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From: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>,
	Ingo Molnar <mingo@elte.hu>,
	linux-kernel@vger.kernel.org, yrl.pp-manager.tt@hitachi.com,
	Frederic Weisbecker <fweisbec@gmail.com>,
	Ingo Molnar <mingo@redhat.com>,
	"Frank Ch. Eigler" <fche@redhat.com>
Subject: Re: [PATCH 1/4] [BUGFIX] ftrace/kprobes: Fix not to delete probes if in use
Date: Mon, 10 Oct 2011 23:14:59 +0900
Message-ID: <4E92FDE3.8050301@hitachi.com> (raw)
In-Reply-To: <1318050006.4729.103.camel@gandalf.stny.rr.com>

(2011/10/08 14:00), Steven Rostedt wrote:
> On Tue, 2011-10-04 at 19:44 +0900, Masami Hiramatsu wrote:
>> Fix kprobe-tracer not to delete a probe if the probe is in use.
>> In that case, delete operation will return -EBUSY.
>>
>> This bug can cause a kernel panic if enabled probes are deleted
>> during perf record.
>>
>> (Add some probes on functions)
>> # perf record -e probe:\* -aR sh
>> sh-4.2# perf probe --del probe:\*
>> sh-4.2# exit
>> (kernel panic)
> 
> 
> Hi Masami,
> 
> I was able to reproduce the panic. I'm currently running patch 1 and 4
> through my standard tests before pushing this out as urgent.
> 
> Does this exist in previous kernels? If so, I'll also add the stable tag
> to it.

I guess so, since the perf's tracepoint handler locks target module
while recording, it is required for perf not to remove undergo events.

> Could you resend the trivial patches when you make your necessary
> corrections. They are not important as these are and I'll add them to a
> separate queue.

Right, that's not a matter. The first patch should be merged soon.

Thank you,

> 
> Thanks!
> 
> -- Steve
> 
> 
> --
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-- 
Masami HIRAMATSU
Software Platform Research Dept. Linux Technology Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu.pt@hitachi.com

  reply index

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-10-04 10:44 Masami Hiramatsu
2011-10-04 10:44 ` [PATCH 2/4] [TRIVIAL] ftrace/kprobes: Fix an warning typo Masami Hiramatsu
2011-10-04 15:58   ` Valdis.Kletnieks
2011-10-05  4:08     ` Masami Hiramatsu
2011-10-04 10:44 ` [PATCH 3/4] [TRIVIAL] perftools: Fix a typo of command name as trace-cmd Masami Hiramatsu
2011-10-04 10:45 ` [PATCH 4/4] [BUGFIX] perf probe: Fix to show correct error string Masami Hiramatsu
2011-10-08  5:00 ` [PATCH 1/4] [BUGFIX] ftrace/kprobes: Fix not to delete probes if in use Steven Rostedt
2011-10-10 14:14   ` Masami Hiramatsu [this message]
2011-10-10 19:11     ` Steven Rostedt

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