Re: clockevents_program_event WARN_ON preventing boot.

[Yinghai Lu]

On Fri, May 3, 2013 at 11:32 AM, Thomas Gleixner <tglx@xxxxxxxxxxxxx> wrote:
> Subject: tick: Use zalloc_cpumask_var for allocating offstack cpumasks
> From: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> Date: Fri, 03 May 2013 20:22:36 +0200
>
> commit b352bc1cbc (tick: Convert broadcast cpu bitmaps to
> cpumask_var_t) broke CONFIG_CPUMASK_OFFSTACK in a very subtle way.
>
> Instead of allocating the cpumasks with zalloc_cpumask_var it uses
> alloc_cpumask_var, so we can get random data there, which of course
> confuses the logic completely and causes random failures.
>
> Reported-by: Dave Jones <davej@xxxxxxxxxx>
> Reported-by: Yinghai Lu <yinghai@xxxxxxxxxx>
> Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> ---
>  kernel/time/tick-broadcast.c |   10 +++++-----
>  1 file changed, 5 insertions(+), 5 deletions(-)
>
> Index: linux-2.6/kernel/time/tick-broadcast.c
> ===================================================================
> --- linux-2.6.orig/kernel/time/tick-broadcast.c
> +++ linux-2.6/kernel/time/tick-broadcast.c
> @@ -785,11 +785,11 @@ bool tick_broadcast_oneshot_available(vo
>
>  void __init tick_broadcast_init(void)
>  {
> -       alloc_cpumask_var(&tick_broadcast_mask, GFP_NOWAIT);
> -       alloc_cpumask_var(&tmpmask, GFP_NOWAIT);
> +       zalloc_cpumask_var(&tick_broadcast_mask, GFP_NOWAIT);
> +       zalloc_cpumask_var(&tmpmask, GFP_NOWAIT);
>  #ifdef CONFIG_TICK_ONESHOT
> -       alloc_cpumask_var(&tick_broadcast_oneshot_mask, GFP_NOWAIT);
> -       alloc_cpumask_var(&tick_broadcast_pending_mask, GFP_NOWAIT);
> -       alloc_cpumask_var(&tick_broadcast_force_mask, GFP_NOWAIT);
> +       zalloc_cpumask_var(&tick_broadcast_oneshot_mask, GFP_NOWAIT);
> +       zalloc_cpumask_var(&tick_broadcast_pending_mask, GFP_NOWAIT);
> +       zalloc_cpumask_var(&tick_broadcast_force_mask, GFP_NOWAIT);
>  #endif
>  }

Yes, it works on Nehalem-EX 8 socket system now.

Tested-by: Yinghai Lu <yinghai@xxxxxxxxxx>
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