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From: Oleg Nesterov <oleg@redhat.com>
To: Namhyung Kim <namhyung@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>,
	Namhyung Kim <namhyung.kim@lge.com>,
	Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>,
	Hyeoncheol Lee <cheol.lee@lge.com>,
	Hemant Kumar <hkshaw@linux.vnet.ibm.com>,
	LKML <linux-kernel@vger.kernel.org>,
	Srikar Dronamraju <srikar@linux.vnet.ibm.com>,
	"zhangwei(Jovi)" <jovi.zhangwei@huawei.com>,
	Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Subject: Re: [PATCH 10/13] tracing/uprobes: Fetch args before reserving a ring buffer
Date: Mon, 4 Nov 2013 15:35:17 +0100	[thread overview]
Message-ID: <20131104143517.GA4440@redhat.com> (raw)
In-Reply-To: <87y554382a.fsf@sejong.aot.lge.com>

Hi Namhyung,

On 11/04, Namhyung Kim wrote:
>
> >>
> >> +	if (atomic_dec_and_test(&uprobe_buffer_ref)) {
> >> +		free_percpu(uprobe_cpu_buffer);
> >> +		uprobe_cpu_buffer = NULL;
> >> +	}
> >> +
> >>  	WARN_ON(!uprobe_filter_is_empty(&tu->filter));
> >
> > Do we really need atomic_t? probe_event_enable/disable is called under
> > event_mutex and we rely on this fact anyway.
>
> Looking at the code, it seems probe_event_enable/disable() is called
> without event_mutex when it called from sys_perf_event_open().

Where?

__ftrace_set_clr_event(), perf_trace_init() or perf_trace_destroy()
hold event_mutex. We rely on this fact anyway.

Oleg.


  reply	other threads:[~2013-11-04 14:34 UTC|newest]

