Re: [PATCH v2 1/2] procfs: make /proc/*/{stack,syscall,personality} 0400

[Oleg Nesterov <oleg@redhat.com>]

On 03/28, Andrew Morton wrote:
>
> Now for a six-year-late code review:
>
> - How the heck can target==current in task_current_syscall()?
>
> - Less talk, more action:
>
> From: Andrew Morton <akpm@linux-foundation.org>
> Subject: lib/syscall.c: unexport task_current_syscall()
>
> It is only used by procfs and procfs cannot be a module.
>
> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
> ---
>
>  lib/syscall.c |    1 -
>  1 file changed, 1 deletion(-)
>
> diff -puN lib/syscall.c~a lib/syscall.c
> --- a/lib/syscall.c~a
> +++ a/lib/syscall.c
> @@ -72,4 +72,3 @@ int task_current_syscall(struct task_str
>
>  	return 0;
>  }
> -EXPORT_SYMBOL_GPL(task_current_syscall);

Well, I guess it was added for external tracing modules like systemtap.
And in this case target==current is very likely. And for utrace modules,
but it is dead.

I do not see any usage of task_current_syscall() in
git://sourceware.org/git/systemtap.git, so this change should not upset
systemtap at least.

And if we unexport task_current_syscall(), perhaps we should actually
lib/syscall.c. proc_pid_syscall() can use syscall_get_*() instead.
Or at least we can simplify it, I don't think /proc/ actually needs
wait_task_inactive().

Oleg.