Re: [PATCH] perf/x86/intel/pt: Fix lockdep interaction

[Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>]

Oops, didn't mean to send this here since it is not graphics related.

But it does happen on SKL so maybe it will be useful for someone.

Tvrtko

On 06/02/2015 12:37 PM, Tvrtko Ursulin wrote:
> From: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
>
> Since this drivers creates attributes on the heap, lockdep
> gets upset and disabled itself.
>
> Fix by setting ignore_lockdep flags for problematic attributes.
>
> Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
> Cc: Ingo Molnar <mingo@kernel.org>
> Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
> Cc: x86@kernel.org
> Cc: Michał Winiarski <michal.winiarski@intel.com>
> ---
> Not saying this is a right fix but lets say I am trying to force the issue. :)
> ---
>   arch/x86/kernel/cpu/perf_event_intel_pt.c | 7 ++++---
>   1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/arch/x86/kernel/cpu/perf_event_intel_pt.c b/arch/x86/kernel/cpu/perf_event_intel_pt.c
> index ffe666c..1cff27b 100644
> --- a/arch/x86/kernel/cpu/perf_event_intel_pt.c
> +++ b/arch/x86/kernel/cpu/perf_event_intel_pt.c
> @@ -153,9 +153,10 @@ static int __init pt_pmu_hw_init(void)
>
>   		sysfs_attr_init(&de_attrs->attr.attr);
>
> -		de_attr->attr.attr.mode		= S_IRUGO;
> -		de_attr->attr.show		= pt_cap_show;
> -		de_attr->var			= (void *)i;
> +		de_attr->attr.attr.mode		  = S_IRUGO;
> +		de_attr->attr.show		  = pt_cap_show;
> +		de_attr->attr.attr.ignore_lockdep = 1;
> +		de_attr->var			  = (void *)i;
>
>   		attrs[i] = &de_attr->attr.attr;
>   	}
>
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