Thread overview: 92+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-10-29  6:53 [PATCHSET 00/13] tracing/uprobes: Add support for more fetch methods (v6) Namhyung Kim
2013-10-29  6:53 ` [PATCH 01/13] tracing/uprobes: Fix documentation of uprobe registration syntax Namhyung Kim
2013-10-29  6:53 ` [PATCH 02/13] tracing/probes: Fix basic print type functions Namhyung Kim
2013-10-29  6:53 ` [PATCH 03/13] tracing/kprobes: Move fetch functions to trace_kprobe.c Namhyung Kim
2013-10-29  6:53 ` [PATCH 04/13] tracing/kprobes: Add fetch{,_size} member into deref fetch method Namhyung Kim
2013-10-29  6:53 ` [PATCH 05/13] tracing/kprobes: Staticize stack and memory fetch functions Namhyung Kim
2013-10-29  6:53 ` [PATCH 06/13] tracing/kprobes: Factor out struct trace_probe Namhyung Kim
2013-10-29  6:53 ` [PATCH 07/13] tracing/uprobes: Convert to " Namhyung Kim
2013-10-29  6:53 ` [PATCH 08/13] tracing/kprobes: Move common functions to trace_probe.h Namhyung Kim
2013-10-29  6:53 ` [PATCH 09/13] tracing/kprobes: Integrate duplicate set_print_fmt() Namhyung Kim
2013-10-29  6:53 ` [PATCH 10/13] tracing/uprobes: Fetch args before reserving a ring buffer Namhyung Kim
2013-10-31 18:16   ` Oleg Nesterov
2013-11-01  9:00     ` Namhyung Kim
2013-11-04  8:06     ` Namhyung Kim
2013-11-04 14:35       ` Oleg Nesterov [this message]
2013-11-05  1:12         ` Namhyung Kim
2013-11-01 15:09   ` Oleg Nesterov
2013-11-01 15:22     ` Oleg Nesterov
2013-11-03 20:20       ` Oleg Nesterov
2013-11-04  8:11         ` Namhyung Kim
2013-11-04 14:38           ` Oleg Nesterov
2013-11-05  1:17             ` Namhyung Kim
2013-10-29  6:53 ` [PATCH 11/13] tracing/kprobes: Add priv argument to fetch functions Namhyung Kim
2013-11-04 16:09   ` Oleg Nesterov
2013-11-05  2:10     ` Namhyung Kim
2013-10-29  6:53 ` [PATCH 12/13] tracing/uprobes: Add more " Namhyung Kim
2013-10-31 18:22   ` Oleg Nesterov
2013-11-04  8:50     ` Namhyung Kim
2013-11-04 16:44       ` Oleg Nesterov
2013-11-04 17:17         ` Steven Rostedt
2013-11-05  2:19           ` Namhyung Kim
2013-11-05  2:17         ` Namhyung Kim
2013-11-01 17:53   ` Oleg Nesterov
2013-10-29  6:53 ` [PATCH 13/13] tracing/uprobes: Add support for full argument access methods Namhyung Kim
2013-10-30 10:36 ` [PATCHSET 00/13] tracing/uprobes: Add support for more fetch methods (v6) Masami Hiramatsu
2013-11-02 15:54 ` Oleg Nesterov
2013-11-04  8:46   ` Namhyung Kim
2013-11-04  8:59     ` Namhyung Kim
2013-11-04 15:51       ` Oleg Nesterov
2013-11-04 16:22         ` Oleg Nesterov
2013-11-04 18:47           ` Oleg Nesterov
2013-11-04 18:57             ` Oleg Nesterov
2013-11-05  2:51               ` Namhyung Kim
2013-11-05 16:41                 ` Oleg Nesterov
2013-11-06  8:37                   ` Namhyung Kim
2013-11-05  2:49             ` Namhyung Kim
2013-11-05  6:58             ` Namhyung Kim
2013-11-05 17:45               ` Oleg Nesterov
2013-11-05 19:24                 ` Oleg Nesterov
2013-11-06  8:57                   ` Namhyung Kim
2013-11-06 17:37                     ` Oleg Nesterov
2013-11-06 18:24                       ` Oleg Nesterov
2013-11-07  9:00                         ` Namhyung Kim
2013-11-08 17:00                           ` Oleg Nesterov
2013-11-12  7:49                             ` Namhyung Kim
2013-11-07  8:48                       ` Namhyung Kim
2013-11-09  3:18                         ` Masami Hiramatsu
2013-11-09 15:23                           ` Oleg Nesterov
2013-11-12  8:00                             ` Namhyung Kim
2013-11-12 18:44                               ` Oleg Nesterov
2013-11-25  6:59                               ` Namhyung Kim
2013-11-25 14:12                                 ` [PATCH] uprobes: Allocate ->utask before handler_chain() for tracing handlers Oleg Nesterov
2013-11-06  8:48                 ` [PATCHSET 00/13] tracing/uprobes: Add support for more fetch methods (v6) Namhyung Kim
2013-11-06 16:28                   ` Oleg Nesterov
2013-11-07  7:33                     ` Namhyung Kim
2013-11-08 16:52                       ` Oleg Nesterov
2013-11-05  2:15           ` Namhyung Kim
2013-11-05 16:33             ` Oleg Nesterov
2013-11-06  8:34               ` Namhyung Kim
2013-11-05  1:59         ` Namhyung Kim
2013-11-04 15:01     ` Oleg Nesterov
2013-11-05  1:53       ` Namhyung Kim
2013-11-05 16:28         ` Oleg Nesterov
2013-11-06  8:31           ` Namhyung Kim
  -- strict thread matches above, loose matches on Subject: below --
2013-09-03  5:44 [PATCHSET 00/13] tracing/uprobes: Add support for more fetch methods (v5) Namhyung Kim
2013-09-03  5:44 ` [PATCH 10/13] tracing/uprobes: Fetch args before reserving a ring buffer Namhyung Kim
2013-09-03 10:50   ` Masami Hiramatsu
2013-09-04  7:08     ` Namhyung Kim
2013-09-03 11:10   ` zhangwei(Jovi)
2013-09-04  7:10     ` Namhyung Kim
2013-08-27  8:48 [PATCHSET 00/13] tracing/uprobes: Add support for more fetch methods (v4) Namhyung Kim
2013-08-27  8:48 ` [PATCH 10/13] tracing/uprobes: Fetch args before reserving a ring buffer Namhyung Kim
2013-08-09  8:44 [PATCHSET 00/13] tracing/uprobes: Add support for more fetch methods (v3) Namhyung Kim
2013-08-09  8:45 ` [PATCH 10/13] tracing/uprobes: Fetch args before reserving a ring buffer Namhyung Kim
2013-08-09  9:56   ` Masami Hiramatsu
2013-08-09 16:20     ` Oleg Nesterov
2013-08-09 16:21       ` Oleg Nesterov
2013-08-10  1:26       ` zhangwei(Jovi)
2013-08-10  1:41         ` zhangwei(Jovi)
2013-08-10 14:06           ` zhangwei(Jovi)
2013-08-22 16:42     ` Steven Rostedt
2013-08-22 23:57       ` zhangwei(Jovi)
2013-08-23  1:08         ` Steven Rostedt
2013-08-27  8:07           ` Namhyung Kim
2013-08-23  4:22         ` Masami Hiramatsu

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