From: Tejun Heo <tj@kernel.org>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>,
Ingo Molnar <mingo@redhat.com>, Jiri Olsa <jolsa@redhat.com>,
linux-kernel@vger.kernel.org,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Subject: Re: [PATCH 1/2] trace_events_filter: use rcu_assign_pointer() when setting ftrace_event_call->filter
Date: Wed, 23 Nov 2011 09:33:13 -0800 [thread overview]
Message-ID: <20111123173313.GB29639@google.com> (raw)
In-Reply-To: <1322068000.20742.61.camel@frodo>
Hello, Steven.
On Wed, Nov 23, 2011 at 12:06:40PM -0500, Steven Rostedt wrote:
> > So, synchronized_sched() being called after isn't relevant. We want
> > smp_wmb() between data structure initialization and assignment of the
> > new pointer.
>
> Ah, you're saying that we need to guarantee that the allocated filter is
> seen before we update the call->filter to point to it. OK, fair enough,
> this does look like a bug fix.
>
> Is it big enough to be considered for stable?
It's unlikely to happen for x86 or arm and that probably is the
biggest reason there hasn't already been a bug report. It isn't very
urgent but at the same time the change is almost trivial, so marking
it for stable is a pretty safe bet. I lean toward marking it for
stable but the leaning isn't too strong. :)
Thanks.
--
tejun
next prev parent reply other threads:[~2011-11-23 17:33 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-11-23 1:46 [PATCH 1/2] trace_events_filter: use rcu_assign_pointer() when setting ftrace_event_call->filter Tejun Heo
2011-11-23 2:00 ` [PATCH 2/2] trace_event_filter: factorize filter creation Tejun Heo
2011-11-23 15:19 ` Steven Rostedt
2011-11-23 15:59 ` Tejun Heo
2011-11-28 20:49 ` Tejun Heo
2011-11-28 22:15 ` Steven Rostedt
2011-12-08 23:32 ` Tejun Heo
2011-12-09 0:15 ` Steven Rostedt
2011-12-09 0:46 ` Steven Rostedt
2011-12-09 18:55 ` Tejun Heo
2011-12-09 19:43 ` [PATCH 2/2 UPDATED] " Tejun Heo
2011-11-23 15:16 ` [PATCH 1/2] trace_events_filter: use rcu_assign_pointer() when setting ftrace_event_call->filter Steven Rostedt
2011-11-23 16:06 ` Tejun Heo
2011-11-23 16:12 ` Tejun Heo
2011-11-23 17:06 ` Steven Rostedt
2011-11-23 17:33 ` Tejun Heo [this message]
2011-11-28 16:49 ` Paul E. McKenney
2011-11-23 16:40 ` Eric Dumazet
2011-11-23 16:44 ` Tejun Heo
2011-11-23 16:49 ` [PATCH UPDATED " Tejun Heo
2011-12-05 17:34 ` [tip:perf/urgent] trace_events_filter: Use " tip-bot for Tejun Heo
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