From: Oleg Nesterov <oleg@redhat.com>
To: Markus Metzger <markus.t.metzger@intel.com>
Cc: linux-kernel@vger.kernel.org, mingo@elte.hu, tglx@linutronix.de,
hpa@zytor.com, markus.t.metzger@gmail.com, roland@redhat.com,
eranian@googlemail.com, juan.villacis@intel.com,
ak@linux.jf.intel.com
Subject: Re: [patch 3/14] x86, ptrace, bts: stop bts tracing early in do_exit
Date: Fri, 27 Mar 2009 15:34:35 +0100 [thread overview]
Message-ID: <20090327143435.GD14504@redhat.com> (raw)
In-Reply-To: <20090327095525.A11052@sedona.ch.intel.com>
On 03/27, Markus Metzger wrote:
>
> +static void ptrace_bts_exit(void)
> +{
> + if (unlikely(!list_empty(¤t->ptraced)))
> + ptrace_bts_exit_tracer();
> +
> + if (unlikely(current->bts))
> + ptrace_bts_exit_tracee();
> +}
Could you explain why do we need ptrace_bts_exit_tracee() ?
If current is traced, the tracer should do ptrace_bts_release()
eventually, no?
And if we really need to do ptrace_bts_exit_tracee(), then
"if (unlikely(current->bts))" check is racy. The tracer
can do PTRACE_BTS_CONFIG right after the check.
Oleg.
next prev parent reply other threads:[~2009-03-27 14:38 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-03-27 8:55 [patch 3/14] x86, ptrace, bts: stop bts tracing early in do_exit Markus Metzger
2009-03-27 14:34 ` Oleg Nesterov [this message]
2009-03-27 15:34 ` Metzger, Markus T
2009-03-27 17:24 ` Oleg Nesterov
2009-03-27 19:25 ` Markus Metzger
2009-03-28 11:31 ` Markus Metzger
2009-03-30 1:22 ` Oleg Nesterov
2009-03-30 6:55 ` Metzger, Markus T
2009-03-30 10:44 ` Andi Kleen
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