Re: [PATCH 05/11] smp: Enable preemption early in smp_call_function_many_cond

[Peter Zijlstra]

On Tue, Feb 03, 2026 at 07:23:55PM +0800, Chuyi Zhou wrote:

> +	/*
> +	 * Prevent the current CPU from going offline.
> +	 * Being migrated to another CPU and calling csd_lock_wait() may cause
> +	 * UAF due to smpcfd_dead_cpu() during the current CPU offline process.
> +	 */
> +	migrate_disable();

This is horrible crap. migrate_disable() is *NOT* supposed to be used to
serialize cpu hotplug.