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From: Steven Rostedt <rostedt@goodmis.org>
To: Masami Hiramatsu <mhiramat@kernel.org>
Cc: linux-kernel@vger.kernel.org, Ingo Molnar <mingo@kernel.org>,
	Tom Zanussi <tom.zanussi@linux.intel.com>,
	Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
Subject: Re: [PATCH v2 01/12] tracing/uprobes: Add busy check when cleanup all uprobes
Date: Tue, 4 Dec 2018 12:43:33 -0500
Message-ID: <20181204124333.00f4c5ee@vmware.local.home> (raw)
In-Reply-To: <154140841557.17322.12653952888762532401.stgit@devbox>

On Mon,  5 Nov 2018 18:00:15 +0900
Masami Hiramatsu <mhiramat@kernel.org> wrote:

> Add a busy check loop in cleanup_all_probes() before
> trying to remove all events in uprobe_events as same as
> kprobe_events does.
> 
> Without this change, writing null to uprobe_events will
> try to remove events but if one of them is enabled, it
> stopped there but some of events are already cleared.
> 
> With this change, writing null to uprobe_events make
> sure all events are not enabled before removing events.
> So, it clears all events, or return an error (-EBUSY)
> with keeping all events.
> 

Hmm, should this patch be marked as stable?

-- Steve

> Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
> ---
>  kernel/trace/trace_uprobe.c |    7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
> index 31ea48eceda1..b708e4ff7ea7 100644
> --- a/kernel/trace/trace_uprobe.c
> +++ b/kernel/trace/trace_uprobe.c
> @@ -587,12 +587,19 @@ static int cleanup_all_probes(void)
>  	int ret = 0;
>  
>  	mutex_lock(&uprobe_lock);
> +	/* Ensure no probe is in use. */
> +	list_for_each_entry(tu, &uprobe_list, list)
> +		if (trace_probe_is_enabled(&tu->tp)) {
> +			ret = -EBUSY;
> +			goto end;
> +		}
>  	while (!list_empty(&uprobe_list)) {
>  		tu = list_entry(uprobe_list.next, struct trace_uprobe, list);
>  		ret = unregister_trace_uprobe(tu);
>  		if (ret)
>  			break;
>  	}
> +end:
>  	mutex_unlock(&uprobe_lock);
>  	return ret;
>  }


  reply index

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-11-05  8:59 [PATCH v2 00/12] tracing: Unifying dynamic event interface Masami Hiramatsu
2018-11-05  9:00 ` [PATCH v2 01/12] tracing/uprobes: Add busy check when cleanup all uprobes Masami Hiramatsu
2018-12-04 17:43   ` Steven Rostedt [this message]
2018-12-07  2:19     ` Masami Hiramatsu
2018-11-05  9:00 ` [PATCH v2 02/12] tracing: Lock event_mutex before synth_event_mutex Masami Hiramatsu
2018-11-05  9:01 ` [PATCH v2 03/12] tracing: Simplify creation and deletion of synthetic event Masami Hiramatsu
2018-11-05  9:01 ` [PATCH v2 04/12] tracing: Integrate similar probe argument parsers Masami Hiramatsu
2018-11-05  9:02 ` [PATCH v2 05/12] tracing: Add unified dynamic event framework Masami Hiramatsu
2018-11-05  9:02 ` [PATCH v2 06/12] tracing/kprobes: Use dyn_event framework for kprobe events Masami Hiramatsu
2018-11-05  9:03 ` [PATCH v2 07/12] tracing/uprobes: Use dyn_event framework for uprobe events Masami Hiramatsu
2018-11-05  9:03 ` [PATCH v2 08/12] tracing: Use dyn_event framework for synthetic events Masami Hiramatsu
2018-11-05  9:04 ` [PATCH v2 09/12] tracing: Remove unneeded synth_event_mutex Masami Hiramatsu
2018-11-05  9:04 ` [PATCH v2 10/12] tracing: Remove orphaned trace_add/remove_event_call functions Masami Hiramatsu
2018-12-04 18:51   ` Steven Rostedt
2018-12-07  2:22     ` Masami Hiramatsu
2018-11-05  9:04 ` [PATCH v2 11/12] tracing: Add generic event-name based remove event method Masami Hiramatsu
2018-11-05  9:05 ` [PATCH v2 12/12] selftests/ftrace: Add testcases for dynamic event Masami Hiramatsu
2018-11-28  7:31 ` [PATCH v2 00/12] tracing: Unifying dynamic event interface Masami Hiramatsu
2018-11-28 23:42   ` Tom Zanussi
2018-11-29  3:46     ` Steven Rostedt
2018-11-29  5:20     ` Masami Hiramatsu
2018-11-29 15:08       ` Tom Zanussi

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