Re: [PATCH v2] selftests/pid_namespace: compute pid_max test limits dynamically

[Christian Brauner <brauner@kernel.org>]

On Wed, 22 Apr 2026 20:11:51 +0000, Bjoern Doebel wrote:
> The pid_max kselftest hardcodes pid_max values of 400 and 500, but the
> kernel enforces a minimum of PIDS_PER_CPU_MIN * num_possible_cpus().
> On machines with many possible CPUs (e.g. nr_cpu_ids=128 yields a
> minimum of 1024), writing 400 or 500 to /proc/sys/kernel/pid_max
> returns EINVAL and all three tests fail.
> 
> Compute these limits the same way as the kernel does and set outer_limit
> and inner_limit dynamically based on the result. Original test semantics
> are preserved (outer < inner, nested namespace capped by parent).
> 
> [...]

Applied to the kernel-7.2.misc branch of the vfs/vfs.git tree.
Patches in the kernel-7.2.misc branch should appear in linux-next soon.

Please report any outstanding bugs that were missed during review in a
new review to the original patch series allowing us to drop it.

It's encouraged to provide Acked-bys and Reviewed-bys even though the
patch has now been applied. If possible patch trailers will be updated.

Note that commit hashes shown below are subject to change due to rebase,
trailer updates or similar. If in doubt, please check the listed branch.

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs.git
branch: kernel-7.2.misc

[1/1] selftests/pid_namespace: compute pid_max test limits dynamically
      https://git.kernel.org/vfs/vfs/c/d324c5416a63