Re: Patch 1/6 introduce sysctl

[Benoit Boissinot <bboissin@gmail.com>]

On Thu, 27 Jan 2005 10:12:01 +0000, Arjan van de Ven
<arjan@infradead.org> wrote:
> 
> This first patch of the series introduces a sysctl (default off) that
> enables/disables the randomisation feature globally. Since randomisation may
> make it harder to debug really tricky situations (reproducability goes
> down), the sysadmin needs a way to disable it globally.
> 
> Signed-off-by: Arjan van de Ven <arjan@infradead.org>
> 
> diff -purN linux-2.6.11-rc2-bk4/include/linux/kernel.h linux-step-1/include/linux/kernel.h
> --- linux-2.6.11-rc2-bk4/include/linux/kernel.h 2005-01-26 18:24:39.000000000 +0100
> +++ linux-step-1/include/linux/kernel.h 2005-01-26 19:04:58.016540168 +0100
> @@ -278,6 +278,9 @@ struct sysinfo {
>  extern void BUILD_BUG(void);
>  #define BUILD_BUG_ON(condition) do { if (condition) BUILD_BUG(); } while(0)
> 
> +
> +extern int randomize_va_space;
> +
>  /* Trap pasters of __FUNCTION__ at compile-time */
>  #if __GNUC__ > 2 || __GNUC_MINOR__ >= 95
>  #define __FUNCTION__ (__func__)
> [snip]
>
> diff -purN linux-2.6.11-rc2-bk4/kernel/sysctl.c linux-step-1/kernel/sysctl.c
> --- linux-2.6.11-rc2-bk4/kernel/sysctl.c        2005-01-26 18:24:39.000000000 +0100
> +++ linux-step-1/kernel/sysctl.c        2005-01-26 19:03:44.000000000 +0100
> @@ -122,6 +122,8 @@ extern int sysctl_hz_timer;
>  extern int acct_parm[];
>  #endif
> 
> +int randomize_va_space = 0;
> +
>  static int parse_table(int __user *, int, void __user *, size_t __user *, void __user *, size_t,
>                        ctl_table *, void **);
>  static int proc_doutsstring(ctl_table *table, int write, struct file *filp,
>
> [snip]

This breaks the compilation with allnoconfig (since CONFIG_SYSCTL is
not defined):

arch/i386/kernel/built-in.o(.text+0xf92): In function `arch_align_stack':
: undefined reference to `randomize_va_space'

maybe randomize_va_space should be defined as extern in sysctl.c and
put elsewhere.

regards,

Benoit