From: Li Zefan <lizf@cn.fujitsu.com>
To: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
Avi Kivity <avi@redhat.com>, Ingo Molnar <mingo@elte.hu>,
Steven Rostedt <rostedt@goodmis.org>,
kvm-devel <kvm@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: ftrace/perf_event leak
Date: Thu, 02 Sep 2010 09:20:38 +0800 [thread overview]
Message-ID: <4C7EFBE6.3040408@cn.fujitsu.com> (raw)
In-Reply-To: <20100901121518.GA5378@nowhere>
>> Subject: perf, trace: Fix module leak
>> From: Li Zefan <lizf@cn.fujitsu.com>
>> Date: Wed Sep 01 12:58:43 CEST 2010
>>
>> Commit 1c024eca (perf, trace: Optimize tracepoints by using
>> per-tracepoint-per-cpu hlist to track events) caused a module refcount
>> leak.
>>
>> Tested-by: Avi Kivity <avi@redhat.com>
>> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
>> LKML-Reference: <4C7E1F12.8030304@cn.fujitsu.com>
>> ---
>> kernel/trace/trace_event_perf.c | 3 +++
>> 1 file changed, 3 insertions(+)
>>
>> Index: linux-2.6/kernel/trace/trace_event_perf.c
>> ===================================================================
>> --- linux-2.6.orig/kernel/trace/trace_event_perf.c
>> +++ linux-2.6/kernel/trace/trace_event_perf.c
>> @@ -91,6 +91,8 @@ int perf_trace_init(struct perf_event *p
>> tp_event->class && tp_event->class->reg &&
>> try_module_get(tp_event->mod)) {
>> ret = perf_trace_event_init(tp_event, p_event);
>> + if (ret)
>> + module_put(tp_event->mod);
>> break;
>> }
>> }
>> @@ -147,6 +149,7 @@ void perf_trace_destroy(struct perf_even
>> }
>> }
>> out:
>> + module_put(tp_event->mod);
>> mutex_unlock(&event_mutex);
>> }
>>
>>
>
> Thanks for fixing this.
>
> However, can we split this in two patches to ease the backport?
>
> The lack of a module_put() after perf_trace_init() failure is there for a while
> (the backport needs to start in 2.6.32).
The failure should be a rare case, I don't think this has to be backported?
>
> But the lack of a module_put in the destroy path needs a .35 backport only.
>
next prev parent reply other threads:[~2010-09-02 1:15 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-09-01 8:42 ftrace/perf_event leak Avi Kivity
2010-09-01 9:04 ` Peter Zijlstra
2010-09-01 9:26 ` Avi Kivity
2010-09-01 9:35 ` Peter Zijlstra
2010-09-01 9:38 ` Li Zefan
2010-09-01 9:41 ` Peter Zijlstra
2010-09-01 10:38 ` Avi Kivity
2010-09-01 11:02 ` Peter Zijlstra
2010-09-01 11:07 ` Ingo Molnar
2010-09-01 12:15 ` Frederic Weisbecker
2010-09-01 13:59 ` Steven Rostedt
2010-09-01 17:32 ` Ingo Molnar
2010-09-02 1:20 ` Li Zefan [this message]
2010-09-09 19:45 ` [tip:perf/core] perf, trace: Fix module leak tip-bot for Li Zefan
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