Re: [GIT PULL] ucounts: Count rlimits in each user namespace

Linus Torvalds
2021-06-29T16:34:51Z

On Tue, Jun 29, 2021 at 8:52 AM Eric W. Biederman <ebiederm@xmission.com> wrote:
>
> Linus Torvalds <torvalds@linux-foundation.org> writes:
>
> > Why the "sigpending < LONG_MAX" test in that
> >
> > if (override_rlimit || (sigpending < LONG_MAX && sigpending <=
> > task_rlimit(t, RLIMIT_SIGPENDING))) {
> > thing?
>
> On second look that sigpending < LONG_MAX check is necessary. When
> inc_rlimit_ucounts detects a problem it returns LONG_MAX.

I saw that, but _without_ that test you'd be left with just that

sigpending <= task_rlimit(t, RLIMIT_SIGPENDING)

and if task_rlimit() is LONG_MAX, then that means "no limits", so it is all ok.

IOW, afaik even _if_ sigpending ends up being LONG_MAX, the
conditional does the right thing without that "sigpending < LONG_MAX"
test.

Linus