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sysctl: make CONFIG_SYSCTL_SYSCALL default to n

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When I tried to send a patch to remove it, Andi told me we still need to
keep compabitlies for old libc, so we can't remove this completely.  Then
just make it default to n and remove the doc from
feature-removal-schedule.txt.

Signed-off-by: WANG Cong <amwang@redhat.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
WANG Cong 2011-11-02 13:39:25 -07:00 committed by Linus Torvalds
parent f1ecf06854
commit c736de60ae
2 changed files with 2 additions and 37 deletions
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35
Documentation/feature-removal-schedule.txt
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@ -133,41 +133,6 @@ Who: Pavel Machek <pavel@ucw.cz>
---------------------------
What: sys_sysctl
When: September 2010
Option: CONFIG_SYSCTL_SYSCALL
Why: The same information is available in a more convenient from
/proc/sys, and none of the sysctl variables appear to be
important performance wise.
Binary sysctls are a long standing source of subtle kernel
bugs and security issues.
When I looked several months ago all I could find after
searching several distributions were 5 user space programs and
glibc (which falls back to /proc/sys) using this syscall.
The man page for sysctl(2) documents it as unusable for user
space programs.
sysctl(2) is not generally ABI compatible to a 32bit user
space application on a 64bit and a 32bit kernel.
For the last several months the policy has been no new binary
sysctls and no one has put forward an argument to use them.
Binary sysctls issues seem to keep happening appearing so
properly deprecating them (with a warning to user space) and a
2 year grace warning period will mean eventually we can kill
them and end the pain.
In the mean time individual binary sysctls can be dealt with
in a piecewise fashion.
Who: Eric Biederman <ebiederm@xmission.com>
---------------------------
What: /proc/<pid>/oom_adj
When: August 2012
Why: /proc/<pid>/oom_adj allows userspace to influence the oom killer's

4
init/Kconfig
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@ -947,7 +947,7 @@ config UID16
config SYSCTL_SYSCALL
bool "Sysctl syscall support" if EXPERT
depends on PROC_SYSCTL
default y
default n
select SYSCTL
---help---
sys_sysctl uses binary paths that have been found challenging
@ -959,7 +959,7 @@ config SYSCTL_SYSCALL
trying to save some space it is probably safe to disable this,
making your kernel marginally smaller.
If unsure say Y here.
If unsure say N here.
config KALLSYMS
bool "Load all symbols for debugging/ksymoops" if EXPERT