oom-killer is crazy? (Was: [PATCH 0/3] uprobes fixes for 3.5)

[Oleg Nesterov <oleg@redhat.com>]

On 06/07, Oleg Nesterov wrote:
>
> This doesn't depend on other uprobes patches I sent, and I think
> this is 3.5 material.

And during the testing I found another thing which should be fixed
in 3.5 imho. I noticed that oom-killer goes crazy. In the simplest
case, when there is the single and "obvious" memory hog it kills
sshd daemon.

Hmm. oom_badness() does

	if (has_capability_noaudit(p, CAP_SYS_ADMIN))
		points -= 30 * totalpages / 1000;

very nice, but what if this underflows? points is unsigned long.
points += p->signal->oom_score_adj... looks suspicious too.

Looks like we should remove "unsigned" from oom_badness() and
its callers? Probably not, it does "return points ? points : 1".

Confused.

Oleg.