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Message-ID: <4F7E0A6A.40204@amd.com>
Date: Thu, 5 Apr 2012 17:11:06 -0400
From: Boris Ostrovsky <boris.ostrovsky@amd.com>
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To: Jiri Slaby <jslaby@suse.cz>, Len Brown <len.brown@intel.com>
CC: LKML <linux-kernel@vger.kernel.org>,
        the arch/x86 maintainers <x86@kernel.org>,
        Jiri Slaby <jirislaby@gmail.com>, Toshi Kani <toshi.kani@hp.com>
Subject: Re: BUG at cpuidle_play_dead
References: <4F7E0884.5090602@suse.cz>
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On 04/05/12 17:03, Jiri Slaby wrote:
> Hi,
>
> I'm hitting this BUG as the last thing during shutdown:
> BUG: unable to handle kernel NULL pointer dereference at 00000000000002d8
> IP: [<ffffffff814ab60d>] cpuidle_play_dead+0x1d/0xb0
>
>
> It's because drv is NULL. The problem is gone if I do this:
> --- a/drivers/cpuidle/cpuidle.c
> +++ b/drivers/cpuidle/cpuidle.c
> @@ -83,6 +83,11 @@ int cpuidle_play_dead(void)
>          int i, dead_state = -1;
>          int power_usage = -1;
>
> +       if (!drv) {
> +               printk("DRIVER IS NULL\n");
> +               return -ENODEV;
> +       }
> +
>          /* Find lowest-power state that supports long-term idle */
>          for (i = CPUIDLE_DRIVER_STATE_START; i<  drv->state_count; i++) {
>                  struct cpuidle_state *s =&drv->states[i];
>
> thanks,


This was already fixed in https://lkml.org/lkml/2012/3/31/249.

Len, please apply that patch.

Thanks.
-boris