Re: [PATCH v2] x86: correct socket_cpumask allocation

[Andrew Cooper <andrew.cooper3@citrix.com>]

On 09/07/15 09:26, Chao Peng wrote:
> For booting cpu, the socket number is not needed to be 0 so
> it needs to be computed by cpu number.
>
> For secondary cpu, phys_proc_id is not valid in CPU_PREPARE
> notifier(cpu_smpboot_alloc), so cpu_to_socket(cpu) can't be used.
> Instead, pre-allocate secondary_cpu_mask in cpu_smpboot_alloc()
> and later consume it in smp_store_cpu_info().
>
> This patch also change socket_cpumask type from 'cpumask_var_t *'
> to 'cpumask_t **' so that smaller NR_CPUS works.
>
> Reported-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
> Signed-off-by: Chao Peng <chao.p.peng@linux.intel.com>

I have thrown this patch into my XenServer upstream testing branch, to
get a wide coverage of servers.

(So far, on a random sample of 24 servers from our testing pool, not a
single one has successfully booted with the original bug present.)

~Andrew