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From: Masami Hiramatsu <mhiramat@kernel.org>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: linux-kernel@vger.kernel.org, Ingo Molnar <mingo@kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Tom Zanussi <tom.zanussi@linux.intel.com>,
	Clark Williams <williams@redhat.com>,
	Karim Yaghmour <karim.yaghmour@opersys.com>,
	Brendan Gregg <bgregg@netflix.com>,
	Joel Fernandes <joelaf@google.com>,
	Masami Hiramatsu <mhiramat@kernel.org>,
	Namhyung Kim <namhyung@kernel.org>,
	linux-rt-users@vger.kernel.org
Subject: Re: [RFC][PATCH 07/10] tracing: Have zero size length in filter logic be full string
Date: Sat, 12 May 2018 21:40:29 +0900	[thread overview]
Message-ID: <20180512214029.8610c88ecc3de94a95822189@kernel.org> (raw)
In-Reply-To: <20180511195341.034688188@goodmis.org>

On Fri, 11 May 2018 15:49:34 -0400
Steven Rostedt <rostedt@goodmis.org> wrote:

> From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>
> 
> As strings in trace events may not have a nul terminating character, the
> filter string compares use the defined string length for the field for the
> compares.
> 
> The trace_marker records data slightly different than do normal events. It's
> size is zero, meaning that the string is the rest of the array, and that the
> string also ends with '\0'.
> 
> If the size is zero, assume that the string is nul terminated and read the
> string in question as is.
> 
> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
> ---
>  kernel/trace/trace_events_filter.c | 23 ++++++++++++-----------
>  1 file changed, 12 insertions(+), 11 deletions(-)
> 
> diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c
> index 7d306b74230f..675392b9edd2 100644
> --- a/kernel/trace/trace_events_filter.c
> +++ b/kernel/trace/trace_events_filter.c
> @@ -750,31 +750,32 @@ static int filter_pred_none(struct filter_pred *pred, void *event)
>   *
>   * Note:
>   * - @str might not be NULL-terminated if it's of type DYN_STRING
> - *   or STATIC_STRING
> + *   or STATIC_STRING, unless @len is zero.
>   */
>  
>  static int regex_match_full(char *str, struct regex *r, int len)
>  {
> -	if (strncmp(str, r->pattern, len) == 0)
> -		return 1;
> -	return 0;
> +	/* len means str is dynamic and ends with '\0' */
           ^^^
          !len (or len == 0)?

Thank you,




-- 
Masami Hiramatsu <mhiramat@kernel.org>

  reply	other threads:[~2018-05-12 12:40 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-05-11 19:49 [RFC][PATCH 00/10] tracing: Add triggers to trace_marker writes Steven Rostedt
2018-05-11 19:49 ` [RFC][PATCH 01/10] tracing: Do not reference event data in post call triggers Steven Rostedt
2018-05-12 12:04   ` Masami Hiramatsu
2018-05-11 19:49 ` [RFC][PATCH 02/10] tracing: Add __find_event_file() to find event files without restrictions Steven Rostedt
2018-05-11 19:49 ` [RFC][PATCH 03/10] tracing: Have event_trace_init() called by trace_init_tracefs() Steven Rostedt
2018-05-11 19:49 ` [RFC][PATCH 04/10] tracing: Add brackets in ftrace event dynamic arrays Steven Rostedt
2018-05-11 19:49 ` [RFC][PATCH 05/10] tracing: Do not show filter file for ftrace internal events Steven Rostedt
2018-05-11 19:49 ` [RFC][PATCH 06/10] tracing: Add trigger file for trace_markers tracefs/ftrace/print Steven Rostedt
2018-05-14  3:13   ` Namhyung Kim
2018-05-14 15:04     ` Steven Rostedt
2018-05-16  7:49       ` Namhyung Kim
2018-05-16 10:37         ` Steven Rostedt
2018-05-11 19:49 ` [RFC][PATCH 07/10] tracing: Have zero size length in filter logic be full string Steven Rostedt
2018-05-12 12:40   ` Masami Hiramatsu [this message]
2018-05-12 17:27     ` Steven Rostedt
2018-05-12 18:32   ` Yann Ylavic
2018-05-14  2:23     ` Namhyung Kim
2018-05-14 14:12     ` Steven Rostedt
2018-05-11 19:49 ` [RFC][PATCH 08/10] tracing: Prevent further users of zero size static arrays in trace events Steven Rostedt
2018-05-11 19:49 ` [RFC][PATCH 09/10] tracing: Allow histogram triggers to access ftrace internal events Steven Rostedt
2018-05-11 19:49 ` [RFC][PATCH 10/10] tracing: Document trace_marker triggers Steven Rostedt

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