BUG: KASAN: use-after-free in dec_rlimit_ucounts

[Qian Cai]

On Wed, Nov 24, 2021 at 04:49:19PM -0500, Qian Cai wrote:
> Hmm, I don't know if that or it is just this platfrom is lucky to trigger
> the race condition quickly, but I can't reproduce it on x86 so far. I am
> Cc'ing a few arm64 people to see if they have spot anything I might be
> missing. The original bug report is here:
> 
> https://lore.kernel.org/lkml/YZV7Z+yXbsx9p3JN@fixkernel.com/

Okay, I am finally able to reproduce this on x86_64 with the latest
mainline as well by setting CONFIG_USER_NS and KASAN on the top of
defconfig (I did not realize it did not select CONFIG_USER_NS in the first
place). Anyway, it still took less than 5-minute by running:

$ trinity -C 48