Re: [PATCH][2.6] WARN_ON_STACK_VAR aka fighting variable lifetime bugs

[Zwane Mwaikambo <zwane@linuxpower.ca>]

On Mon, 11 Aug 2003, David Mosberger wrote:

> >>>>> On Sat, 9 Aug 2003 15:29:41 -0400 (EDT), Zwane Mwaikambo <zwane@arm.linux.org.uk> said:
> 
>   Zwane> --- linux-2.6.0-test2-irq/include/asm-ia64/bug.h	30 Jul 2003 00:06:30 -0000	1.1.1.1
>   Zwane> +++ linux-2.6.0-test2-irq/include/asm-ia64/bug.h	9 Aug 2003 19:14:09 -0000
>   Zwane> +#define WARN_ON_STACK_VAR(ptr) do { \
>   Zwane> +	unsigned long __ti = (unsigned long)current_thread_info(); \
>   Zwane> +	WARN_ON((__ti & (unsigned long)(ptr)) == __ti); \
>   Zwane> +} while (0)
> 
> Note that on ia64 we don't use bit-masking to calculate the
> task-pointer.  Instead, thread-info follows the task structure.  This
> is done such that the task-structure, thread-info, and kernel stack
> can be mapped by a single (pinned) TLB entry.
> 
> The correct check for a variable being on the stack of the current
> task would be something like this:
> 
> 	((unsigned long)(ptr) - (unsigned long) current) < IA64_STK_OFFSET
> 
> (IA64_STK_OFFSET is declared by <asm/ptrace.h>).

Ah thanks =) i've modified my patch accordingly.

	Zwane