Re: [PATCH] x86/cpu: identify uninitialized CPU data using BAD_APICID

[Teddy Astie <teddy.astie@xxxxxxxxxx>]

Le 30/04/2026 à 13:47, Roger Pau Monne a écrit :
> Uninitialized cpu_data[] entries have the apicid field set to BAD_APICID,
> not boot_cpu_data.apicid.  Fix the check in cpu_smpboot_free() to use the
> correct condition.
> 
> Fixes: 7126b7f806d5 ("x86/CPU: re-work populating of cpu_data[]")
> Signed-off-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
> ---
>   xen/arch/x86/smpboot.c | 3 +--
>   1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/xen/arch/x86/smpboot.c b/xen/arch/x86/smpboot.c
> index 491cbbba33ae..ff05955bae40 100644
> --- a/xen/arch/x86/smpboot.c
> +++ b/xen/arch/x86/smpboot.c
> @@ -961,8 +961,7 @@ static void cpu_smpboot_free(unsigned int cpu, bool 
> remove)
>        * In that case the socket number cannot be relied upon, but the 
> respective
>        * socket_cpumask[] slot also wouldn't have been set.
>        */
> -    if ( c[cpu].apicid != boot_cpu_data.apicid &&
> -         cpumask_empty(socket_cpumask[socket]) )
> +    if ( c[cpu].apicid != BAD_APICID && 
> cpumask_empty(socket_cpumask[socket]) )
>       {
>           xfree(socket_cpumask[socket]);
>           socket_cpumask[socket] = NULL;

Reviewed-by: Teddy Astie <teddy.astie@xxxxxxxxxx>


--
Teddy Astie | Vates XCP-ng Developer

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