Re: [patch 6/7] process filtering for fault-injection capabilities

Don Mullis
2006-10-13T17:35:11Z

On Thu, 2006-10-12 at 16:43 +0900, Akinobu Mita wrote:
> This patch provides process filtering feature.
> The process filter allows failing only permitted processes
> by /proc/<pid>/make-it-fail

Akinobu: Toward the end of the previous round of review, we had
the following exchange:

On Tue, 2006-09-19 at 17:05 +0800, Akinobu Mita wrote:
On Mon, Sep 18, 2006 at 10:54:51PM -0700, Don Mullis wrote:
> > Add functionality to the process_filter variable: A negative argument
> > injects failures for only for pid==-process_filter, thereby permitting
> > per-process failures from boot time.
> >
>
> Is it better to add new filter for this purpose?
> Because someone may want to filter by tgid instead of pid.
>
> - positive value is for task->pid
> - nevative value is for task->tgid

Your idea sounds good to me.

So naturally I'm wondering why the functionality was dropped.
An application I had in mind was to identify which of the boot-time
calls to the slab allocator must not fail but are not yet marked
__GFP_NOFAIL (some experimentation showed that for pid 1 there are
lots of these).

Andrew: Would such an exercise would be worth the effort?