Re: [PATCH] powerpc/vdso: Fix vdso cpu truncation

On Thu, 16 Jul 2020 09:37:04 +1000, Anton Blanchard wrote:

The code in vdso_cpu_init that exposes the cpu and numa node to
userspace via SPRG_VDSO incorrctly masks the cpu to 12 bits. This means
that any kernel running on a box with more than 4096 threads (NR_CPUS
advertises a limit of of 8192 cpus) would expose userspace to two cpu
contexts running at the same time with the same cpu number.

Note: I'm not aware of any distro shipping a kernel with support for more
than 4096 threads today, nor of any system image that currently exceeds
4096 threads. Found via code browsing.

Applied to powerpc/next.

[1/1] powerpc/vdso: Fix vdso cpu truncation
      https://git.kernel.org/powerpc/c/a9f675f950a07d5c1dbcbb97aabac56f5ed085e3

cheers