Good catch. Curious how did you find it. KMEMCHECK or some such or just oom.
I've run glibc tests with 5.16 kernel and got many oom-killer messages and even kernel panic because lack of memory. These symptoms pointed to an issue. kmemleak didn't show anything. Didn't try kmemcheck. I prepared a small test and used git bisect to find to the "blame" commit.
Cc: stable@vger.kernel.org # 4.15.x
You meant 5.15.x
Yes, you right, that's my typo.
Added to for-curr.
Thanks!
Regards, Pavel