Re: [PATCH v3 11/19] unwind: Add deferred user space unwinding API

[Peter Zijlstra]

On Mon, Oct 28, 2024 at 02:47:38PM -0700, Josh Poimboeuf wrote:

> +/*
> + * The "context cookie" is a unique identifier which allows post-processing to
> + * correlate kernel trace(s) with user unwinds.  It has the CPU id the highest
> + * 16 bits and a per-CPU entry counter in the lower 48 bits.
> + */
> +static u64 ctx_to_cookie(u64 cpu, u64 ctx)
> +{
> +	BUILD_BUG_ON(NR_CPUS > 65535);
> +	return (ctx & ((1UL << 48) - 1)) | cpu;
> +}

Did you mean to: (cpu << 48) ?