Re: 2.6.18-rc1-mm2: process `showconsole' used the removed sysctl system call

From: Michal Piotrowski
Date: Sat Jul 15 2006 - 20:49:28 EST


On 16/07/06, Eric W. Biederman <ebiederm@xxxxxxxxxxxx> wrote:
Michal Piotrowski <michal.k.k.piotrowski@xxxxxxxxx> writes:

> Hi Andrew,
>
> Andrew Morton wrote:
>> On Sat, 15 Jul 2006 16:40:36 +0200
>> Tilman Schmidt <tilman@xxxxxxx> wrote:
>>
>>> After installing a 2.6.18-rc1-mm2 kernel without sysctl syscall support
>>> on a standard SuSE 10.0 system, I find the following in my dmesg:
>>>
>>>> [ 36.955720] warning: process `showconsole' used the removed sysctl system
> call
>>>> [ 39.656410] warning: process `showconsole' used the removed sysctl system
> call
>>>> [ 43.304401] warning: process `showconsole' used the removed sysctl system
> call
>>>> [ 45.717220] warning: process `ls' used the removed sysctl system call
>>>> [ 45.789845] warning: process `touch' used the removed sysctl system call
>>> which at face value seems to contradict the statement in the help text
>>> for the CONFIG_SYSCTL_SYSCALL option that "Nothing has been using the
>>> binary sysctl interface for some time time now". (sic)
>>>
>>> Meanwhile, the second part of that sentence that "nothing should break"
>>> by disabling it seems to hold true anyway. The system runs fine, and
>>> activating CONFIG_SYSCTL_SYSCALL in the kernel doesn't seem to have any
>>> effect apart from changing the word "removed" to "obsolete" in the above
>>> messages.
>>
>> Thanks.
>>
>
> date and salsa also use sysctl.
>
> warning: process `date' used the removed sysctl system call
> warning: process `salsa' used the removed sysctl system call
>
>> Eric, that tends to make the whole idea inviable, doesn't it?
>
> How about _very_ long term to remove sysctl (i.e. January 2010)?

That may be reasonable. However please confirm that everything
that you have complaints from is using libpthreads.

ldd /bin/date
linux-gate.so.1 => (0xb7f22000)
librt.so.1 => /lib/librt.so.1 (0x4aab9000)
libc.so.6 => /lib/libc.so.6 (0x49ca3000)
libpthread.so.0 => /lib/libpthread.so.0 (0x49f38000)
/lib/ld-linux.so.2 (0x49c86000)

ldd /bin/ls
linux-gate.so.1 => (0xb7f23000)
librt.so.1 => /lib/librt.so.1 (0x4aab9000)
libselinux.so.1 => /lib/libselinux.so.1 (0x45a71000)
libc.so.6 => /lib/libc.so.6 (0x49ca3000)
libpthread.so.0 => /lib/libpthread.so.0 (0x49f38000)
/lib/ld-linux.so.2 (0x49c86000)
libdl.so.2 => /lib/libdl.so.2 (0x49dd8000)
libsepol.so.1 => /lib/libsepol.so.1 (0x41ad5000)

ldd /sbin/salsa
linux-gate.so.1 => (0xb7fd7000)
libasound.so.2 => /lib/libasound.so.2 (0x4100f000)
libc.so.6 => /lib/libc.so.6 (0x49ca3000)
libm.so.6 => /lib/libm.so.6 (0x49dde000)
libdl.so.2 => /lib/libdl.so.2 (0x49dd8000)
libpthread.so.0 => /lib/libpthread.so.0 (0x49f38000)
/lib/ld-linux.so.2 (0x49c86000)

ldd /bin/touch
linux-gate.so.1 => (0xb7fa2000)
librt.so.1 => /lib/librt.so.1 (0x4aab9000)
libc.so.6 => /lib/libc.so.6 (0x49ca3000)
libpthread.so.0 => /lib/libpthread.so.0 (0x49f38000)
/lib/ld-linux.so.2 (0x49c86000)

I can confirm this, but I don't have a "showconsole".


As there is one use of libpthreads that is using sysctl
in a very non-serious way.

With libptrheads modified to use uname and not sysctl I am not seeing that
message. I thought I had broken my test setup by forgetting to compile
glibc with --with-tls but I managed but I managed to get things working
again using LD_ASSUME_KERNEL=2.4.1

Still not the best data point but a very interesting one.

Eric


Regards,
Michal

--
Michal K. K. Piotrowski
LTG - Linux Testers Group
(http://www.stardust.webpages.pl/ltg/wiki/)
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