From: Peter Zijlstra <peterz@infradead.org>
To: Oleg Nesterov <oleg@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>, Paul Mackerras <paulus@samba.org>,
Ingo Molnar <mingo@elte.hu>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH,RFC] perf: panic due to inclied cpu context task_ctx value
Date: Mon, 28 Mar 2011 17:49:28 +0200 [thread overview]
Message-ID: <1301327368.4859.28.camel@twins> (raw)
In-Reply-To: <1301324275.4859.25.camel@twins>
On Mon, 2011-03-28 at 16:57 +0200, Peter Zijlstra wrote:
> >
> > Wait... Yes, we have to clear ctx->is_active, otherwise we break, say,
> > perf_install_in_context().
> >
> > But if we clear ->is_active we break perf_event_enable(). Suppose we
> > are doing ioctl(PERF_EVENT_IOC_DISABLE) + ioctl(PERF_EVENT_IOC_ENABLE).
> > PERF_EVENT_IOC_DISABLE can sched_out the last event, but _IOC_ENABLE
> > treats ctx->is_active == F as "it is not running".
>
> Right, same for the tick, if say we can only schedule 1 event at a time
> and we close the 1 event that is active, the tick will not rotate a new
> event in.
Another fun race, suppose we do properly remove task_ctx and is_active,
but then the task gets scheduled back in before free_event() gets around
to disabling the jump_label..
next prev parent reply other threads:[~2011-03-28 15:49 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-03-24 16:44 [PATCH,RFC] perf: panic due to inclied cpu context task_ctx value Jiri Olsa
2011-03-25 19:10 ` Oleg Nesterov
2011-03-26 15:37 ` Peter Zijlstra
2011-03-26 16:13 ` Oleg Nesterov
2011-03-26 16:38 ` Peter Zijlstra
2011-03-26 17:09 ` Oleg Nesterov
2011-03-26 17:35 ` Oleg Nesterov
2011-03-26 18:29 ` Peter Zijlstra
2011-03-26 18:49 ` Oleg Nesterov
2011-03-28 13:30 ` Oleg Nesterov
2011-03-28 14:57 ` Peter Zijlstra
2011-03-28 15:00 ` Peter Zijlstra
2011-03-28 15:15 ` Oleg Nesterov
2011-03-28 16:27 ` Peter Zijlstra
2011-03-28 15:39 ` Oleg Nesterov
2011-03-28 15:49 ` Peter Zijlstra [this message]
2011-03-28 16:56 ` Oleg Nesterov
2011-03-29 8:32 ` Peter Zijlstra
2011-03-29 10:49 ` Peter Zijlstra
2011-03-29 16:28 ` Oleg Nesterov
2011-03-29 19:01 ` Peter Zijlstra
2011-03-30 13:09 ` Jiri Olsa
2011-03-30 14:51 ` Peter Zijlstra
2011-03-30 16:37 ` Oleg Nesterov
2011-03-30 18:30 ` Paul E. McKenney
2011-03-30 19:53 ` Oleg Nesterov
2011-03-30 21:26 ` Peter Zijlstra
2011-03-30 21:35 ` Oleg Nesterov
2011-03-31 10:32 ` Jiri Olsa
2011-03-31 12:41 ` [tip:perf/urgent] perf: Fix task context scheduling tip-bot for Peter Zijlstra
2011-03-31 13:28 ` [PATCH,RFC] perf: panic due to inclied cpu context task_ctx value Oleg Nesterov
2011-03-31 13:51 ` Peter Zijlstra
2011-03-31 14:10 ` Oleg Nesterov
2011-04-04 16:20 ` Oleg Nesterov
2011-03-30 15:32 ` Oleg Nesterov
2011-03-30 15:40 ` Peter Zijlstra
2011-03-30 15:52 ` Oleg Nesterov
2011-03-30 15:57 ` Peter Zijlstra
2011-03-30 16:11 ` Peter Zijlstra
2011-03-30 17:13 ` Oleg Nesterov
2011-03-26 17:09 ` Peter Zijlstra
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