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From: Peter Zijlstra <peterz@infradead.org>
To: Vince Weaver <vincent.weaver@maine.edu>
Cc: Stephane Eranian <eranian@google.com>,
	LKML <linux-kernel@vger.kernel.org>,
	Arnaldo Carvalho de Melo <acme@kernel.org>,
	Jiri Olsa <jolsa@redhat.com>, Ingo Molnar <mingo@redhat.com>,
	Paul Mackerras <paulus@samba.org>
Subject: Re: perf: fuzzer triggers NULL pointer derefreence in x86_schedule_events
Date: Wed, 20 May 2015 17:26:07 +0200	[thread overview]
Message-ID: <20150520152607.GK18673@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <20150520134922.GH18673@twins.programming.kicks-ass.net>

On Wed, May 20, 2015 at 03:49:22PM +0200, Peter Zijlstra wrote:
> ---
>  kernel/events/core.c |    5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/kernel/events/core.c b/kernel/events/core.c
> index 1a3bf48..a4f93fb 100644
> --- a/kernel/events/core.c
> +++ b/kernel/events/core.c
> @@ -7391,13 +7391,16 @@ static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
>  		ctx = perf_event_ctx_lock_nested(event->group_leader,
>  						 SINGLE_DEPTH_NESTING);
>  		BUG_ON(!ctx);
> +		raw_spin_lock_irq(&ctx->lock);
>  	}
>  
>  	event->pmu = pmu;
>  	ret = pmu->event_init(event);
>  
> -	if (ctx)
> +	if (ctx) {
> +		raw_spin_unlock_irq(&ctx->lock);
>  		perf_event_ctx_unlock(event->group_leader, ctx);
> +	}
>  
>  	if (ret)
>  		module_put(pmu->module);

Except of course that ->event_init() likes to do an allocation :/

Needs to be fixed differently.

  reply	other threads:[~2015-05-20 15:26 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-04-30 19:08 perf: fuzzer triggers NULL pointer derefreence in x86_schedule_events Vince Weaver
2015-05-01 12:59 ` Peter Zijlstra
2015-05-04 19:32   ` Stephane Eranian
2015-05-07 12:43     ` Peter Zijlstra
2015-05-08  4:25       ` Vince Weaver
2015-05-18 17:40       ` Vince Weaver
2015-05-20 13:03         ` Peter Zijlstra
2015-05-20 13:15           ` Peter Zijlstra
2015-05-20 13:49           ` Peter Zijlstra
2015-05-20 15:26             ` Peter Zijlstra [this message]
2015-05-20 16:09               ` Peter Zijlstra
2015-05-24 19:14 ` Jiri Olsa

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