Re: [RFC PATCH 0/6] RLIMIT_NPROC in ucounts fixups

[Michal Koutný]

On Sat, Feb 12, 2022 at 03:32:30PM +0000, Etienne Dechamps <etienne@xxxxxxxxxxxx> wrote:
> I'm not sure I understand everything that's going on in this thread but it
> does seem very relevant. You guys might want to double-check the behavior in
> the particular scenario described there. I'm mostly sending this to make
> sure everything is cross-linked.

Thanks for the report with strace.

AFAICT, it's caused by setresuid() after unshare(), i.e. all root's
tasks are (wrongly) compared against the lowered RLIMIT_NPROC.

This is tackled by my RFC patch 2/6 [1] or Eric's variant but 3/8
(equivalent fix for this case but I haven't run that build).

Michal

[1] I could run your test (LimitNPROC=1 actually) against kernel with my
patches and the service starts.