From: Masami Hiramatsu <mhiramat@redhat.com>
To: rostedt@goodmis.org
Cc: Frederic Weisbecker <fweisbec@gmail.com>,
Ingo Molnar <mingo@elte.hu>,
lkml <linux-kernel@vger.kernel.org>,
systemtap <systemtap@sources.redhat.com>,
DLE <dle-develop@lists.sourceforge.net>,
Jim Keniston <jkenisto@us.ibm.com>,
Ananth N Mavinakayanahalli <ananth@in.ibm.com>,
Andi Kleen <ak@linux.intel.com>,
Christoph Hellwig <hch@infradead.org>,
"Frank Ch. Eigler" <fche@redhat.com>,
"H. Peter Anvin" <hpa@zytor.com>,
Jason Baron <jbaron@redhat.com>,
"K.Prasad" <prasad@linux.vnet.ibm.com>,
Lai Jiangshan <laijs@cn.fujitsu.com>,
Li Zefan <lizf@cn.fujitsu.com>,
Peter Zijlstra <peterz@infradead.org>,
Srikar Dronamraju <srikar@linux.vnet.ibm.com>,
Tom Zanussi <tzanussi@gmail.com>
Subject: Re: [PATCH tracing/kprobes 5/7] tracing/kprobes: Add argument name support
Date: Fri, 11 Sep 2009 16:28:00 -0000 [thread overview]
Message-ID: <4AAA7B90.8010002@redhat.com> (raw)
In-Reply-To: <4AAA76B1.3020208@redhat.com>
Masami Hiramatsu wrote:
> Steven Rostedt wrote:
>> On Thu, 2009-09-10 at 19:53 -0400, Masami Hiramatsu wrote:
>>
>>> @@ -870,9 +892,13 @@ print_kprobe_event(struct trace_iterator *iter, int flags)
>>> {
>>> struct kprobe_trace_entry *field;
>>> struct trace_seq *s =&iter->seq;
>>> + struct trace_event *event;
>>> + struct trace_probe *tp;
>>> int i;
>>>
>>> field = (struct kprobe_trace_entry *)iter->ent;
>>> + event = ftrace_find_event(field->ent.type);
>>> + tp = container_of(event, struct trace_probe, event);
>>
>> Can this function be called the data is in the ring buffer, but the
>> probe has been unregistered? If so, the result of ftrace_find_event be
>> NULL?
>
> Hmm, it will depend on ftrace implementation. Before releasing
> trace_probe, kprobe tracer tries to unregister event call.
> If it's correctly locking mutex or some rw_lock for both of
> unregistering and printing, it will be safe.
>
> Unfortunately, it seems not :-(.
>
> In trace_events.c,
> 1054 static void __trace_remove_event_call(struct ftrace_event_call *call)
> 1055 {
> 1056 ftrace_event_enable_disable(call, 0);
> 1057 if (call->event)
> 1058 __unregister_ftrace_event(call->event);
>
> What we need to do is calling unregister_ftrace_event() instead of
> __unregister_ftrace_event.
Aah, NO. the caller of trace_remove_event_call() should have
trace_event_mutex before calling!
--
Masami Hiramatsu
Software Engineer
Hitachi Computer Products (America), Inc.
Software Solutions Division
e-mail: mhiramat@redhat.com
next prev parent reply other threads:[~2009-09-11 16:28 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-09-10 23:51 [PATCH tracing/kprobes 0/7] tracing/kprobes: kprobe-based event tracer update and perf support Masami Hiramatsu
2009-09-10 23:51 ` [PATCH tracing/kprobes 2/7] tracing/kprobes: Fix probe offset to be unsigned Masami Hiramatsu
2009-09-10 23:51 ` [PATCH tracing/kprobes 5/7] tracing/kprobes: Add argument name support Masami Hiramatsu
2009-09-11 14:08 ` Steven Rostedt
2009-09-11 16:07 ` Masami Hiramatsu
2009-09-11 16:28 ` Masami Hiramatsu [this message]
2009-09-10 23:51 ` [PATCH tracing/kprobes 1/7] x86/ptrace: Fix regs_get_argument_nth() to add correct offset Masami Hiramatsu
2009-09-11 1:43 ` Steven Rostedt
2009-09-10 23:51 ` [PATCH tracing/kprobes 4/7] tracing/kprobes: Add event profiling support Masami Hiramatsu
2009-09-11 3:13 ` Frederic Weisbecker
2009-09-11 16:18 ` Masami Hiramatsu
2009-09-14 3:02 ` Frederic Weisbecker
[not found] ` <4AAE7540.9090009@redhat.com>
2009-09-14 18:55 ` Frederic Weisbecker
[not found] ` <4AAE9B41.3020905@redhat.com>
2009-09-14 21:07 ` Frederic Weisbecker
2009-09-15 4:52 ` Ananth N Mavinakayanahalli
2009-09-11 19:26 ` Masami Hiramatsu
2009-09-14 3:08 ` Frederic Weisbecker
2009-09-13 10:07 ` [BUGFIX] kprobes: prevent re-registration of the same kprobe Ananth N Mavinakayanahalli
[not found] ` <4AADA0BB.4030307@redhat.com>
2009-09-14 10:05 ` [BUGFIX] kprobes: prevent re-registration of the same kprobe - take2 Ananth N Mavinakayanahalli
[not found] ` <4AAE6E85.9020002@redhat.com>
2009-09-15 5:19 ` Ananth N Mavinakayanahalli
2009-09-16 23:52 ` Masami Hiramatsu
2009-09-10 23:51 ` [PATCH tracing/kprobes 3/7] tracing/kprobes: Cleanup kprobe tracer code Masami Hiramatsu
2009-09-11 2:33 ` Daniel Walker
2009-09-11 2:36 ` Frederic Weisbecker
2009-09-10 23:52 ` [PATCH tracing/kprobes 6/7] tracing/kprobes: Show event name in trace output Masami Hiramatsu
2009-09-10 23:52 ` [PATCH tracing/kprobes 7/7] tracing/kprobes: Support custom subsystem for each kprobe event Masami Hiramatsu
2009-09-11 1:33 ` [PATCH tracing/kprobes 0/7] tracing/kprobes: kprobe-based event tracer update and perf support Frederic Weisbecker
2009-09-11 1:45 ` Steven Rostedt
2009-09-11 15:59 ` Masami Hiramatsu
2009-09-14 3:00 ` Frederic Weisbecker
[not found] ` <4AAE7A5D.8010503@redhat.com>
2009-09-14 20:53 ` Frederic Weisbecker
[not found] ` <4AAEB149.2070300@redhat.com>
2009-09-14 21:09 ` Frederic Weisbecker
2009-09-11 19:03 ` Frank Ch. Eigler
2009-09-11 19:07 ` Christoph Hellwig
2009-09-11 19:51 ` Mark Wielaard
[not found] ` <20090911200317.GA3827@infradead.org>
2009-09-12 1:20 ` Masami Hiramatsu
2009-09-11 19:15 ` Frederic Weisbecker
2009-09-11 15:36 ` Frederic Weisbecker
2009-09-11 21:44 ` Masami Hiramatsu
2009-09-14 2:23 ` Frederic Weisbecker
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