Re: [PATCH 2/2] kernel/entry: add kernel.syscall_user_dispatch sysctl

[Thomas Gleixner]

On Sat, Jun 27 2026 at 16:55, Gregory Price wrote:

Same comment vs. subject prefix.

> Add a matching sysctl to go with CONFIG_SYSCALL_USER_DISPATCH.
>
> kernel.syscall_user_dispatch (default 1) controls whether userspace
> may arm SUD (both via prctl and ptrace).

What's SUD again? This is a changelog and not twatter.

> +	/* Arming can be denied at runtime via sysctl, disarming is allowed */
> +	if (mode != PR_SYS_DISPATCH_OFF && !syscall_user_dispatch_allowed)
> +		return -EPERM;

That might be similar to other sysctls, but if an application had it
enabled prior to the sysctl=off toggle, then that application will
suddenly fail in operation if it requires to move the dispatch window.

Thanks,

        tglx