalink] [raw]
Subject: Re: removed sysctl system call - documentation and timeline

Jesper Juhl wrote:
> ohhh, and correct the help text; it currently says
> "...Nothing has been using the binary sysctl interface for some time
> now so nothing should break if you disable sysctl syscall support" -
> that's obviously false as demonstrated by the above extract from my
> dmesg...
>

It's half true. It's true that things try to use it, but they'll
happily fall back to something else (/proc?) if it doesn't work. I used
to get those messages, but it appears that recent glibcs don't use it at
all.

J

2006-10-04 20:50:28

by Alessandro Suardi

[permalink] [raw]
Subject: Re: removed sysctl system call - documentation and timeline

On 10/4/06, Jesper Juhl <[email protected]> wrote:
> Hi,
>
> With recent kernels I'm getting a lot of warnings about programs using
> the removed sysctl syscal.
>
> Examples (after 5 min of uptime here) :
> root@dragon:/home/juhl# dmesg | grep "used the removed sysctl system
> call" | sort | uniq
> warning: process `dd' used the removed sysctl system call
> warning: process `ls' used the removed sysctl system call
> warning: process `touch' used the removed sysctl system call
>
> and more can be found...
>
>
> I'm not, as such, opposed to removing sysctl (and yes, I know what it
> is and what it does). What I am a little opposed to is that it is
> being removed on such short notice (unless I missed the memo) and that
> it is hidden inside EMBEDDED.
>
> I would like to propose that, at least for 2.6.19, it be default on
> (as it is now), not hide it in EMBEDDED where people usually don't go,
> some huge deprecation warnings be added, and that it then gets the
> usual 6-12months before being removed (did it already get that and I'm
> just slow?)... ohhh, and correct the help text; it currently says
> "...Nothing has been using the binary sysctl interface for some time
> now so nothing should break if you disable sysctl syscall support" -
> that's obviously false as demonstrated by the above extract from my
> dmesg...

Another data point then... this is FC5-uptodate:

[asuardi@sandman incoming]$ dmesg | grep -i sysctl
warning: process `date' used the removed sysctl system call
warning: process `touch' used the removed sysctl system call
warning: process `salsa' used the removed sysctl system call

--alessandro

"Well a man has two reasons for things that he does
the first one is pride and the second one is love
all understandings must come by this way"

(Husker Du, 'She Floated Away')

2006-10-04 21:14:31

by Adrian Bunk

[permalink] [raw]
Subject: Re: removed sysctl system call - documentation and timeline

On Wed, Oct 04, 2006 at 10:35:01PM +0200, Jesper Juhl wrote:
> Hi,
>
> With recent kernels I'm getting a lot of warnings about programs using
> the removed sysctl syscal.
>
> Examples (after 5 min of uptime here) :
> root@dragon:/home/juhl# dmesg | grep "used the removed sysctl system
> call" | sort | uniq
> warning: process `dd' used the removed sysctl system call
> warning: process `ls' used the removed sysctl system call
> warning: process `touch' used the removed sysctl system call
>
> and more can be found...
>
>
> I'm not, as such, opposed to removing sysctl (and yes, I know what it
> is and what it does). What I am a little opposed to is that it is
> being removed on such short notice (unless I missed the memo) and that
> it is hidden inside EMBEDDED.
>
> I would like to propose that, at least for 2.6.19, it be default on
> (as it is now), not hide it in EMBEDDED where people usually don't go,

This abuse of EMBEDDED is nonsense.

SYSCTL_SYSCALL should be moved above EMBEDDED (for not breaking the
menu), and the "if EMBEDDED" removed.

> some huge deprecation warnings be added, and that it then gets the
> usual 6-12months before being removed (did it already get that and I'm
> just slow?)... ohhh, and correct the help text; it currently says

It seems you are slow...

It's entry in Documentation/feature-removal-schedule.txt fulfills the
6 months.

> "...Nothing has been using the binary sysctl interface for some time
> now so nothing should break if you disable sysctl syscall support" -
> that's obviously false as demonstrated by the above extract from my
> dmesg...

What did actually break (a dmesg message is not a breakage)?

cu
Adrian

--

"Is there not promise of rain?" Ling Tan asked suddenly out
of the darkness. There had been need of rain for many days.
"Only a promise," Lao Er said.
Pearl S. Buck - Dragon Seed

2006-10-04 21:33:20

by Alan

[permalink] [raw]
Subject: Re: removed sysctl system call - documentation and timeline

Ar Mer, 2006-10-04 am 22:35 +0200, ysgrifennodd Jesper Juhl:
> I'm not, as such, opposed to removing sysctl (and yes, I know what it
> is and what it does). What I am a little opposed to is that it is
> being removed on such short notice (unless I missed the memo) and that
> it is hidden inside EMBEDDED.

It was deprecated but 6 months for a syscall is way too short and it
should have been (and still should - send Linus patches and I'm sure
lots of people will ack them) under EMBEDDED

Alan

2006-10-04 22:41:52

by Andi Kleen

[permalink] [raw]
Subject: Re: removed sysctl system call - documentation and timeline

"Jesper Juhl" <[email protected]> writes:

> Hi,
>
> With recent kernels I'm getting a lot of warnings about programs using
> the removed sysctl syscal.
>
> Examples (after 5 min of uptime here) :
> root@dragon:/home/juhl# dmesg | grep "used the removed sysctl system
> call" | sort | uniq
> warning: process `dd' used the removed sysctl system call
> warning: process `ls' used the removed sysctl system call
> warning: process `touch' used the removed sysctl system call
>
> and more can be found...

They all only use a single sysctl (kernel/version). IMHO that
one should be just emulated and the rest -ENOSYSed. There used
to be a slightly buggy patch for that in tree.

I think that would give all the advantages (dropping of the
numerical name space) with 99+% backwards compatibility

-Andi